Estimation of the largest expected photovoltaic power ramp rates

Photovoltaic (PV) systems are prone to irradiance variation caused by cloud shadows leading to fluctuations in generated power. Since these fluctuations can be harmful to the operation of power grids, there is a need to restrict the largest PV power ramp rates (RR). This article proposes a method to estimate the largest expected PV power RRs. The only inputs of the method are the minimum PV system dimension and the measurements of point irradiance and cloud shadow velocity. Since cloud shadows cause the largest power RRs for well-designed large-scale PV power plants, the relation between the largest RRs in irradiance and power during partial cloud shading events was studied based on irradiance measurements. The largest RRs in PV power are estimated from RRs in the average irradiance across the PV system. The proposed method was validated using measured data of 57 days from two PV systems. It showed superior performance compared to an existing method enveloping the RR in the measured power over 99.99% of the time. The method can be used in design and component sizing of PV power plants.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Engineering, Research group: Power systems, Research area: Power engineering, University of California
Contributors: Lappalainen, K., Wang, G. C., Kleissl, J.
Number of pages: 13
Publication date: 15 Nov 2020
Peer-reviewed: Yes

Publication information

Journal: Applied Energy
Volume: 278
Article number: 115636
ISSN (Print): 0306-2619
Original language: English
ASJC Scopus subject areas: Building and Construction, Energy(all), Mechanical Engineering, Management, Monitoring, Policy and Law
Keywords: Energy storage sizing, Irradiance transition, Partial shading, Photovoltaic power generation, Power fluctuation, Power ramp rate estimation
Electronic versions: 
Source: Scopus
Source ID: 85088961600

Research output: Contribution to journalArticleScientificpeer-review

Tuning electricity generation throughout the year with PV module technology

Currently, photovoltaic (PV) installations target a maximization of annual energy yield. However, as the grid penetration of PV is increasing, PV electricity generation will need to match better with local load profiles. Especially the seasonal variabilities remain challenging. While wind and PV tend to have complementary seasonal variability, wind turbine installation faces limitations especially in densely populated areas. In this paper, we discuss how this challenge may be addressed with climate- and consumption-specific PV module technology. In particular, we demonstrate how the temperature coefficient of a PV system can impact the energy yield throughout the year. In colder climates, higher temperature coefficients allow for a better energy balance, favoring production in colder seasons without a significant reduction of yearly energy yield. Simulations for locations at high latitude, and colder climates, indicate that higher temperature coefficients and improved low-light behavior not only enable a higher energy yield in cold seasons, but also negligible losses in the overall yearly energy yield compared to lower temperature coefficients and slightly better low-light behavior. Simulations show that these results can be obtained using commercial PV modules. More broadly, they indicate how PV module technology may be optimized depending on the location and climate.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Engineering, Research group: Power systems, Research area: Power engineering, Imec, EnergyVille, KU Leuven, College of Engineering and Petroleum Kuwait, 3Carleton University, Hasselt University
Contributors: Manganiello, P., Govaerts, J., Horvath, I. T., Chowdhury, M. G., Yordanov, G. H., Goverde, H., Aldalali, B., Beausoleil-Morrison, I., Valkealahti, S., Lappalainen, K., Poortmans, J.
Number of pages: 10
Pages: 418-427
Publication date: 1 Nov 2020
Peer-reviewed: Yes

Publication information

Journal: Renewable Energy
Volume: 160
ISSN (Print): 0960-1481
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment
Keywords: Energy yield simulation, Low-light performance, PV module Technology, Seasonal balancing by tuning PV generation, Temperature coefficient
Source: Scopus
Source ID: 85088041728

Research output: Contribution to journalArticleScientificpeer-review

How consumers’ respect for nature and environmental self-assets influence their car brand experiences

This paper provides a novel perspective on sustainability research by exploring how two pro-environmental characteristics of consumers – respect for nature and environmental self-assets – influence their brand experiences. The study uses survey data collected on a car brand that incorporated eco-friendly advances. The results show that respect for nature has an impact on how respondents experience the eco-friendliness of brands and that eco-friendly brand experiences in turn influence general brand experiences. The findings also suggest that the effects of the two pro-environmental characteristics depend on the education level of the consumer: eco-friendly brand experiences of highly educated consumers are affected by their respect for nature, whereas those of consumers with lower education levels are affected by environmental self-assets.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Industrial Engineering and Management, Research group: Center for Innovation and Technology Research, Jönköping International Business School, University of Graz, Radboud University Nijmegen, Nyenrode Business Universiteit
Contributors: Saari, U. A., Mäkinen, S. J., Baumgartner, R. J., Hillebrand, B., Driessen, P. H.
Publication date: 10 Jul 2020
Peer-reviewed: Yes

Publication information

Journal: Journal of Cleaner Production
Volume: 261
Article number: 121023
ISSN (Print): 0959-6526
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Environmental Science(all), Strategy and Management, Industrial and Manufacturing Engineering
Keywords: Automotive industry, Brand experience, Car brand, Eco-friendliness, Partial least squares structural equation modeling, Pro-environmental characteristics
Source: Scopus
Source ID: 85082527690

Research output: Contribution to journalArticleScientificpeer-review

Comprehensive assessment brings out shortcomings in almost every school building

Consideration of the big picture is needed when evaluating aspects of the building with relevance for reporting of poor indoor air quality or symptoms. Even the most accurate longitudinal measurements do not remove the need for expertise and broad understanding of the different possible sources and causes of indoor air exposures. Finnish Institute for Health and Welfare (THL), in collaboration with Tampere University (TAU), studies the association between school buildings of Helsinki and pupil reported health symptoms. The present paper focuses on introducing the methods and classifications as well as presenting the results about the condition of the buildings. Characteristics of 53 school buildings have been assessed by visiting the buildings and by going through the previous building investigation reports. Visits relied mainly on visual inspections with an extensive checklist and some none intrusive momentary measurements about the dampness, pressure difference, and indoor air quality (IAQ). The major strength of the study is that all the possible school buildings in certain areas were inspected and assessed using the same methods, irrespective if the building had a long history of indoor air problems or not. That makes it possible to evaluate the general prevalence of the problems in school buildings, which has been highlighted as an open question by the National Indoor Air and Health Program 2018-2028, coordinated by THL. The first results indicate that every school building has its shortcomings. However, none of the studied buildings was in a very bad condition either. The results indicate that it is not possible to draw a clear line between the buildings with 'good' or 'poor' IAQ.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Research group: Service Life Engineering of Structures, Finnish Institute for Health and Welfare
Contributors: Marttila, T., Lahdensivu, J., Pekkanen, J.
Number of pages: 8
Publication date: 30 Jun 2020
Peer-reviewed: Yes

Publication information

Journal: E3S Web of Conferences
Volume: 172
Article number: 23002
ISSN (Print): 2555-0403
Original language: English
ASJC Scopus subject areas: Environmental Science(all), Energy(all), Earth and Planetary Sciences(all)
Electronic versions: 
Source: Scopus
Source ID: 85088449337

Research output: Contribution to journalConference articleScientificpeer-review

Laboratory tests and modelling of mineral wool insulated steel sandwich panels

This study presents results from laboratory measurements of mineral wool insulated steel sandwich panels. The purpose of the work was to have a better understanding on the heat and moisture conditions inside sandwich panels and to study how the structure behaves in water leakage situation. The tests were done by sealing the structure from all sides and regulating the temperature on one side of the test structure while measuring the temperature and relative humidity conditions inside the structure. Water leakages were created by injecting liquid water onto the insulation layer. According to the results, water vapour pressure differences stayed relatively small both in stationary and dynamic conditions. This implies that the limiting factor for moisture source was the evaporation rate from the water leakage and that the vapour pressure throughout the insulation layer is determined strongly by the vapour pressure at the possible condensation layer. The paper discusses also the determination of sensor accuracy and impacts of a thermal bridge from the probe itself. Also, measurement results from a new radio wave monitoring method are presented.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Research group: Building Physics, Tallinn University of Technology, SSAB, Smart City Center of Excellence (Finest Twins)
Contributors: Laukkarinen, A., Vinha, J., Kalbe, K., Kesti, J., Kalamees, T., Honkakoski, E.
Number of pages: 8
Publication date: 30 Jun 2020
Peer-reviewed: Yes

Publication information

Journal: E3S Web of Conferences
Volume: 172
Article number: 17006
ISSN (Print): 2555-0403
Original language: English
ASJC Scopus subject areas: Energy(all), Building and Construction
Keywords: Building physics, moisture behavior, Sandwich panels, laboratory testing
Electronic versions: 

Bibliographical note

EXT="Kalamees, Targo"

Source: Scopus
Source ID: 85088420453

Research output: Contribution to journalConference articleScientificpeer-review

Ministry of the Environment announces a Guide on Renovation and Repair of Buildings with Moisture and Microbial Damage - From theory to practice

In 2015, the Ministry of the Environment in Finland renewed the legislation and the National Building Code of Finland. It released completely new legislation concerning repair design. This was due to widely known issues relating to the indoor air quality of private and public buildings. In the autumn of 2019, the Ministry of the Environment in Finland published a guide concerning the repairs of moisture and microbial damage. It is available in Finnish and Swedish. This guide is a follow-up of the Environmental Guide "Building Moisture and Indoor Air Quality Assessment", published 2016. It completes the series of guides for the execution of a project repairing indoor air quality issues, from a condition assessment to the completion of repairs and the implementation of the building. These guides lead through common practices and how these issues shall be dealt with in Finland.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Research group: Service Life Engineering of Structures, Ramboll Finland Ltd., Aalto University
Contributors: Weijo, I., Turunen, T., Lahdensivu, J., Sistonen, E., Annila, P.
Number of pages: 6
Publication date: 30 Jun 2020
Peer-reviewed: Yes

Publication information

Journal: E3S Web of Conferences
Volume: 172
Article number: 20007
ISSN (Print): 2555-0403
Original language: English
ASJC Scopus subject areas: Environmental Science(all), Energy(all), Earth and Planetary Sciences(all)
Electronic versions: 

Bibliographical note

EXT="Weijo, Inari"

Source: Scopus
Source ID: 85088468858

Research output: Contribution to journalConference articleScientificpeer-review

Reliability of the detection of moisture and mould damage in visual inspections

Moisture and mould damage are common in Finnish public buildings. Due to the possible health hazards of such damage, more efficient detection methods and protocols are needed to examine it. The aim of this study is to examine the reliability of visual inspection in the detection of moisture and mould damage. The study points out that the reliability of all the research material is 70%. The highest reliability values concentrate on those structures where the repair need is highest. However, the range of reliability values is wide: from 0% to 100% depending on the age of building or structure. Reliability is highest in the most simplified structures and lowest in structures consisting of multiple layers of different building materials.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Research group: Service Life Engineering of Structures
Contributors: Annila, P. J., Lahdensivu, J.
Number of pages: 7
Publication date: 30 Jun 2020
Peer-reviewed: Yes

Publication information

Journal: E3S Web of Conferences
Volume: 172
Article number: 23004
ISSN (Print): 2555-0403
Original language: English
ASJC Scopus subject areas: Environmental Science(all), Energy(all), Earth and Planetary Sciences(all)
Electronic versions: 
Source: Scopus
Source ID: 85088446724

Research output: Contribution to journalConference articleScientificpeer-review

Current collectors for low resistance aqueous flexible printed supercapacitors

In this paper we propose various current collector alternatives to be used in flexible supercapacitors with aqueous electrolyte when low equivalent series resistance (ESR) is required. The current collector material should be corrosion resistant when in contact with the saline electrolyte. Simultaneously it should have high electrical conductivity. In addition, environmental and cost aspects must be taken into account. We report supercapacitors with current collectors made of two different thicknesses of graphite foil (25 µm and 150 µm) and aluminium coated with graphite inks. These disposable and non-toxic supercapacitors show remarkable improvements in ESR compared with values obtained for similar components with current collectors made of graphite ink. When graphite foil or aluminium is used as current collector, the ESR can be decreased by more than 80 % compared to using graphite ink alone. Supercapacitors using a dense graphite protective layer on top of aluminium showed no sign of corrosion and their performance was not significantly reduced after ageing for 950 days. With graphite foils, comparable ESR values can be obtained as with aluminium. The graphite foil is an interesting alternative if metal materials should be avoided, e.g. to facilitate incineration of the supercapacitors together with regular household waste. Especially with non-porous graphite foil, we obtained properties suitable for practical applications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Engineering, Research group: Laboratory for Future Electronics, Materials Science and Environmental Engineering, Abo Akad Univ, Abo Akademi University, Dept Phys, Microscopy Center
Contributors: Arvani, M., Keskinen, J., Lupo, D., Honkanen, M.
Number of pages: 5
Publication date: 1 Jun 2020
Peer-reviewed: Yes

Publication information

Journal: Journal of Energy Storage
Volume: 29
Article number: 101384
ISSN (Print): 2352-152X
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Electrical and Electronic Engineering
Keywords: Aluminium, Current collector, Energy storage, Graphite, Printed electronics, Supercapacitors
Electronic versions: 
Source: Scopus
Source ID: 85083673350

Research output: Contribution to journalArticleScientificpeer-review

Operation of a PV power plant during overpower events caused by the cloud enhancement phenomenon

Partly cloudy days possess two characteristics that can significantly increase the photovoltaic (PV) generator power: the operating temperature of the PV panels can cool down during the shade periods, and the irradiance can be enhanced due to the cloud enhancement phenomenon. If an overirradiance event is preceded by a long shade period, the maximum power of a PV generator can occasionally be much higher than the nominal nameplate power. During the overpower events, the inverter is operating in power-limiting mode whereby the operating voltage is increased to decrease the power of the PV generator. We created a simulation model of a 31.9 kW PV generator and used 12 months of irradiance and PV panel temperature measurement data to analyze its operation. We analyzed the PV generator power during the overirradiance events and applied various static power limits to calculate the operating voltage ranges in case of power curtailment. During the observation period, the maximum power produced by the PV generator was 1.42 times its nominal power. The duration of the overpower events was up to several minutes, but the typical duration was only some tens of seconds. The strongest overpower events occur seldom and their duration is only some seconds. Due to the overpower events, the operating voltage may receive high values, especially if the DC-to-AC power ratio is large.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Engineering, Research group: Power systems, Research area: Power engineering
Contributors: Järvelä, M., Valkealahti, S.
Number of pages: 15
Publication date: 1 May 2020
Peer-reviewed: Yes

Publication information

Journal: Energies
Volume: 13
Issue number: 9
Article number: 2185
ISSN (Print): 1996-1073
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Energy (miscellaneous), Control and Optimization, Electrical and Electronic Engineering
Keywords: Cloud enhancement, Operating voltage, Overirradiance, PV cell temperature, PV generator
Electronic versions: 
Source: Scopus
Source ID: 85084553260

Research output: Contribution to journalArticleScientificpeer-review

Assessing and comparing short term load forecasting performance

When identifying and comparing forecasting models, there may be a risk that poorly selected criteria could lead to wrong conclusions. Thus, it is important to know how sensitive the results are to the selection of criteria. This contribution aims to study the sensitivity of the identification and comparison results to the choice of criteria. It compares typically applied criteria for tuning and performance assessment of load forecasting methods with estimated costs caused by the forecasting errors. The focus is on short-term forecasting of the loads of energy systems. The estimated costs comprise electricity market costs and network costs. We estimate the electricity market costs by assuming that the forecasting errors cause balancing errors and consequently balancing costs to the market actors. The forecasting errors cause network costs by overloading network components thus increasing losses and reducing the component lifetime or alternatively increase operational margins to avoid those overloads. The lifetime loss of insulators, and thus also the components, is caused by heating according to the law of Arrhenius. We also study consumer costs. The results support the assumption that there is a need to develop and use additional and case-specific performance criteria for electricity load forecasting.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Engineering, Research group: Power systems, Research area: Power engineering, VTT Technical Research Centre of Finland, University of Eastern Finland
Contributors: Koponen, P., Ikäheimo, J., Koskela, J., Brester, C., Niska, H.
Publication date: 1 Apr 2020
Peer-reviewed: Yes

Publication information

Journal: Energies
Volume: 13
Issue number: 8
Article number: 2054
ISSN (Print): 1996-1073
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Energy (miscellaneous), Control and Optimization, Electrical and Electronic Engineering
Keywords: Cost analysis, Performance criteria, Power systems, Short term load forecasting
Electronic versions: 
Source: Scopus
Source ID: 85084049691

Research output: Contribution to journalArticleScientificpeer-review

Practical implementation of adaptive SRF-PLL for three-phase inverters based on sensitivity function and real-time grid-impedance measurements

Rapidly increasing demand for renewable energy has created a need for the photovoltaic and wind farms to be placed in various locations that have diverse and possibly time-variant grid conditions. A mismatch between the grid impedance and output admittance of an inverter causes impedance-based stability issues, which appear as power quality problems and poor transient performance. Grid synchronization with phase-locked loop (PLL) introduces a negative-resistance-like behavior to inverter output admittance. High control bandwidth of the PLL makes the system sensitive to impedance-based stability issues when the inverter is connected to a weak grid that has high impedance. However, very conservative tunings lead to overly damped dynamic responses in strong grids, where the control performance and power quality can be improved by applying higher PLL control bandwidths. Continuous evaluation of grid conditions makes it possible to avoid the risk of instability and poor dynamic responses, as the inverter output admittance can be re-shaped online to continuously match the grid conditions. The present work proposes method for adaptive control of the PLL based on the real-time measurements of the grid impedance, applying pseudo-random binary sequence (PRBS) injections. The method limits the PLL bandwidth in weak grids to avoid stability issues and increases the control bandwidth in strong grids to improve voltage-tracking, and thus overall control performance. The method is verified through simulations and experimental laboratory tests in a kW-scale system. The results show that optimizing the PLL bandwidth with respect to the grid conditions is highly beneficial for system performance and stability.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Automation Technology and Mechanical Engineering, Research group: Automation and Systems Theory, Electrical Engineering
Contributors: Luhtala, R., Alenius, H., Roinila, T.
Publication date: 1 Mar 2020
Peer-reviewed: Yes

Publication information

Journal: Energies
Volume: 13
Issue number: 5
Article number: 1173
ISSN (Print): 1996-1073
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Energy (miscellaneous), Control and Optimization, Electrical and Electronic Engineering
Keywords: Control systems, Impedance measurement, Phase locked loops, Power electronics, Stability analysis, System identification
Source: Scopus
Source ID: 85081124050

Research output: Contribution to journalArticleScientificpeer-review

A novel electrical charging condensing heat exchanger for efficient particle emission reduction in small wood boilers

Small-scale biomass combustion is an important source of fine particles in ambient air, causing adverse health and environmental effects. Thus, there is a clear need to develop efficient and feasible flue gas cleaning technologies for small-scale combustion appliances. In this study a novel electrical charging condensing heat exchanger (eCHX) for combined fine particle removal and efficient heat recovery from flue gases was demonstrated in a small biomass-fired boiler. The method is based on the combination of a shielded corona charger and a condensing heat exchanger, where fine particles are removed by the electrophoretic, thermophoretic and diffusiophoretic forces. The eCHX was found to decrease >80% of fine particle mass (PM1) emissions and >40% of particle number emissions with simultaneous high thermal efficiency in the heat exchanger. The usage of the condensing heat exchanger without electrical charging resulted in 40% decrease in PM1 emissions when compared to the usage of a traditional tube heat exchanger. The advantage of the eCHX system is that it replaces the conventional heat exchanger in boilers, making it a compact and inexpensive solution, when compared to additional flue gas cleaning devices installed after the boiler.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, University of Eastern Finland, Fine Particle and Aerosol Technology Laboratory, Tampere University of Applied Sciences
Contributors: Grigonytė-Lopez Rodriguez, J., Suhonen, H., Laitinen, A., Tissari, J., Kortelainen, M., Tiitta, P., Lähde, A., Keskinen, J., Jokiniemi, J., Sippula, O.
Number of pages: 9
Pages: 521-529
Publication date: Jan 2020
Peer-reviewed: Yes

Publication information

Journal: Renewable Energy
Volume: 145
ISSN (Print): 0960-1481
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment
Keywords: Biomass combustion, Electrical charging, Heat exchanger, Particle emission
Source: Scopus
Source ID: 85067517949

Research output: Contribution to journalArticleScientificpeer-review

Acid and ferric sulfate bioleaching of uranium ores: A review

This review examines the acid and ferric sulfate bioleaching of uranium from low grade ores. The review traces back the progression of the technology from the time the role of microorganisms was recognized in the 1950’s and 1960’s. Some past and present uranium mining operations with active or potential microbial contribution are summarized. Experimental techniques and laboratory bioleaching experiments are described. Choice microorganisms have been iron- and sulfur-oxidizing acidophiles, comprising bacteria and archaea with mesophilic and thermophilic temperature ranges. Uranium is bioleached from ores in acidic ferric sulfate lixiviant. Ferric iron oxidizes tetravalent uranium to the hexavalent form and is thereby reduced to ferrous iron in this redox reaction. Microorganisms in the bioleaching process oxidize ferrous iron to the ferric form and thus regenerate ferric sulfate. Iron oxidation requires oxygen as the electron acceptor in the leach solution. Acidity ensures that ferric iron is soluble in the lixiviant and protons increase the solubilization of the oxidized, hexavalent uranium. Ancillary sulfide minerals such as pyrite enhance the bioleaching because their oxidation releases ferrous iron and reduced sulfur compounds for biological ferric iron and sulfuric acid generation. The main mining engineering approaches used for uranium leaching are heap, dump, stope, in situ, and in-place leaching. The efficiency of uranium bioleaching is affected by a number of mineralogical, physicochemical, microbial and process factors. Bioinformatics and synthetic biology are progressing the research on bioleaching microorganisms but these developments have not been materialized in the industrial practice of uranium mining. New applications of uranium bioleaching may focus increasingly on deposits where other products such as rare earth elements or base metals can be recovered in addition to uranium.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Materials Science and Environmental Engineering, CSIRO Land and Water, University of Western Australia, Ohio State University
Contributors: Kaksonen, A. H., Lakaniemi, A., Tuovinen, O. H.
Number of pages: 25
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Journal of Cleaner Production
Volume: 264
Article number: 121586
ISSN (Print): 0959-6526
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Environmental Science(all), Strategy and Management, Industrial and Manufacturing Engineering
Keywords: Acidophilic microorganisms, Bioleaching, Iron oxidation, Sulfur oxidation, Uranium mining

Bibliographical note

EXT="Kaksonen, Anna H."
EXT="Tuovinen, Olli H."

Source: Scopus
Source ID: 85084258453

Research output: Contribution to journalReview ArticleScientificpeer-review

Autonomous reactive power support for smart photovoltaic inverter based on real-time grid-impedance measurements of a weak grid

A large share of renewable energy production is connected to a weak grid with significant grid impedance. The transmission impedance causes unintended flow of reactive power to grid, coupling the grid reactive power to the active power fed from the inverter. The reactive power causes transmission losses, strains the grid with reactive power requirements, and can even compromise system stability. Requirements on reactive power support were recently imposed on new photovoltaic inverters, which are often implemented with proportional power factor control or droop control for local voltage regulation. The present work proposes a method for real-time compensation of the unintended reactive power, which decouples the reactive power from the active power of a photovoltaic inverter. Based on real-time measurement of the grid impedance, the unintended reactive power is estimated and autonomously compensated in the inverter. The method removes the fluctuating reactive power component, while still permitting unrestricted manual control of the reactive power. Unlike conventional methods, the proposed method requires no prior knowledge on grid impedance values or delicate tuning. The method outperforms conventional power factor control even when the conventional method is tuned optimally with known grid inductance. The method is validated with simulations and experiments on three-phase photovoltaic inverter connected to a weak grid.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Engineering, Research group: Power electronics, Automation Technology and Mechanical Engineering, Research group: Automation and Systems Theory, Research area: Power engineering
Contributors: Alenius, H., Luhtala, R., Messo, T., Roinila, T.
Number of pages: 14
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Electric Power Systems Research
Volume: 182
Article number: 106207
ISSN (Print): 0378-7796
Original language: English
ASJC Scopus subject areas: Energy Engineering and Power Technology, Electrical and Electronic Engineering
Keywords: Photovoltaic systems, Power conditioning, Power electronics, Power flow optimization, Reactive power control
Source: Scopus
Source ID: 85078163091

Research output: Contribution to journalArticleScientificpeer-review

Censor-Based Cooperative Multi-Antenna Spectrum Sensing with Imperfect Reporting Channels

The present contribution proposes a spectrally efficient censor-based cooperative spectrum sensing (C-CSS) approach in a sustainable cognitive radio network that consists of multiple antenna nodes and experiences imperfect sensing and reporting channels. In this context, exact analytic expressions are first derived for the corresponding probability of detection, probability of false alarm, and secondary throughput, assuming that each secondary user (SU) sends its detection outcome to a fusion center only when it has detected a primary signal. Capitalizing on the findings of the analysis, the effects of critical measures, such as the detection threshold, the number of SUs, and the number of employed antennas, on the overall system performance are also quantified. In addition, the optimal detection threshold for each antenna based on the Neyman-Pearson criterion is derived and useful insights are developed on how to maximize the system throughput with a reduced number of SUs. It is shown that the C-CSS approach provides two distinct benefits compared with the conventional sensing approach, i.e., without censoring: i) the sensing tail problem, which exists in imperfect sensing environments, can be mitigated; and ii) less SUs are ultimately required to obtain higher secondary throughput, rendering the system more sustainable.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Wireless Communications and Positioning, Electrical Engineering, Taiyuan University of Science and Technology, University of Waterloo, Khalifa University, University of Surrey, University of London, Simon Fraser University
Contributors: Li, M., Alhussein, O., Sofotasios, P. C., Muhaidat, S., Yoo, P. D., Liang, J., Wang, A.
Number of pages: 13
Pages: 48-60
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: IEEE Transactions on Sustainable Computing
Volume: 5
Issue number: 1
ISSN (Print): 2377-3782
Original language: English
ASJC Scopus subject areas: Computational Theory and Mathematics, Hardware and Architecture, Software, Renewable Energy, Sustainability and the Environment, Control and Optimization
Keywords: censoring, cooperative spectrum sensing, energy detection, energy efficiency, imperfect reporting channels, multi-antenna systems, Sustainble computing
Source: Scopus
Source ID: 85081759371

Research output: Contribution to journalArticleScientificpeer-review

Charge transfer characteristics of fullerene-free polymer solar cells via multi-state electronic coupling treatment

Recently, non-fullerene (NF) polymer solar cells (PSCs), where new electron acceptor (eA) materials are blended with a donor-acceptor (D-A) copolymer as an electron donor (eD), have shown promising power conversion efficiencies up to 18%. Some of the best-performing NF PSCs use the eD copolymers PBDT-TzBI, PDTB-EF-T, and PBDB-T-2F, and either a D-A copolymer P(NDI2OD-T2) or small molecule acceptors (SMAs) ITIC-4F and ITIC-2Cl as the NF eA compounds. Here we investigate these systems with density functional theory methods and extend our previous study of the multi-state fragment charge difference (FCD) electronic coupling scheme by applying it to the calculations of charge transfer (CT) rates for exciton dissociation and charge recombination (CR) processes at local eD-eA interfaces. Despite similar backbone structures and optical properties, the studied eD copolymers have different conformational, ionization, excitation, and CT characteristics. The electronic couplings and CT rates depend strongly on the relative positioning of the eD and eA compounds in the eD-eA complexes. While the main CT path is from eD to the eA compound, CT from eA to the eD compound is also predicted in the polymer-polymer PBDT-TzBI-P(NDI2OD-T2) system. The multi-state FCD electronic couplings are independent of the number of the excited states included in the calculations when using a dispersion-corrected optimally tuned long-range corrected functional. The calculated CR rates are slower in the polymer-SMA systems than in the polymer-polymer system, which could partly account for their higher experimentally observed efficiencies in devices.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Chemistry & Advanced Materials
Contributors: Kastinen, T., Hukka, T. I.
Number of pages: 21
Pages: 4137-4157
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Sustainable Energy and Fuels
Volume: 4
Issue number: 8
ISSN (Print): 2398-4902
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Energy Engineering and Power Technology
Source: Scopus
Source ID: 85089201008

Research output: Contribution to journalArticleScientificpeer-review

Charlie and the CryptoFactory: Towards Secure and Trusted Manufacturing Environments

The modernization that stems from Industry 4.0 started populating the manufacturing sector with networked devices, complex sensors, and a significant proportion of physical actuation components. However, new capabilities in networked cyber-physical systems demand more complex infrastructure and algorithms and often lead to new security flaws and operational risks that increase the attack surface area exponentially. The interconnected nature of Industry 4.0-driven operations and the pace of digital transformation mean that cyberattacks can have far more extensive effects than ever before. Based on that, the core ideas of this paper are driven by the observation that cybersecurity is one of the key enablers of Industry 4.0. Having this in mind, we propose CryptoFactory - a forward-looking design of a layered-based architecture that can be used as a starting point for building secure and privacy-preserving smart factories. CryptoFactory aims to change the security outlook in smart manufacturing by discussing a set of fundamental requirements and functionality that modern factories should support in order to be resistant to both internal and external attacks. To this end, CryptoFactory first focuses on how to build trust relationships between the hardware devices in the factory. Then, we look on how to use several cryptographic approaches to allow IoT devices to securely collect, store and share their data while we also touch upon the emerging topic of secure and privacy-preserving communication and collaboration between manufacturing environments and value chains. Finally, we look into the problem of how to perform privacy-preserving analytics by leveraging Trusted Execution Environments and the promising concept of Functional Encryption.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Computing Sciences, University of Westminster
Contributors: Michalas, A., Kiss, T.
Number of pages: 6
Pages: 141-146
Publication date: 2020

Host publication information

Title of host publication: 20th IEEE Mediterranean Electrotechnical Conference, MELECON 2020 : Proceedings
Publisher: IEEE
ISBN (Print): 978-1-7281-5201-1
ISBN (Electronic): 9781728152004

Publication series

Name: IEEE Mediterranean Electrotechnical Conference
Publisher: Institute of Electrical and Electronics Engineers
ISSN (Print): 2158-8473
ISSN (Electronic): 2158-8481
ASJC Scopus subject areas: Control and Systems Engineering, Electrical and Electronic Engineering, Control and Optimization, Information Systems and Management, Energy Engineering and Power Technology
Keywords: Industry 4.0, Privacy, Security, Smart Factories

Bibliographical note

JUFOID=72875

Source: Scopus
Source ID: 85089274465

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Distributed small loads as fast frequency reserves: Impact on system performance

This paper discusses the concept of using AMR (automatic meter reading) connected distributed loads as fast frequency reserves (ACFRs). The paper presents high-level analysis on power system response when considerable amount of directly grid-connected rotational reserves are replaced by AMR meter connected loads. In the study, the amount of ACFRs and their response time (i.e. very fast and fast) are varied together with different rotational kinetic reserves of power generation participating in frequency control. For the studies, a general power system and load models for EMT-type software have been established. The results show that ACFR could in principle replace effectively rotating reserves provided that frequency measurement and the coordination of the ACFRs are robust. The studied load shedding patterns and parametrization have less than excepted influence on frequency minimum and system response.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Engineering, Research group: Power systems, Fingrid Oyj
Contributors: Peltonen, L., Järventausta, P., Repo, S., Rauhala, T.
Number of pages: 6
Pages: 114-119
Publication date: 2020

Host publication information

Title of host publication: 2020 IEEE Texas Power and Energy Conference, TPEC 2020
Publisher: IEEE
ISBN (Electronic): 9781728144368
ASJC Scopus subject areas: Computer Networks and Communications, Energy Engineering and Power Technology, Electrical and Electronic Engineering, Safety, Risk, Reliability and Quality
Keywords: AMR, Distributed load, Fast frequency reserves, Measurement, Power system

Bibliographical note

EXT="Rauhala, Tuomas"

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Enhancement of EQE for MBE grown InAs/GaAs Quantum Dot Solar Cell with Back Reflector

We report on molecular beam epitaxy grown InAs/GaAs quantum dot solar cells incorporating thin-film configuration with back surface reflectors. External quantum efficiency measurements reveal two times higher current generation for the quantum dots with the thin-film solar cell with the back reflector compared to a standard reference solar cell without back reflector. A high open-circuit voltage of 0.884 V is demonstrated. Furthermore, the benefits of using more advanced designs for a back reflector employing pyramidal diffraction gratings are discussed.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Physics, Research group: ORC, Politecnico di Torino
Contributors: Aho, T., Tukiainen, A., Ranta, S., Elsehrawy, F., Raappana, M., Isoaho, R., Aho, A., Cappelluti, F., Guina, M.
Number of pages: 4
Pages: 2593-2596
Publication date: 2020

Host publication information

Title of host publication: 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC)
Publisher: IEEE
ISBN (Electronic): 978-1-7281-0494-2

Publication series

Name: Conference record of the IEEE Photovoltaic Specialists Conference
ISSN (Print): 0160-8371
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Materials Science (miscellaneous)
Keywords: Solar Cell, Semiconducting III-V Materials

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Enhancing thermophilic dark fermentative hydrogen production at high glucose concentrations via bioaugmentation with Thermotoga neapolitana

The aim of the present study was to investigate the effect of gradually increasing glucose concentrations (from 5.6 to 111 mmol L−1) on the fermentative H2 production with and without bioaugmentation. A stirred tank reactor (STR) was operated at 70 °C and inoculated with a hyperthermophilic mixed culture or a hyperthermophilic mixed culture bioaugmented with Thermotoga neapolitana. With both the unaugmented (control) and augmented cultures, the H2 production rate was improved when the initial glucose concentration was increased. In contrast, the highest H2 yield (1.68 mol H2 mol−1 glucose consumed) was obtained with the augmented culture at the lowest glucose concentration of 5.6 mmol L−1 and was 37.5% higher than that obtained with the unaugmented culture at the same feed glucose concentration. Overall, H2 production rates and yields were higher in the bioaugmented cultures than in the unaugmented cultures whatever the glucose concentration. Quantitative polymerase chain reaction targeting T. neapolitana hydA gene and MiSeq sequencing proved that Thermotoga was not only present in the augmented cultures but also the most abundant at the highest glucose concentrations.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Bio- and Circular Economy, Materials Science and Environmental Engineering, ENEA/CREATE/Università Degli Studi Napoli Federico II, INRA
Contributors: Okonkwo, O., Papirio, S., Trably, E., Escudie, R., Lakaniemi, A., Esposito, G.
Number of pages: 9
Pages: 17241-17249
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: International Journal of Hydrogen Energy
Volume: 45
Issue number: 35
ISSN (Print): 0360-3199
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Condensed Matter Physics, Energy Engineering and Power Technology
Keywords: Biohydrogen, Dark fermentation, Metabolic pathways, Microbial dynamics

Bibliographical note

EXT="Papirio, Stefano"

Source: Scopus
Source ID: 85085051125

Research output: Contribution to journalArticleScientificpeer-review

Hematite Surface Modification toward Efficient Sunlight-Driven Water Splitting Activity: The Role of Gold Nanoparticle Addition

Localized surface plasmon resonance has been investigated to enhance light harvesting in hematite-based photoelectrodes modified with gold nanoparticles (AuNPs); meanwhile, an extensive understanding about the different processes involved in the hematite-AuNP system remains unclear. This work addresses a majority of effects associated with AuNP addition by comparing charge transfer, catalytic and light harvesting efficiencies. The obtained results revealed that the lower AuNP amount leads to a higher photocurrent response of 1.20 mA cm-2 at 1.23 VRHE in comparison with all photoelectrodes designed here. X-ray photoelectron data revealed that hematite photoelectrodes loaded with higher concentrations of AuNPs immersed in an alkaline electrolyte showed hydrated/oxidized gold phase formation at the electrode/electrolyte interface. This change on the semiconductor-metal interface may affect the conductivity impairing the photocatalytic performance because of the passivation layer on the AuNP surface, decreasing the efficiency of charge transfer. Notoriously, increasing AuNP amount supported on the hematite surface clearly promoted higher light absorption, which was surprisingly not followed by photoelectrochemical efficiency. This result suggests here that the plasmon effect is not a dominant phenomenon that drives the photoelectrode performance. In fact, a deeper analysis showed that the loaded hematite photoelectrodes with low amounts of AuNPs provides a Schottky contact at the semiconductor-metal interface leading to Fermi level equilibration enhancing charge transport efficiency, which is classified as the predominant effect leading to higher photoresponse in the system.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Universidade Federal do ABC, Microscopy Centre
Contributors: Tofanello, A., Freitas, A. L., Carvalho, W. M., Salminen, T., Niemi, T., Souza, F. L.
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
ISSN (Print): 1932-7447
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Energy(all), Physical and Theoretical Chemistry, Surfaces, Coatings and Films
Source: Scopus
Source ID: 85082009064

Research output: Contribution to journalArticleScientificpeer-review

Local Mechanical Properties at the Dendrite Scale of Ni-Based Superalloys Studied by Advanced High Temperature Indentation Creep and Micropillar Compression Tests

Chemical inhomogenities due to dendritic solidification of Ni-based superalloys result in different local microstructures with varying mechanical properties. New indentation creep test methods allow probing of the local creep properties at the dendrite scale at high temperatures. The as-cast single crystalline Ni-based superalloy ERBO1A (a derivative alloy of CMSX–4) was investigated and electron-probe microanalysis (EPMA) measurements revealed strong segregation of, e.g., Re and W in the dendritic region and, e.g., Ta in the interdendritic region. Indentation creep experiments at 750 °C and micropillar compression tests at 785 °C were conducted in both regions, and a higher creep strength was found in the dendritic region compared to the interdendritic region. Theoretical models for solid solution hardening as well as γ′ precipitation hardening confirm these results, since they predict a higher strength in the dendritic region than in the interdendritic region. Compared with the fully heat treated state, a smaller difference in the local mechanical properties or even a reverse strength ratio of the dendritic and interdendritic region can be expected.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Materials Science and Environmental Engineering, Research group: Materials Characterization, Friedrich-Alexander-Universität Erlangen-Nürnberg, Swiss Federal Laboratories for Materials Science and Technology, Fraunhofer Institut für Keramische Technologien und Systeme
Contributors: Haußmann, L., Neumeier, S., Kolb, M., Ast, J., Mohanty, G., Michler, J., Göken, M.
Number of pages: 9
Pages: 273-281
Publication date: 2020

Host publication information

Title of host publication: Superalloys 2020 : Proceedings of the 14th International Symposium on Superalloys
Publisher: Springer
Editors: Tin, S., Hardy, M., Clews, J., Cormier, J., Feng, Q., Marcin, J., O'Brien, C., Suzuki, A.
ISBN (Print): 9783030518332
ISBN (Electronic): 978-3-030-51834-9

Publication series

Name: The Minerals, Metals and Materials Series
ISSN (Print): 2367-1181
ISSN (Electronic): 2367-1696
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Energy Engineering and Power Technology, Mechanics of Materials, Metals and Alloys, Materials Chemistry
Keywords: Dendritic segregations, Indentation creep, Micropillar compression, Ni-based superalloy

Bibliographical note

JUFOID=86210

Source: Scopus
Source ID: 85091283715

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Luminescent (Er,Ho)2O3 thin films by ALD to enhance the performance of silicon solar cells

We have fabricated luminescent (Er,Ho)2O3 thin films by atomic layer deposition (ALD) and studied their capability to enhance the performance of state-of-the-art single-junction c-Si bifacial solar cells. The films convert IR photons (e.g. 1523 nm) by three- and two-photon upconversion process to emit visible-light in the 400–700 nm range. When the films were coupled with solar cells, ~3% improvement in the short-circuit current density (620 ± 5 to 638 ± 5 mAcm−2) was recorded under a simulated solar excitation equivalent to 16 suns. These findings highlight a potential of ALD for the design and fabrication of luminescent coatings for practical solar cell devices.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Research group: ORC, Aalto University, University of Turku
Contributors: Ghazy, A., Safdar, M., Lastusaari, M., Aho, A., Tukiainen, A., Savin, H., Guina, M., Karppinen, M.
Number of pages: 5
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Solar Energy Materials and Solar Cells
Volume: 219
Article number: 110787
ISSN (Print): 0927-0248
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Renewable Energy, Sustainability and the Environment, Surfaces, Coatings and Films
Keywords: Atomic layer deposition, c-Si solar cell, Luminescence, Photonics, Upconversion
Source: Scopus
Source ID: 85090731507

Research output: Contribution to journalArticleScientificpeer-review

Mapping the types of business experimentation in creating sustainable value: A case study of cleantech start-ups

In this study, business experimentation for sustainable value creation is explored through seven cleantech start-ups by applying the systemic combining approach. The findings reveal novel descriptions of six different business experimentation types. The study also advances our theoretical understanding of how the specific roles of learning, signaling, and convincing dominate each of the experimentation types differently and how each type of business experimentation has a distinct purpose. Furthermore, our findings propose how business experimentation types can be applied as a continuum as part of the cleantech start-ups’ sustainable value creation process. Hence, our study contributes theoretically to our understanding of business experimentation for sustainable value creation and how the different types are applied in cleantech start-ups. We conclude our treatise with managerial implications and outline fruitful future research avenues.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Industrial Engineering and Management, Research group: Center for Innovation and Technology Research, Aarhus Universitet, Jönköping International Business School
Contributors: Aagaard, A., Saari, U. A., Mäkinen, S. J.
Number of pages: 12
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Journal of Cleaner Production
Volume: 279
Article number: 123182
ISSN (Print): 0959-6526
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Environmental Science(all), Strategy and Management, Industrial and Manufacturing Engineering
Keywords: Business experimentation, Cleantech, Start-up, Sustainable entrepreneurship, Sustainable value creation

Bibliographical note

EXT="Saari, Ulla A."

Source: Scopus
Source ID: 85089808603

Research output: Contribution to journalArticleScientificpeer-review

Modification of Surface States of Hematite-Based Photoanodes by Submonolayer of TiO2for Enhanced Solar Water Splitting

Surface states are inherently involved with photoelectrochemical (PEC) solar fuel production; some of them are beneficial and participate in the surface reactions, but some act as recombination centers and therefore limit the PEC efficiency. Surface treatments have been applied to modify the surface states, but interrelated effects of the treatments on both types of surface states have not been properly considered. This research examines the modification of the surface states on hematite-based photoanodes by atomic layer deposition of submonolayer amount of TiO2 and by postannealing treatments. Our results show that the postannealing causes diffusion of Ti deeper into the hematite surface layers, which leads to an increased saturation photocurrent and an anodic shift in the photocurrent onset potential. Without postannealing, the separate TiO2 phase on the hematite surface results in a second intermediate surface state and delayed charge carrier dynamics, i.e., passivation of the recombination surface states. It is evident by these results that the intermediate surface states observed with impedance spectroscopy in a PEC cell are directly involved in the surface reaction and not with the recombination surface states observed with ultrafast (picoseconds-nanoseconds) transient absorption spectroscopy in air. These results open new optimization strategies to control the beneficial and detrimental surface states independently.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Surface Science, Physics, Materials Science and Environmental Engineering, Chemistry and Advanced Materials Group
Contributors: Palmolahti, L., Ali-Löytty, H., Khan, R., Saari, J., Tkachenko, N. V., Valden, M.
Number of pages: 8
Pages: 13094-13101
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 124
Issue number: 24
ISSN (Print): 1932-7447
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Energy(all), Physical and Theoretical Chemistry, Surfaces, Coatings and Films
Source: Scopus
Source ID: 85088902594

Research output: Contribution to journalArticleScientificpeer-review

Numerical modeling of the tool-rock penetration process using FEM coupled with SPH technique

The numerical simulation of penetration into rock is an important tool to gain insights into rock drilling mechanisms, since it can be exploited as an alternative to the expensive field testing. This research aims to present an innovative computer simulation of rock penetration process on the basis of the finite element method (FEM) coupled with smoothed particle hydrodynamics (SPH). An advanced material model, namely the Karagozian and Case Concrete (KCC) model, was employed for this purpose. The Punch Penetration test (PPT) was carried out on a medium strength sandstone for validating the numerical method. The comparison of the numerical and experimental results obtained concluded that the FEM coupled with SPH method in conjunction with the fully calibrated KCC material model is a reliable method for the study of rock penetration due to its ability to deal with large deformations and its realistic constitutive modeling. The modeling approach was finally applied to estimate the required force to penetrate an offshore reservoir rock block under the in-situ confining pressure with a double conical tool up to 5 mm depth. The effective stresses in sedimentary basins of Agosta and Dosso Campus at a depth of 3000 m below the seabed are considered as the confining pressures of this study.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Research group: Structural Mechanics, Politecnico di Milano
Contributors: Mardalizad, A., Saksala, T., Manes, A., Giglio, M.
Number of pages: 14
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
Volume: 189
Article number: 107008
ISSN (Print): 0920-4105
Original language: English
ASJC Scopus subject areas: Fuel Technology, Geotechnical Engineering and Engineering Geology
Keywords: Coupled FEM-SPH, Drilling, KCC, Punch penetration test (PPT)
Source: Scopus
Source ID: 85078782491

Research output: Contribution to journalArticleScientificpeer-review

Plant-Based Biodegradable Capacitive Tactile Pressure Sensor Using Flexible and Transparent Leaf Skeletons as Electrodes and Flower Petal as Dielectric Layer

In biomedical sciences, there is demand for electronic skins with highly sensitive tactile sensors, having applications in patient monitoring, human–machine interfaces, and on-body sensors. In clinical applications, it would be especially beneficial if the sensors would be disposable. Here, an all plant-material-based biodegradable capacitive tactile pressure sensor for disposable electronic skins is reported. Silver-nanowire-coated leaf skeletons are used as breathable and flexible electrodes while freeze-dried rose petals are used as the dielectric layer. The leaf skeleton electrodes have a rough fractal-like architecture, which provides good adhesion to the silver nanowires and maintains interconnections between the silver nanowires when the electrodes are bent. The electrodes display low constant resistance up to curvature of 800 m−1. The rose petal dielectric layer has a multiscale 3D cell wall microstructure, which compresses elastically when subjected to pressure. The fabricated sensor can respond to pressures ranging from 0.007 to at least 60 kPa, with a maximum sensitivity of ≈0.08 kPa−1. The signal is stable for at least 5000 pressure cycles, after an initial break-in period. Owing to the all biomaterial constituents, the sensor is biodegradable under aqueous conditions. The sensor is successfully applied as an e-skin in touch sensing and gesture monitoring.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: BioMediTech
Contributors: Elsayes, A., Sharma, V., Yiannacou, K., Koivikko, A., Rasheed, A., Sariola, V.
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Advanced Sustainable Systems
ISSN (Print): 2366-7486
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Environmental Science(all)
Keywords: bioinspiration, capacitive sensors, electronic skins, leaf skeletons
Electronic versions: 
Source: Scopus
Source ID: 85085072940

Research output: Contribution to journalArticleScientificpeer-review

Structural Compatibility of Infrastructures Utilizing Alternative Earth Construction Materials

This paper presents analysis of the structural behavior of road pavements in which alternative construction materials are replacing the traditional ones in some of the structural layers. The analysis is consider important since from the structural performance point of view many of the alternative materials have mechanical properties far different from those of the traditional road construction materials, especially unbound aggregates, and as a consequence of that, the empirically calibrated design rules applied and adjusted for the normally utilized pavements solutions are not valid any more. The analysis is exemplified by means of four different low volume road pavement structures that are in line with the existing design guidelines in Finland. The mechanical behavior of these structures is analyzed using three different approaches: semi-empirical Oedemark design approach, multi-layer linear elastic analysis and finite element analysis. The obtained calculation results indicate clearly that if a low volume road structure containing a high stiffness layer made e.g. of stabilized fly ash is resting on soft subgrade soil, tensile stresses up to 1 MPa may be developed. Therefore, the performance and respective distress mechanisms of the structure are likely to be very different from those of a traditional solution. As a key conclusion from the analysis, need for a new concept, structural compatibility, was identified. It would help in drawing due attention to the mechanical behavior of alternative materials when they are used in replacing the traditional ones in road structures exposed to repeated heavy traffic loads. Graphic Abstract: [Figure not available: see fulltext.].

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Research group: Earth Constructions, Research area: Infrastructure Construction
Contributors: Kolisoja, P., Kalliainen, A.
Number of pages: 9
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Waste and Biomass Valorization
ISSN (Print): 1877-2641
Original language: English
ASJC Scopus subject areas: Environmental Engineering, Renewable Energy, Sustainability and the Environment, Waste Management and Disposal
Keywords: Alternative material, Mechanical behavior, Road pavement, Structural compatibility
Source: Scopus
Source ID: 85083433907

Research output: Contribution to journalArticleScientificpeer-review

Urban housing density and infrastructure costs

Urbanisation is one of the most significant global megatrends and, as a result, major cities are facing multiple challenges. In this study, we contribute to the sustainable urban development debate and examine the relation between housing density and infrastructure costs. The analysis is based on four hypothetical design prototypes and a consistent cost calculation framework. Based on the results, infrastructure costs per capita are the highest in low-density areas and the lowest in high-density areas, if parking is excluded. However, if also construction costs of parking structures are included, the costs per capita are the highest in high-density areas. Considering the notably high cost impact of parking structures and people's limited willingness to pay for parking, municipally zoned parking requirements in urban areas are likely to result in non-optimal land use. Furthermore, construction in poor soil conditions may only be considered feasible if the floor area ratio and residential densities are relatively high. Beyond the cost benefits, the number of residents that may be accommodated is crucial and higher density in central urban locations should be promoted. We also suggest the cost of urban greenness to be reasonable relative to its many reported benefits and conclude that denser urban structure should not be pursued at the expense of green spaces.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Research group: Responsible Construction
Contributors: Kurvinen, A., Saari, A.
Number of pages: 24
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Sustainability (Switzerland)
Volume: 12
Issue number: 2
Article number: 497
ISSN (Print): 2071-1050
Original language: English
ASJC Scopus subject areas: Geography, Planning and Development, Renewable Energy, Sustainability and the Environment, Management, Monitoring, Policy and Law
Keywords: Floor area ratio, Green spaces, Infrastructure costs, Parking, Residential density, Urban housing density
Electronic versions: 
Source: Scopus
Source ID: 85079605222

Research output: Contribution to journalArticleScientificpeer-review

Power production and microbial community composition in thermophilic acetate-fed up-flow and flow-through microbial fuel cells

The microbial communities developed from a mixed-species culture in up-flow and flow-through configurations of thermophilic (55 °C) microbial fuel cells (MFCs), and their power production from acetate, were investigated. The up-flow MFC was operated for 202 days, obtaining an average power density of 0.13 W/m3, and Tepidiphilus was the dominant transcriptionally-active microorganisms. The planktonic community developed in the up-flow MFC was used to inoculate a flow-through MFC resulting in the proliferation of Ureibacillus, whose relative abundance increased from 1 to 61% after 45 days. Despite the differences between the up-flow and flow-through MFCs, including the anode electrode, hydrodynamic conditions, and the predominant microorganism, similar (p = 0.05) volumetric power (0.11–0.13 W/m3), coulombic efficiency (16–18%) and acetate consumption rates (55–69 mg/L/d) were obtained from both. This suggests that though MFC design can shape the active component of the thermophilic microbial community, the consortia are resilient and can maintain similar performance in different MFC configurations.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Bio- and Circular Economy, Natl. University of Ireland, Galway, Indian Institute of Technology Hyderabad
Contributors: Dessì, P., Chatterjee, P., Mills, S., Kokko, M., Lakaniemi, A., Collins, G., Lens, P. N.
Publication date: 1 Dec 2019
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 294
Article number: 122115
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2019): CiteScore 12.8 SJR 2.43 SNIP 2.012
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Renewable Energy, Sustainability and the Environment, Waste Management and Disposal
Keywords: Attached community, Bioelectrochemical system, Electrogenic microorganisms, MFC, Microbial electrochemical technology, Planktonic community
Source: Scopus
Source ID: 85072279751

Research output: Contribution to journalArticleScientificpeer-review

Towards the EU emission targets of 2050: Cost-effective emission reduction in Finnish detached houses

To mitigate the effects of climate change, the European Union calls for major carbon emission reductions in the building sector through a deep renovation of the existing building stock. This study examines the cost-effective energy retrofit measures in Finnish detached houses. The Finnish detached house building stock was divided into four age classes according to the building code in effect at the time of their construction. Multi-objective optimization with a genetic algorithm was used to minimize the life cycle cost and CO2 emissions in each building type for five different main heating systems (district heating, wood/oil boiler, direct electric heating, and ground-source heat pump) by improving the building envelope and systems. Cost-effective emission reductions were possible with all heating systems, but especially with ground-source heat pumps. Replacing oil boilers with ground-source heat pumps (GSHPs), emissions could be reduced by 79% to 92% across all the studied detached houses and investment levels. With all the other heating systems, emission reductions of 20% to 75% were possible. The most cost-effective individual renovation measures were the installation of air-to-air heat pumps for auxiliary heating and improving the thermal insulation of external walls.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Research group: Responsible Construction, Aalto University
Contributors: Hirvonen, J., Jokisalo, J., Heljo, J., Kosonen, R.
Number of pages: 29
Publication date: 19 Nov 2019
Peer-reviewed: Yes

Publication information

Journal: Energies
Volume: 12
Issue number: 22
Article number: 4395
ISSN (Print): 1996-1073
Ratings: 
  • Scopus rating (2019): CiteScore 3.8 SJR 0.635 SNIP 1.154
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Energy (miscellaneous), Control and Optimization, Electrical and Electronic Engineering
Keywords: Deep renovation, Detached house, Energy retrofit, Genetic algorithm, Greenhouse gas emissions, Heat pump, Multi-objective optimization
Electronic versions: 
Source: Scopus
Source ID: 85076020206

Research output: Contribution to journalArticleScientificpeer-review

Potential of renewable fuel to reduce diesel exhaust particle emissions

The use of fossil fuels in traffic is a significant source of air pollutants and greenhouse gases in rapidly growing and densely populated cities. Diesel exhaust emissions including particle number concentration and size distribution along with the particles’ chemical composition and NOx were investigated from a Euro 4 passenger car with a comprehensive set of high time-resolution instruments. The emissions were compared with three fuel standards – European diesel (EN590), Indian diesel (BS IV) and Finnish renewable diesel (Neste MY) – over the New European Driving Cycle (NEDC) and the Worldwide harmonized Light vehicles Test Cycle (WLTC). Fuel properties and driving conditions strongly affected exhaust emissions. The exhaust particulate mass emissions for all fuels consisted of BC (81–88%) with some contribution from organics (11–18%) and sulfate (0–3%). As aromatic-free fuel, the MY diesel produced around 20% lower black carbon (BC) emissions compared to the EN590 and 29–40% lower compared to the BS IV. High volatile nanoparticle concentrations at high WLTC speed conditions were observed with the BS IV and EN590 diesel, but not with the sulfur-free MY diesel. These nanoparticles were linked to sulfur-driven nucleation of new particles in cooling dilution of the exhaust. For all the fuels non-volatile nanoparticles in sub-10 nm particle sizes were observed during engine braking, and they were most likely formed from lubricant-oil-originated compounds. With all the fuels, the measured particulate and NOx emissions were significantly higher during the WLTC cycle compared to the NEDC cycle. This study demonstrated that renewable diesel fuels enable mitigations of particulate and climate-warming BC emissions of traffic, and will simultaneously help tackle urban air quality problems.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Department of Automotive and Mechanical Engineering, Metropolia University of Applied Sciences, Finnish Meteorological Institute, The Energy and Resources Institute India, Neste Oyj
Contributors: Pirjola, L., Kuuluvainen, H., Timonen, H., Saarikoski, S., Teinilä, K., Salo, L., Datta, A., Simonen, P., Karjalainen, P., Kulmala, K., Rönkkö, T.
Publication date: 15 Nov 2019
Peer-reviewed: Yes

Publication information

Journal: Applied Energy
Volume: 254
Article number: 113636
ISSN (Print): 0306-2619
Ratings: 
  • Scopus rating (2019): CiteScore 16.4 SJR 3.607 SNIP 2.865
Original language: English
ASJC Scopus subject areas: Building and Construction, Energy(all), Mechanical Engineering, Management, Monitoring, Policy and Law
Keywords: Black carbon, Combustion, New European Driving Cycle, Renewable fuel, Traffic emissions, Worldwide harmonized Light vehicles Test Cycle
Electronic versions: 

Bibliographical note

EXT="Pirjola, Liisa"

Source: Scopus
Source ID: 85070211798

Research output: Contribution to journalArticleScientificpeer-review

Maximum perturbation step size in MPP-Tracking control for ensuring predicted PV power settling behavior

The heuristic perturb-and-observe-based maximum-power-point tracking (MPPT) algorithm of photovoltaic (PV) generator is still the most popular technique in use, despite the broad spectrum of developed other MPPT algorithms. The correct direction of the next perturbation step requires that the previous perturbation is settled down properly and the applied perturbation step size is large enough to overcome the PV-power changes induced by the varying irradiation level and/or the power-grid-originated PV-voltage ripple. The requirements for the minimum perturbation step size are well defined in the available literature. The design equations to predict the PV-power settling time are derived by assuming that the PV-interfacing converter operates in continuous conduction mode (CCM). A large perturbation step size may drive the interfacing converter to enter into discontinuous conduction mode (DCM), which will delay the PV-power settling process and destroy the validity of the predicted settling times. In order to avoid confusing the MPPT process, the maximum perturbation step size has to be limited as well. This paper provides theoretical foundations for the proper design of the maximum step size based on the DC-DC interfacing-converter dynamic behavior. The theoretical findings are validated with experiments as well as by simulations by means of a boost-type DC-DC converter and real PV panel.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Engineering, Research group: Power electronics, Research area: Power engineering, Ben-Gurion University of the Negev
Contributors: Suntio, T., Kuperman, A.
Number of pages: 19
Publication date: 19 Oct 2019
Peer-reviewed: Yes

Publication information

Journal: Energies
Volume: 12
Issue number: 20
Article number: 3984
ISSN (Print): 1996-1073
Ratings: 
  • Scopus rating (2019): CiteScore 3.8 SJR 0.635 SNIP 1.154
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Energy (miscellaneous), Control and Optimization, Electrical and Electronic Engineering
Keywords: MPP tracking, Perturbation step size, PV generator, Transient settling time
Electronic versions: 
Source: Scopus
Source ID: 85075001066

Research output: Contribution to journalArticleScientificpeer-review

Performance of Solar Cell Grids based on Ag, Au, and Al for Cost-Effective Manufacturing

We report on the performance of contact grids based on Ag, Al, and Au applied to III-V multijunction solar cells. We compare their their suitability as grid metals from different perspectives, including price, mass-to-conductivity ratio, and abundance. The grid functionality was evaluated by performing charge transport experiments under simulated sunlight. The best solar cell performance was obtained for Ag contacts. On the other hand, Al and Ag provide the most cost-effective approach: when compared to Au for equal conductivities, the cost for the grid material being only about 1.1% in the case of Ag, and 0.7% for Al.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Physics, Research group: ORC
Contributors: Raappana, M., Aho, A., Aho, T., Isoaho, R., Anttola, E., Kajas, N., Polojärvi, V., Tukiainen, A., Guina, M.
Publication date: Oct 2019

Host publication information

Title of host publication: 2019 European Space Power Conference (ESPC)
Publisher: IEEE
ISBN (Print): 978-1-7281-2127-7
ISBN (Electronic): 978-1-7281-2126-0
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Renewable Energy, Sustainability and the Environment
Keywords: Solar Cell, Semiconducting III-V Materials

Bibliographical note

INT=PHYS, "Anttola, Elina"
INT=PHYS, "Kajas, Ninja"

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Building university-industry co-innovation networks in transnational innovation ecosystems: Towards a transdisciplinary approach of integrating social sciences and artificial intelligence

This paper presents a potential solution to fill a gap in both research and practice that there are few interactions between transnational industry cooperation (TIC) and transnational university cooperation (TUC) in transnational innovation ecosystems. To strengthen the synergies between TIC and TUC for innovation, the first step is to match suitable industrial firms from two countries for collaboration through their common connections to transnational university/academic partnerships. Our proposed matching solution is based on the integration of social science theories and specific artificial intelligence (AI) techniques. While the insights of social sciences, e.g., innovation studies and social network theory, have potential to answer the question of why TIC and TUC should be looked at as synergetic entities with elaborated conceptualization, the method of machine learning, as one specific technic off AI, can help answer the question of how to realize that synergy. On the way towards a transdisciplinary approach to TIC and TUC synergy building, or creating transnational university-industry co-innovation networks, the paper takes an initial step by examining what the supports and gaps of existing studies on the topic are, and using the context of EU-China science, technology and innovation cooperation as a testbed. This is followed by the introduction of our proposed approach and our suggestions for future research.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Automation and Systems Theory, Automation Technology and Mechanical Engineering
Contributors: Cai, Y., Ferrer, B. R., Lastra, J. L. M.
Publication date: 1 Sep 2019
Peer-reviewed: Yes

Publication information

Journal: Sustainability
Volume: 11
Issue number: 17
Article number: 4633
ISSN (Print): 2071-1050
Ratings: 
  • Scopus rating (2019): CiteScore 3.2 SJR 0.581 SNIP 1.165
Original language: English
ASJC Scopus subject areas: Geography, Planning and Development, Renewable Energy, Sustainability and the Environment, Management, Monitoring, Policy and Law
Keywords: Artificial intelligence, EU-China, Machine learning, Science, technology and innovation cooperation, Transdisciplinary approach, Transnational industry cooperation, Transnational innovation ecosystem, Transnational university cooperation
Electronic versions: 
Source: Scopus
Source ID: 85071972293

Research output: Contribution to journalArticleScientificpeer-review

The potential of biomethane in replacing fossil fuels in heavy transport-a case study on Finland

Electrification is a frequently discussed solution for reducing transport related carbon dioxide emissions. However, transport sectors such as aviation and heavy-duty vehicles remain dependent on on-board fuels. Here, biomethane is still a little exploited solution, and the case of heavy-duty vehicles is particularly underappreciated despite the recent technical advances and potentially notable emission reductions. This paper discusses the potential of biomethane in heavy-duty road transport in the case of Finland, where the utilization rate is low compared to the technical potential. To this end, the potential of biomethane production through both anaerobic digestion and gasification was calculated in three scenarios for the heavy-duty transport fleet, based on the literature values of biomethane potential and truck class fuel consumption. The authors find that approximately half of the heavy-duty transport in Finland could be biomethane fueled by 2030. The estimated production costs for biomethane (81-190 €/MWh) would be competitive with the current consumer diesel price (152 €/MWh). Utilizing the total biomethane potential in heavy-duty transport would furthermore decrease the respective carbon dioxide emissions by 50%. To accelerate the transition in the heavy-duty transport sector, a more comprehensive political framework is needed, taking into account both production and consumption.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Bio- and Circular Economy, Materials Science and Environmental Engineering, MAB Powertec Oy, Tampere University
Contributors: Pääkkönen, A., Aro, K., Aalto, P., Konttinen, J., Kojo, M.
Publication date: 1 Sep 2019
Peer-reviewed: Yes

Publication information

Journal: Sustainability
Volume: 11
Issue number: 17
Article number: 4750
ISSN (Print): 2071-1050
Ratings: 
  • Scopus rating (2019): CiteScore 3.2 SJR 0.581 SNIP 1.165
Original language: English
ASJC Scopus subject areas: Geography, Planning and Development, Renewable Energy, Sustainability and the Environment, Management, Monitoring, Policy and Law
Keywords: Anaerobic digestion, Biomethane, Carbon emission reduction, Finland, Heavy-duty transport, Renewable transport fuels, Transition, Wood gasification
Electronic versions: 
Source: Scopus
Source ID: 85071977101

Research output: Contribution to journalArticleScientificpeer-review

Towards a circular economy by leveraging hazardous resources: A case study of Fortum HorsePower

The increasingly efficient use of scarce resources is a central theme in the gradual transition towards a circular economy. Hazardous materials represent a category of resources that is often difficult—and potentially risky—to transport, store, or neutralize. As a result, hazardous materials are rarely included in closed material loops. The present paper analyzes HorsePower, a business concept centered around an innovative way of utilizing horse manure. Horse manure is generated in millions of tons in horse-rich countries such as the UK, Germany, and France. It is a hazardous resource, as it may spread diseases, and cannot be disposed of or landfilled economically. The content analysis of 21 semi-structured interviews carried out with different business actors participating in the HorsePower business network reveals that the success of HorsePower stems from its ability to combine the complementary capabilities and material needs of a relatively complex network of business actors including stables, sawmills, logistical service providers, and heat and power plants. Each actor receives added value; the benefits from participation are greater than the sacrifices of participation. Furthermore, the findings show that certain types of hazardous resources, when combined with resources produced by another actor, may be burned efficiently and safely in specific power plants, reducing the need for other types of fuel. The observations imply that novel approaches for effectively sharing ideas and resource needs across organizational boundaries are needed to facilitate the development of additional innovative CE business concepts, leveraging both actor-specific capabilities and intra-actor resource dependencies.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Industrial Engineering and Management, Research group: Center for Research on Operations Projects and Services, Research group: Center for Research on Project and Service Business (CROPS), Lappeenranta University of Technology
Contributors: Tura, N., Ahola, T.
Number of pages: 9
Pages: 518-526
Publication date: 1 Sep 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of Cleaner Production
Volume: 230
ISSN (Print): 0959-6526
Ratings: 
  • Scopus rating (2019): CiteScore 10.9 SJR 1.886 SNIP 2.394
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Environmental Science(all), Strategy and Management, Industrial and Manufacturing Engineering
Keywords: Business models, Business networks, Circular economy, Hazardous resources, Value creation
Source: Scopus
Source ID: 85066124307

Research output: Contribution to journalArticleScientificpeer-review

Cost optimal energy performance renovation measures in a municipal service building in a cold climate

The energy saving potential of existing buildings is significant compared to new buildings in the EU region. To reduce significantly the CO2 emissions of buildings, energy efficiency of old buildings need to be improved. Aim of this study is to determine cost-optimal solutions for energy renovation and renewable energy production systems for an old existing service building. The example building of this study is a residence for elderly people, which was built in 1955 and located in Finland. This study was carried out by a dynamic building simulation tool IDA-ICE and multi objective optimization tool MOBO. The cost-optimal renovation concepts were determined from over 2.6 billion renovation measure combinations to minimize both target energy consumption and life-cycle costs over 20 years. The results show that air-to-water heat pump is more cost effective heating system for the studied building than district heating from the building owner point of view. Improving thermal insulation level of the external walls from the original level is not the most cost-effective option to improve the energy efficiency of the building. Instead of that, for example, installation of PV and solar thermal systems are recommended in all the cost-optimal solutions regardless of the target energy consumption level.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Civil Engineering, Aalto University, Finnish Environment Institute, Nanjing Tech University
Contributors: Jokisalo, J., Sankelo, P., Vinha, J., Sirén, K., Kosonen, R.
Publication date: 13 Aug 2019

Host publication information

Title of host publication: CLIMA 2019 Congress : Bucharest, Romania, May 26-29, 2019
Publisher: EDP Sciences

Publication series

Name: E3S Web of Conferences
Volume: 111
ISSN (Print): 2555-0403
ASJC Scopus subject areas: Environmental Science(all), Energy(all), Earth and Planetary Sciences(all)

Bibliographical note

jufoid=86108

Source: Scopus
Source ID: 85071852938

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Optimization of emission reducing energy retrofits in Finnish apartment buildings

This study examined the cost-optimality of energy renovation on Finnish apartment buildings of different ages, built according to different energy performance requirements. Multi-objective optimization was utilized to minimize both CO2 emissions and life cycle cost (LCC). IDA-ICE simulations were performed to obtain the hourly heating demand of the buildings. Four building age classes and three heating systems (district heating, exhaust air heat pump and ground-source heat pump) were separately optimized. With district heating, it was possible to reduce emissions by 11%, while also reducing LCC. With heat pumps cost-savings could be achieved while reducing emissions by over 49%. With maximal (not cost-effective) investments, emissions could be reduced by more than 70% in all examined cases. In all cases, the cheapest solutions included solar electricity and sewage heat recovery. In old buildings, window upgrades and additional roof insulation were cost-effective. In new buildings, demand-based ventilation was included in all optimal solutions.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Civil Engineering, Aalto University
Contributors: Hirvonen, J., Jokisalo, J., Heljo, J., Kosonen, R.
Publication date: 13 Aug 2019

Host publication information

Title of host publication: CLIMA 2019 Congress : Bucharest, Romania, May 26-29, 2019
Publisher: EDP Sciences
Article number: 03002

Publication series

Name: E3S Web of Conferences
Volume: 111
ISSN (Print): 2555-0403
ASJC Scopus subject areas: Environmental Science(all), Energy(all), Earth and Planetary Sciences(all)

Bibliographical note

jufoid=86108

Source: Scopus
Source ID: 85071843244

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Understanding tariff designs and consumer behaviour to employ electric vehicles for secondary purposes in the United Kingdom

Electric Vehicle (EV) uptake has increased rapidly in the recent years. The rate of EV use is likely to increase in the future as well. At this point, the topic of using EVs for secondary purposes other than mobility and transport is getting more popular. This paper outlines the importance of tariff designs and EV consumer behaviour in achieving the business models such as Vehicle-to-Grid (V2G) and Vehicle-to-Home (V2H). We took the United Kingdom (UK) as a case study country to demonstrate how crucial electricity tariffs and consumer behaviour are.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Industrial Engineering and Management, University of Cambridge
Contributors: Küfeoğlu, S., Melchiorre, D. A., Kotilainen, K.
Number of pages: 6
Pages: 1-6
Publication date: 1 Jul 2019
Peer-reviewed: Yes

Publication information

Journal: ELECTRICITY JOURNAL
Volume: 32
Issue number: 6
ISSN (Print): 1040-6190
Ratings: 
  • Scopus rating (2019): CiteScore 2.7 SJR 0.616 SNIP 0.825
Original language: English
ASJC Scopus subject areas: Business and International Management, Energy (miscellaneous), Management of Technology and Innovation, Law
Keywords: Electric vehicle, Tariff, V2G, V2H
Source: Scopus
Source ID: 85066131134

Research output: Contribution to journalArticleScientificpeer-review

Photovoltaic properties of low-bandgap (0.7–0.9 eV) lattice-matched GaInNAsSb solar junctions grown by molecular beam epitaxy on GaAs

We demonstrate single junction GaInNAsSb solar cells with high nitrogen content, i.e. in the range of 5–8%, and bandgap energies close to 0.7 eV grown by molecular beam epitaxy. A good crystalline quality is demonstrated for the entire range of N concentrations. An average external quantum efficiency of 0.45 is demonstrated for GaInNAsSb solar cell with 6.2% N exhibiting a bandgap of 0.78 eV (no antireflection coatings has been applied). The internal quantum efficiency for the cell is 0.65 at E g + 0.2 eV. The solar cells exhibited bandgap-voltage offsets between 0.55 V (for N = 5.3%) and 0.66 V (for N = 7.9%). When used in a six-junction solar cell architecture under AM1.5D illumination, the estimated short-circuit current density corresponding to the 0.78 eV cell is 8.2 mA/cm 2 . Furthermore, using the parameters obtained for the GaInNAsSb junction with 6.2% N, we have estimated that such six-junction solar cell architecture could realistically attain an efficiency of over 50% at 1000 suns concentration.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Research group: ORC, Research group: Nanophotonics, Microscopy Center
Contributors: Isoaho, R., Aho, A., Tukiainen, A., Aho, T., Raappana, M., Salminen, T., Reuna, J., Guina, M.
Number of pages: 6
Pages: 198-203
Publication date: 15 Jun 2019
Peer-reviewed: Yes

Publication information

Journal: Solar Energy Materials and Solar Cells
Volume: 195
ISSN (Print): 0927-0248
Ratings: 
  • Scopus rating (2019): CiteScore 11.6 SJR 1.827 SNIP 1.799
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Renewable Energy, Sustainability and the Environment, Surfaces, Coatings and Films
Keywords: Dilute nitrides, GaInNAsSb, Molecular beam epitaxy, Multijunction solar cells
Electronic versions: 
Source: Scopus
Source ID: 85062810786

Research output: Contribution to journalArticleScientificpeer-review

Impact of Different Concrete Types on Radio Propagation: Fundamentals and Practical RF Measurements

By the 1960's, European countries faced a massive housing shortage due to changes in social structure and migration from rural areas to towns. This led to a rapid growth of suburban areas in the 1960's and 1970's. Concrete, as a building material became popular as the prefabrication techniques of precast concrete structures developed rapidly during this era, and these trends continue even today. In the near future, the number of frequency bands used by mobile wireless communication systems will increase and, in general, the trend is towards higher frequencies. This paper presents the results of measurements in which the RF attenuations of several different concrete types were determined on the basis of the permittivity of the material samples. The frequency ranges used in the measurements were 4.5 to 19 GHz and 26 to 40 GHz. In particular, at higher frequencies, the attenuation of various concrete grades is very different, and the level of RF attenuation of the outer wall cannot be predicted without knowing the age of the building and the concrete quality used in the element.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Engineering, Tampere University, VTT Technical Research Centre of Finland
Contributors: Asp, A., Hentilä, T., Valkama, M., Pikkuvirta, J., Hujanen, A., Huhtinen, I.
Publication date: 1 Jun 2019

Host publication information

Title of host publication: 2019 4th International Conference on Smart and Sustainable Technologies, SpliTech 2019
Publisher: IEEE
Editors: Rodrigues, J. J., Solic, P., Perkovic, T., Vukojevic, K., Rodrigues, J. J., Patrono, L., Nizetic, S.
ISBN (Electronic): 9789532900910
ASJC Scopus subject areas: Artificial Intelligence, Computer Networks and Communications, Instrumentation, Energy Engineering and Power Technology, Renewable Energy, Sustainability and the Environment
Keywords: energy-efficient buildings, outdoor-To-indoor propagation, penetration loss, plastering net, Radiowave propagation, RF measurements

Bibliographical note

INT=ceng,"Pikkuvirta, Jussa"

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Pre-Grant Signaling for Energy-Efficient 5G and Beyond Mobile Devices: Method and Analysis

Due to the severely limited battery capacities, the energy efficiency of mobile devices plays an important role in their usability. In general, the cellular subsystem is one of the major contributors to the energy consumption of a mobile device, thus improving its energy efficiency is of paramount importance. In this paper, a new concept of pre-grant message together with associated control plane signaling is introduced, aiming to reduce the energy consumption of the cellular subsystem in the downlink, without notable increase in the buffering delay or latency. The proposed method is fully independent of the ordinary discontinuous reception (DRX) principle, which means that both methods can co-exist and act together to efficiently reduce the energy consumption of the user equipment. The performance of the proposed scheme in terms of the false alarm and misdetection rates are investigated and evaluated, in both additive white Gaussian noise and Rayleigh fading channels. The obtained numerical results show that the pre-grant message signaling can be decoded very reliably and can reduce the system power consumption, relative to an ordinary DRX-only reference system, by up to 70%, 68%, and 62% for FTP traffic, video streaming and VoIP, respectively, at the cost of negligible increase in the signaling overhead. The proposed method is also compared in terms of the energy consumption and energy efficiency against another state-of-the-art power-saving mechanism, namely the wake-up radio-based approach. The obtained results show that the pre-grant approach outperforms the wake-up-based system under broad range of traffic characteristics.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Engineering, Helsinki R and D Center, Huawei Technologies Oy (Finland). Co. Ltd.
Contributors: Rostami, S., Heiska, K., Puchko, O., Leppanen, K., Valkama, M.
Number of pages: 15
Pages: 418-432
Publication date: 1 Jun 2019
Peer-reviewed: Yes

Publication information

Journal: IEEE Transactions on Green Communications and Networking
Volume: 3
Issue number: 2
Article number: 8616818
ISSN (Print): 2473-2400
Ratings: 
  • Scopus rating (2019): CiteScore 5.5 SJR 1.18 SNIP 1.804
Original language: English
ASJC Scopus subject areas: Computer Networks and Communications, Renewable Energy, Sustainability and the Environment
Keywords: 5G, discontinuous reception, energy efficiency, microsleep, power saving, signaling, UE, wake-up scheme

Bibliographical note

EXT="Rostami, Soheil"

Source: Scopus
Source ID: 85066002345

Research output: Contribution to journalArticleScientificpeer-review

Artificial intelligence yesterday, today and tomorrow

Artificial Intelligence (AI) is one of the current emerging technologies. In the history of computing AI has been in the similar role earlier - almost every decade since the 1950s, when the programming language Lisp was invented and used to implement self-modifying applications. The second time that AI was described as one of the frontier technologies was in the 1970s, when Expert Systems (ES) were developed. A decade later AI was again at the forefront when the Japanese government initiated its research and development effort to develop an AI-based computer architecture called the Fifth Generation Computer System (FGCS). Currently in the 2010s, AI is again on the frontier in the form of (self-)learning systems manifesting in robot applications, smart hubs, intelligent data analytics, etc. What is the reason for the cyclic reincarnation of AI? This paper gives a brief description of the history of AI and also answers the question above. The current AI “cycle” has the capability to change the world in many ways. In the context of the CE conference, it is important to understand the changes it will cause in education, the skills expected in different professions, and in society at large.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Computing Sciences, Tallinn University of Technology, University of Lapland, Computer Science Institute
Contributors: Jaakkola, H., Henno, J., Mäkelä, J., Thalheim, B.
Number of pages: 8
Pages: 860-867
Publication date: 1 May 2019

Host publication information

Title of host publication: 2019 42nd International Convention on Information and Communication Technology, Electronics and Microelectronics, MIPRO 2019 - Proceedings
Publisher: IEEE
Editors: Skala, K., Car, Z., Pale, P., Huljenic, D., Janjic, M., Koricic, M., Sruk, V., Ribaric, S., Grbac, T. G., Butkovic, Z., Cicin-Sain, M., Skvorc, D., Mauher, M., Babic, S., Gros, S., Vrdoljak, B., Tijan, E.
ISBN (Electronic): 9789532330984
ASJC Scopus subject areas: Computer Networks and Communications, Hardware and Architecture, Information Systems, Energy Engineering and Power Technology, Electrical and Electronic Engineering, Electronic, Optical and Magnetic Materials
Keywords: Artificial Intelligence, Computer, Computer-supported decision-making, Deep learning, Education, Emerging technology, Expert Systems, Fifth Generation Computer, Frontier technology, Learning, Lisp, Prolog

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Intelligent data service for farmers

The agricultural sector in Finland has been lagging behind in digital development. Development has long been based on increasing production by investing in larger machines. Over the past decade, change has begun to take place in the direction of digitalization. One of the challenges is that different manufacturers are trying to get farmers' data on their own closed cloud services. In the worst case, farmers may lose an overall view of their farms and opportunities for deeper data analysis because their data is located in different services. The goals and previously studied challenges of the 'MIKÄ DATA' project are described in this research. This project will build an intelligent data service for farmers, which is based on the Oskari platform. In the 'Peltodata' service, farmers can see their own field data and many other data sources layer by layer. The project is focused on the study of machine learning techniques to develop harvest yield prediction and find out the correlation between many data sources. The 'Peltodata' service will be ready at the end of 2019.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Computing Sciences
Contributors: Linna, P., Narra, N., Grönman, J.
Number of pages: 4
Pages: 1072-1075
Publication date: 1 May 2019

Host publication information

Title of host publication: 2019 42nd International Convention on Information and Communication Technology, Electronics and Microelectronics, MIPRO 2019 - Proceedings
Publisher: IEEE
Editors: Skala, K., Car, Z., Pale, P., Huljenic, D., Janjic, M., Koricic, M., Sruk, V., Ribaric, S., Grbac, T. G., Butkovic, Z., Cicin-Sain, M., Skvorc, D., Mauher, M., Babic, S., Gros, S., Vrdoljak, B., Tijan, E.
ISBN (Electronic): 9789532330984
ASJC Scopus subject areas: Computer Networks and Communications, Hardware and Architecture, Information Systems, Energy Engineering and Power Technology, Electrical and Electronic Engineering, Electronic, Optical and Magnetic Materials
Keywords: Agriculture, Artificial intelligence, Platform

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Teaching for virtual work

Universities are still mainly preparing students for the world, where 'do something useful', i.e. 'do something with your hands' was the main principle and work was done during strictly regulated time. But world has changed and traditional areas of human activity (what also are the main target in University courses) are rapidly diminishing. More important have become virtual products - computer programs, mobile apps, social networks, new types of digital currencies, IOT (voice in your bathroom suggesting to buy the next model of Alexa), video games, interactive TV, virtual reality etc. Most of these new areas are not present in current curricula and there are problems with involving them in curricula - (working) students know (some aspects of) these areas better than many of university teachers, since corresponding knowledge is not yet present in textbooks - it is present only on Internet. The Internet strongly influences both what we teach and how we teach.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Computing Sciences, Tallinn University of Technology, University of Lapland
Contributors: Henno, J., Jaakkola, H., Mäkelä, J.
Number of pages: 9
Pages: 818-826
Publication date: 1 May 2019

Host publication information

Title of host publication: 2019 42nd International Convention on Information and Communication Technology, Electronics and Microelectronics, MIPRO 2019 - Proceedings
Publisher: IEEE
Editors: Skala, K., Car, Z., Pale, P., Huljenic, D., Janjic, M., Koricic, M., Sruk, V., Ribaric, S., Grbac, T. G., Butkovic, Z., Cicin-Sain, M., Skvorc, D., Mauher, M., Babic, S., Gros, S., Vrdoljak, B., Tijan, E.
ISBN (Electronic): 9789532330984
ASJC Scopus subject areas: Computer Networks and Communications, Hardware and Architecture, Information Systems, Energy Engineering and Power Technology, Electrical and Electronic Engineering, Electronic, Optical and Magnetic Materials

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

GIS-data related route optimization, hierarchical clustering, location optimization, and kernel density methods are useful for promoting distributed bioenergy plant planning in rural areas

Currently, geographic information system (GIS) models are popular for studying location-allocation-related questions concerning bioenergy plants. The aim of this study was to develop a model to investigate optimal locations for two different types of bioenergy plants, for farm and centralized biogas plants, and for wood terminals in rural areas based on minimizing transportation distances. The optimal locations of biogas plants were determined using location optimization tools in R software, and the optimal locations of wood terminals were determined using kernel density tools in ArcGIS. The present case study showed that the utilized GIS tools are useful for bioenergy-related decision-making to identify potential bioenergy areas and to optimize biomass transportation, and help to plan power plant sizing when candidate bioenergy plant locations have not been defined in advance. In the study area, it was possible to find logistically viable locations for 13 farm biogas plants (>100 kW) and for 8 centralized biogas plants (>300 kW) using a 10-km threshold for feedstock supply. In the case of wood terminals, the results identified the most intensive wood reserves near the highest road classes, and two potential locations were determined.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Bio- and Circular Economy, University of Jyvaskyla, Seinäjoki University of Applied Sciences
Contributors: Laasasenaho, K., Lensu, A., Lauhanen, R., Rintala, J.
Number of pages: 11
Pages: 47-57
Publication date: 1 Apr 2019
Peer-reviewed: Yes

Publication information

Journal: Sustainable Energy Technologies and Assessments
Volume: 32
ISSN (Print): 2213-1388
Ratings: 
  • Scopus rating (2019): CiteScore 5.4 SJR 1.165 SNIP 1.294
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology
Keywords: Biogas, Circular economy, Location-allocation, Network analysis, Wood terminal
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 85061098980

Research output: Contribution to journalArticleScientificpeer-review

Energy Detection-Based Spectrum Sensing over Fisher-Snedecor F Fading Channels

This paper investigates the performance of energy detection-based spectrum sensing over Fisher-Snedecor F fading channels. To this end, an analytical expression for the corre- sponding average detection probability is firstly derived and then this is extended to account for collaborative spectrum sensing. The complementary receiver operating characteristics (ROC) are analyzed for different conditions of the average signal-to- noise ratio (SNR), time-bandwidth product, multipath fading, shadowing and number of collaborating users. It is shown that the energy detection performance is strongly linked to the severity of the multipath fading and amount of shadowing, whereby even small variations in either of these physical phenomena significantly impact the detection probability. Also, the versatile modeling capability of the Fisher-Snedecor F distribution is veridfied in the context of energy detection based spectrum sensing as it provides considerably more accurate characterization than the conventional Rayleigh fading model. To confirm the validity of the analytical results presented in this paper, we compare them with the results of some simulations.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Research group: Wireless Communications and Positioning, Electrical Engineering, Queen's University, Belfast, Northern Ireland, Centre for Wireless Innovation, Khalifa University, Department of Chemistry and Bioengineering, University of Surrey, German Jordanian University, Aristotle University of Thessaloniki
Contributors: Yoo, S. K., Cotton, S. L., Sofotasios, P. C., Muhaidat, S., Badarneh, O. S., Karagiannidis, G. K.
Publication date: 20 Feb 2019

Host publication information

Title of host publication: 2018 IEEE Global Communications Conference
Publisher: IEEE
Article number: 8647778
ISBN (Electronic): 9781538647271
ASJC Scopus subject areas: Information Systems and Management, Renewable Energy, Sustainability and the Environment, Safety, Risk, Reliability and Quality, Signal Processing, Modelling and Simulation, Instrumentation, Computer Networks and Communications
Source: Scopus
Source ID: 85063500863

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Improved Session Continuity in 5G NR with Joint Use of Multi-Connectivity and Guard Bandwidth

The intermittent millimeter-wave radio links as a result of human-body blockage are an inherent feature of the 5G New Radio (NR) technology by 3GPP. To improve session continuity in these emerging systems, two mechanisms have recently been proposed, namely, multi-connectivity and guard bandwidth. The former allows to establish multiple spatially-diverse connections and switch between them dynamically, while the latter reserves a fraction of system bandwidth for sessions changing their state from non-blocked to blocked, which ensures that the ongoing sessions have priority over the new ones. In this paper, we assess the joint performance of these two schemes for the user- and system-centric metrics of interest. Our numerical results reveal that the multi-connectivity operation alone may not suffice to increase the ongoing session drop probability considerably. On the other hand, the use of guard bandwidth significantly improves session continuity by somewhat compromising new session drop probability and system resource utilization. Surprisingly, the 5G NR system implementing both these techniques inherits their drawbacks. However, complementing it with an initial AP selection procedure effectively alleviates these limitations by maximizing the system resource utilization, while still providing sufficient flexibility to enable the desired trade-off between new and ongoing session drop probabilities.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Engineering, Department of Chemistry and Bioengineering, Peoples’ Friendship University of Russia
Contributors: Kovalchukov, R., Moltchanov, D., Begishev, V., Samuylov, A., Andreev, S., Koucheryavy, Y., Samouylov, K.
Publication date: 20 Feb 2019

Host publication information

Title of host publication: 2018 IEEE Global Communications Conference, GLOBECOM 2018
Publisher: IEEE
ISBN (Electronic): 9781538647271
ASJC Scopus subject areas: Information Systems and Management, Renewable Energy, Sustainability and the Environment, Safety, Risk, Reliability and Quality, Signal Processing, Modelling and Simulation, Instrumentation, Computer Networks and Communications
Source: Scopus
Source ID: 85063532495

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

The potential of electric trucks – An international commodity-level analysis

Development of battery technology is making battery electric heavy duty trucks technically and commercially viable and several manufacturers have introduced battery electric trucks recently. However, the national and sectoral differences in freight transport operations affect the viability of electric trucks. The aim of this paper is to develop a methodology for estimating the potential of electric trucks and demonstrate the results in Switzerland and Finland. Commodity-level analysis of the continuous road freight survey data were carried out in both countries. As much as 71% of Swiss road freight transport tonne-kilometers may be electrified using battery electric trucks but Finland has very limited potential of 35%, due to the use of long and heavy truck-trailer combinations. Within both countries the electrification potential varies considerably between commodities, although in Finland more so than in Switzerland. Commodities which are constrained by payload volume rather than weight and are to large extent carried using medium duty or <26t rigid trucks trucks seem to provide high potential for electrification even with the current technology. Electric trucks increase the annual electricity consumption by only 1–3%, but truck charging is likely to have a large impact on local grids near logistics centres and rest stations along major roads. A spatial analysis by routing the trips reported in the datasets used in this study should be carried out. Future research should also include comparison between the alternate ways of electrifying road freight transport, i.e. batteries with charging, batteries with battery swapping and electrified road systems.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Transport Research Centre Verne, Civil Engineering, HCI e 486.1
Contributors: Liimatainen, H., van Vliet, O., Aplyn, D.
Number of pages: 11
Pages: 804-814
Publication date: 15 Feb 2019
Peer-reviewed: Yes
Early online date: 14 Dec 2018

Publication information

Journal: Applied Energy
Volume: 236
ISSN (Print): 0306-2619
Ratings: 
  • Scopus rating (2019): CiteScore 16.4 SJR 3.607 SNIP 2.865
Original language: English
ASJC Scopus subject areas: Building and Construction, Energy(all), Mechanical Engineering, Management, Monitoring, Policy and Law
Keywords: Charging infrastructure, Electric trucks, Logistics, Road freight transport
Electronic versions: 
Source: Scopus
Source ID: 85058374379

Research output: Contribution to journalArticleScientificpeer-review

Impedance-based interactions in grid-tied three-phase inverters in renewable energy applications

Impedance-ratio-based interaction analyses in terms of stability and performance of DC-DC converters is well established. Similar methods are applied to grid-connected three-phase converters as well, but the multivariable nature of the converters and the grid makes these analyses very complex. This paper surveys the state of the interaction analyses in the grid-connected three-phase converters, which are used in renewable-energy applications. The surveys show clearly that the impedance-ratio-based stability assessment are usually performed neglecting the cross-couplings between the impedance elements for reducing the complexity of the analyses. In addition, the interactions, which affect the transient performance, are not treated usually at all due to the missing of the corresponding analytic formulations. This paper introduces the missing formulations as well as explicitly showing that the cross-couplings of the impedance elements have to be taken into account for the stability assessment to be valid. In addition, this paper shows that the most accurate stability information can be obtained by means of the determinant related to the associated multivariable impedance ratio. The theoretical findings are also validated by extensive experimental measurements.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Electrical Engineering, Research group: Power electronics, Research area: Power engineering, Automation Technology and Mechanical Engineering, Research group: Automation and Systems Theory, Aalto University
Contributors: Suntio, T., Messo, T., Berg, M., Alenius, H., Reinikka, T., Luhtala, R., Zenger, K.
Publication date: 31 Jan 2019
Peer-reviewed: Yes

Publication information

Journal: Energies
Volume: 12
Issue number: 3
Article number: 464
ISSN (Print): 1996-1073
Ratings: 
  • Scopus rating (2019): CiteScore 3.8 SJR 0.635 SNIP 1.154
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Energy (miscellaneous), Control and Optimization, Electrical and Electronic Engineering
Keywords: Grid synchronization, Power electronics, Power grid, Source and load impedance, Stability, Transient dynamics
Source: Scopus
Source ID: 85060952873

Research output: Contribution to journalReview ArticleScientificpeer-review

Direct fixed-step maximum power point tracking algorithms with adaptive perturbation frequency

Owing to the good trade-off between implementation and performance, fixed-step direct maximum power point tracking techniques (e.g., perturb and observe and incremental conductance algorithms) have gained popularity over the years. In order to optimize their performance, perturbation frequency and perturbation step size are usually determined a priori. While the first mentioned design parameter is typically dictated by the worst-case settling time of the combined energy conversion system, the latter must be high enough to both differentiate the system response from that caused by irradiation variation and match the finite resolution of the analog-to-digital converter in case of digital implementation. Well-established design guidelines, however, aim to optimize steady-state algorithm performance while leaving transients nearly untreated. To improve transient behavior while keeping the steady-state operation unaltered, variable step direct maximum power point tracking algorithms based on adaptive perturbation step size were proposed. This paper proposes a concept of utilizing adaptive perturbation frequency rather than variable step size, based on recently revised guidelines for designing fixed-step direct maximum power point tracking techniques. Preliminary results demonstrate the superiority of the proposed method over adaptive perturbation step size operation during transients, without compromising the steady state performance.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Engineering, Research group: Power electronics, Ben-Gurion University of the Negev
Contributors: Amer, E., Kuperman, A., Suntio, T.
Publication date: 27 Jan 2019
Peer-reviewed: Yes

Publication information

Journal: Energies
Volume: 12
Issue number: 3
Article number: 399
ISSN (Print): 1996-1073
Ratings: 
  • Scopus rating (2019): CiteScore 3.8 SJR 0.635 SNIP 1.154
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Energy (miscellaneous), Control and Optimization, Electrical and Electronic Engineering
Keywords: Maximum power point tracking, Perturbation frequency, Photovoltaic generators, Step size
Electronic versions: 
Source: Scopus
Source ID: 85060911593

Research output: Contribution to journalArticleScientificpeer-review

The economics of renewable CaC2 and C2H2 production from biomass and CaO

This article presents the economics of a bio-based CaC2/C2H2 production concept plant. The aim of the research was to study if renewable CaC2/C2H2 production could be competitive in comparison with current technologies. The starting point was to integrate a wood char production unit into a combined heat and power (CHP) plant with a bubbling fluidized bed (BFB) boiler. The wood char was reacted with CaO in an electric arc furnace (EAF). The production costs of the CaC2 were determined based on the wood char production costs as well as the EAF electric power consumption. The results showed that the C2H2 yield (18%) is similar to the current fossil-based production. However, the production costs proved to be even higher than the current selling prices of CaC2 and C2H2. With the chosen basic feedstock (20 €/MWh) and electricity prices (45 €/MWh) the production costs of CaC2 were calculated to be 725 €/t and for C2H2 1805 €/t. The cost effectiveness of the concept plant was determined using the payback time method including the time value of money. The break even selling prices were 747–920 €/t for the CaC2 and 1940–3015 €/t for C2H2 depending on the desired payback time (4–30 years). The key factors in the production costs of CaC2 and C2H2 are the price of electricity and the electrical efficiency of the EAF. The results also showed that recycling the Ca at the site could save up to 48% in fresh Ca material costs.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Test Rig Finland, Inc.
Contributors: Pääkkönen, A., Tolvanen, H., Kokko, L.
Number of pages: 9
Pages: 40-48
Publication date: 1 Jan 2019
Peer-reviewed: Yes
Early online date: 10 Nov 2018

Publication information

Journal: Biomass and Bioenergy
Volume: 120
ISSN (Print): 0961-9534
Ratings: 
  • Scopus rating (2019): CiteScore 6.6 SJR 1.11 SNIP 1.415
Original language: English
ASJC Scopus subject areas: Forestry, Renewable Energy, Sustainability and the Environment, Agronomy and Crop Science, Waste Management and Disposal
Keywords: /C, H, Poly-generation, Renewable CaC, Renewable chemicals, Techno-economic evaluation
Source: Scopus
Source ID: 85056214971

Research output: Contribution to journalArticleScientificpeer-review

Why social sustainability counts: The impact of corporate social sustainability culture on financial success

Awareness is growing in European companies of the importance of managing all aspects of sustainability. However, the elusive social aspect of sustainability and its influence on successful business has been under-investigated in corporate culture literature so far. The aim of this paper is to examine whether a correlation can be found between corporate social sustainability culture (expressed as explicit “items” of corporate values and practices emphasizing employee and societal well-being) and the financial success of a company. This is examined through a multiple regression analysis of two contrasting European polls, examining items indicating corporate social sustainability culture, and financial outcomes. The empirical results show that four specific success-related social sustainability dimensions of corporate culture are predictors of a company being classified as financially successful. These are: Sustainability strategy and leadership; Mission, communication and learning; Social care and work life; and Loyalty and identification. The paper contributes to the understanding of how to manage corporate social sustainability culture whilst supporting companies’ financial performance, and provides evidence-grounded recommendations to business managers and stakeholders aiming to manage social sustainability proactively by undertaking cultural change and development initiatives.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Mechanical Engineering and Industrial Systems, Deep White GmbH, Chalmers University of Technology, Politecnico di Milano, Festo AG & Co. KG, Panepistimion Patron
Contributors: Schönborn, G., Berlin, C., Pinzone, M., Hanisch, C., Georgoulias, K., Lanz, M.
Number of pages: 10
Pages: 1-10
Publication date: 1 Jan 2019
Peer-reviewed: Yes

Publication information

Journal: Sustainable Production and Consumption
Volume: 17
ISSN (Print): 2352-5509
Ratings: 
  • Scopus rating (2019): CiteScore 5.1 SJR 0.973 SNIP 1.307
Original language: English
ASJC Scopus subject areas: Environmental Engineering, Environmental Chemistry, Renewable Energy, Sustainability and the Environment, Industrial and Manufacturing Engineering
Keywords: Corporate culture, Corporate sustainability, Financial performance, Social sustainability, Success factors, Sustainability
Source: Scopus
Source ID: 85053411172

Research output: Contribution to journalArticleScientificpeer-review

Charge carrier dynamics in tantalum oxide overlayered and tantalum doped hematite photoanodes

We employ atomic layer deposition to prepare 50 nm thick hematite photoanodes followed by passivating them with a 0.5 nm thick Ta 2 O 5 -overlayer and compare them with samples uniformly doped with the same amount of tantalum. We observe a three-fold improvement in photocurrent with the same onset voltage using Ta-overlayer hematite photoanodes, while electrochemical impedance spectroscopy under visible light irradiation shows a decreased amount of surface states under water splitting conditions. The Ta-doped samples have an even higher increase in photocurrent along with a 0.15 V cathodic shift in the onset voltage and decreased resistivity. However, the surface state capacitance for the Ta-doped sample is twice that of the reference photoanode, which implies a larger amount of surface hole accumulation. We further utilize transient absorption spectroscopy in the sub-millisecond to second timescale under operating conditions to show that electron trapping in both Ta 2 O 5 -passivated and Ta-doped samples is markedly reduced. Ultrafast transient absorption spectroscopy in the sub-picosecond to nanosecond timescale shows faster charge carrier dynamics and reduced recombination in the Ta-doped hematite photoanode resulting in the increased photoelectrochemical performance when compared with the Ta 2 O 5 -overlayer sample. Our results show that passivation does not affect the poor charge carrier dynamics intrinsic to hematite based photoanodes. The Ta-doping strategy results in more efficient electron extraction, solving the electron trapping issue and leading to increased performance over the surface passivation strategy.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Chemistry & Advanced Materials, Materials Science and Environmental Engineering, Physics, Research group: Surface Science
Contributors: Ruoko, T., Hiltunen, A., Iivonen, T., Ulkuniemi, R., Lahtonen, K., Ali-Löytty, H., Mizohata, K., Valden, M., Leskelä, M., Tkachenko, N. V.
Number of pages: 10
Pages: 3206-3215
Publication date: Jan 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of Materials Chemistry A
Volume: 7
Issue number: 7
ISSN (Print): 2050-7488
Ratings: 
  • Scopus rating (2019): CiteScore 17.1 SJR 3.432 SNIP 1.683
Original language: English
ASJC Scopus subject areas: Chemistry(all), Renewable Energy, Sustainability and the Environment, Materials Science(all)
Electronic versions: 

Bibliographical note

INT=phys,"Ulkuniemi, Riina"

Source: Scopus
Source ID: 85061474749

Research output: Contribution to journalArticleScientificpeer-review

Back Reflector with Diffractive Gratings for Light-Trapping in Thin-Film III-V Solar Cells

We report on the development of light-trapping architectures applied to thin-film solar cells. In particular, we focus on enhancing the absorption at 1-eV spectral range for dilute nitride and quantum dot materials and report on the influence of planar back reflectors on the photovoltaic properties. Moreover, we discuss the properties of polymer diffraction gratings with enhanced light-trapping capability pointing to advantageous properties of pyramidal gratings. In order to understand the suitability of these polymer grating architectures for space applications, we have performed an electron irradiation study (1 MeV) revealing the absence of reflectance changes up to doses of 1×10 15 e-/cm 2 .

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Physics, Research group: ORC, Politecnico di Torino
Contributors: Aho, T., Tukiainen, A., Elsehrawy, F., Ranta, S., Raappana, M., Aho, A., Isoaho, R., Cappelluti, F., Guina, M.
Number of pages: 4
Publication date: 2019

Host publication information

Title of host publication:  2019 European Space Power Conference (ESPC)
Publisher: IEEE
ISBN (Print): 978-1-7281-2127-7
ISBN (Electronic): 978-1-7281-2126-0
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Renewable Energy, Sustainability and the Environment
Keywords: Solar Cell, Semiconducting III-V Materials

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Bio-hydrogen Production from Sewage Sludge: Screening for Pretreatments and Semi-continuous Reactor Operation

Abstract: The high volumes of sewage sludge produced have raised interests for simultaneous treatment and clean energy production, e.g. in the form of hydrogen. Pretreatment of sewage sludge is required to enhance microbial degradation and in turn hydrogen yield from sewage sludge. The potential of five substrate pretreatments, individually and in combinations, to increase biohydrogen production from mixed primary and secondary sewage sludge at four incubation pH (5, 7, 9, and 11) was studied in batch assays. Alkali + ultrasonication pretreatment increased the hydrogen production almost seven times (0.35 mmol H2/g VS) compared to untreated sewage sludge at initial pH 11. In general, higher hydrogen yields and lower acetate concentrations were obtained under alkaline conditions (pH 9 and 11), being more favorable for protein degradation and not favorable for hydrogen consumption via homoacetogenesis. Subsequently, fermentation of alkali + ultrasonication pretreated sewage sludge in a semi-continuous stirred tank reactor (CSTR) produced a maximum hydrogen yield of 0.1 mmol H2/g VS, three times higher than the yield obtained from alkali pretreated sludge. The gas produced in the CSTRs contained a low concentration of CO2 (< 5%), and is thus easily upgradable to biohydrogen. Graphic Abstract: [Figure not available: see fulltext.].

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Water Pollution Research Department, National Research Centre, Indian Institute of Technology Hyderabad, Natl. University of Ireland, Galway, Ain Shams University
Contributors: El-Qelish, M., Chatterjee, P., Dessì, P., Kokko, M., El-Gohary, F., Abo-Aly, M., Rintala, J.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Waste and Biomass Valorization
ISSN (Print): 1877-2641
Ratings: 
  • Scopus rating (2019): CiteScore 3.6 SJR 0.569 SNIP 1.035
Original language: English
ASJC Scopus subject areas: Environmental Engineering, Renewable Energy, Sustainability and the Environment, Waste Management and Disposal
Keywords: Alkali treatment, Continuously stirred tank reactor (CSTR), Dark fermentation, Pretreatment, Sewage sludge, Ultrasonication
Source: Scopus
Source ID: 85069208392

Research output: Contribution to journalArticleScientificpeer-review

Combined experimental and theoretical study of acetylene semi-hydrogenation over Pd/Al2O3

The semi-hydrogenation of acetylene (C 2 H 2 + H 2 = C 2 H 4 , ΔH = −172 kJ mol −1 )is a well-studied reaction that is important for purification of ethylene, C 2 H 4 , feed used in polyethylene production. Pd-based catalysts are most commonly used to remove acetylene from ethylene feed prior to Ziegler–Natta polymerization because acetylene is a poison for Ziegler–Natta catalysts. New applications of the analogous catalytic processes, with similar requirements for the conversion and selectivity, are considered for the storage of H 2 within the context of the H 2 economy. Here, a combination of experimental and theoretical studies was employed to explore the performance of synthesized Pd nanoparticles and the feasibility of using computational modelling for predicting their catalytic properties. Specifically, a model 5%Pd/Al 2 O 3 nanocatalyst was successfully synthesized using high-throughput flame spray pyrolysis (FSP)method. As a catalyst for acetylene semi-hydrogenation, the material shows high conversion of 97%, a modest selectivity of 62%, and a turnover frequency of ethylene formation of 5 s −1 . The experimental data were further supported by computational modelling of catalytic properties. Results of microkinetic simulations, based on parameters obtained from DFT calculations, over a Pd 30 /Al 2 O 3 (100)model system were correlated with experiments. The insights from this direct comparison of theory and experiments provide indications for future improvements of the theoretical predictions and for novel types of materials with improved catalytic properties.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Materials and Molecular Modeling, Research area: Computational Physics, Physics, INL - International Iberian Nanotechnology, Universidade do Porto, Tethis S.p.A., Forschungszentrum Jülich (FZJ), Iowa State University, Ames Laboratory, Norwegian Univ. of Sci. and Technol.
Contributors: Gonçalves, L. P., Wang, J., Vinati, S., Barborini, E., Wei, X. K., Heggen, M., Franco, M., Sousa, J. P., Petrovykh, D. Y., Soares, O. S. G., Kovnir, K., Akola, J., Kolen'ko, Y. V.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: International Journal of Hydrogen Energy
ISSN (Print): 0360-3199
Ratings: 
  • Scopus rating (2019): CiteScore 8 SJR 1.141 SNIP 1.377
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Condensed Matter Physics, Energy Engineering and Power Technology
Keywords: DFT, Heterogeneous catalysis, Hydrogenation, Kinetics, Modelling, Nanoclusters
Source: Scopus
Source ID: 85065260706

Research output: Contribution to journalArticleScientificpeer-review

Cost-optimal energy performance measures in a new daycare building in cold climate

New municipal service buildings must be energy effective, and cost-optimality is one of the criteria for selecting the suitable energy performance improvement measures. A daycare building in a cold climate was studied by means of simulation-based, multi-objective optimisation. Using a genetic algorithm, both target energy use and life-cycle cost of the selected measures were minimised. It was found that extensive insulation of the building envelope is not a cost-optimal method to reduce the daycare building energy use. Improving energy efficiency of the ventilation system, utilising solar energy on-site and employing a light control strategy are preferable ways of improving the building energy performance. Ground-source heat pump is a more cost-optimal heating system for the daycare building than district heating. The cost-optimal sizing of the heat pump is small, only 28% of the required maximum heating power. Abbreviations: AHU: air handling unit; CAV: constant air volume; COMBI: comprehensive development of nearly zero-energy municipal service buildings; COP: coefficient of performance; DH: district heating; DHW: domestic hot water; EPBD: energy performance of buildings directive; EU: European Union; FINVAC: Finnish Association of HVAC Societies; GSHP: ground-source heat pump; HRU: heat recovery unit; IDA ICE: IDA Indoor Climate and Energy; LED: light-emitting diode; MOBO: multi-objective building optimisation tool; NSGA-II: Non-dominated Sorting Genetic Algorithm II; nZEB: nearly zero-energy building; PV: photovoltaic; TRY: test reference year; VAV: variable air volume; ZEB: zero-energy building

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Equa Simulation Finland Oy, Aalto University, Sweco Finland Oy
Contributors: Sankelo, P., Jokisalo, J., Nyman, J., Vinha, J., Sirén, K.
Number of pages: 19
Pages: 104-122
Publication date: 2019
Peer-reviewed: Yes
Early online date: 15 Mar 2018

Publication information

Journal: International Journal of Sustainable Energy
Volume: 38
Issue number: 2
ISSN (Print): 1478-6451
Ratings: 
  • Scopus rating (2019): CiteScore 3 SJR 0.427 SNIP 0.595
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Energy(all), Process Chemistry and Technology, Fluid Flow and Transfer Processes
Keywords: Building simulation, daycare building, life-cycle cost, multi-objective optimisation, simulation-based optimisation, target energy use
URLs: 
Source: Scopus
Source ID: 85043677926

Research output: Contribution to journalArticleScientificpeer-review

Effect of apartment building energy renovation on hourly power demand

Optimal energy renovations of apartment buildings in Finland have a great impact on annual energy demand. However, reduction of energy demand does not necessarily translate into similar changes in peak power demand. Four different types of apartment buildings, representing the Finnish apartment building stock, were examined after optimal energy retrofits to see the influence of retrofitting on hourly power demand. Switching from district heating to ground-source heat pumps reduced emissions significantly under current energy mix. However, the use of ground-source heat pumps increased hourly peak electricity demand by 46–153%, compared to district heated apartment buildings. The corresponding increase in electrical energy demand was 30–108% in the peak month of January. This could increase the use of high emission peak power plants and negate some of the emission benefits. Solar thermal collectors and heat recovery systems could reduce purchased heating energy to zero in summer. Solar electricity could reduce median power demand in summer, but had only a little effect on peak power demand. The reduction in peak power demand after energy retrofits was less than the reduction in energy demand.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Aalto University, Nanjing Tech University
Contributors: Hirvonen, J., Jokisalo, J., Heljo, J., Kosonen, R.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: International Journal of Sustainable Energy
ISSN (Print): 1478-6451
Ratings: 
  • Scopus rating (2019): CiteScore 3 SJR 0.427 SNIP 0.595
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Energy(all), Process Chemistry and Technology, Fluid Flow and Transfer Processes
Keywords: apartment building, district heating, energy performance, Energy retrofits, greenhouse gas emissions, power demand
Source: Scopus
Source ID: 85065643393

Research output: Contribution to journalArticleScientificpeer-review

Guest editorial joint special section on power conversion & control in photovoltaic power plants

General information

Publication status: Published
MoE publication type: B1 Article in a scientific magazine
Organisations: Electrical Engineering, Research group: Power electronics, University of Washington Seattle, University of New Brunswick, Crop and Soil Sciences, Cornell Univ., University of Memphis, Fraunhofer IWES, National Taiwan University, University of Texas at Arlington, University of Minnesota Twin Cities, Clemson University, Sandia National Laboratories, New Mexico, University of Wollongong, Technical University of Crete, University of Alberta, Computer Science Institute, University of Cambridge, Temple University, Universita degli Studi di Padova, Italy, Universitat Politécnica de Catalunya, Nanjing University of Aeronautics and Astronautics, Aalborg University, Huazhong University of Science and Technology, Ryerson University, Khalifa University, University of Technology Sydney
Contributors: Johnson, B., Chang, L., Afridi, K., Ali, M. H., Von Appen, J., Chen, Y. M., Davoudi, A., Dhople, S., Enslin, J. H., Flicker, J., Islam, M. R., Koutroulis, E., Kim, K. A., Li, Y., Liserre, M., Long, T., Lu, X., Mattavelli, P., Rodriguez, P., Ruan, X., Suntio, T., Wang, H., Xu, D., Xu, W., Yazdani, A., Zeineldin, H., Zhu, J.
Number of pages: 2
Pages: 159-160
Publication date: 2019
Peer-reviewed: No

Publication information

Journal: IEEE Transactions on Energy Conversion
Volume: 34
Issue number: 1
ISSN (Print): 0885-8969
Ratings: 
  • Scopus rating (2019): CiteScore 9.3 SJR 1.776 SNIP 1.965
Original language: English
ASJC Scopus subject areas: Energy Engineering and Power Technology, Electrical and Electronic Engineering
Source: Scopus
Source ID: 85062840015

Research output: Contribution to journalEditorialScientific

Identification of three-phase grid impedance in the presence of parallel converters

Grid impedance is an important parameter which affects the control performance of grid-connected power converters. Several methods already exist for optimizing the converter control system based on knowledge of grid impedance value. Grid impedance may change rapidly due to fault or disconnection of a transmission line. Therefore, online grid identification methods have been recently proposed to have up-to-date information about the grid impedance value. This is usually done by perturbing the converter output current and measuring the response in output voltage. However, any parallel converters connected to the same interface point will cause errors, since the measured current differs from the current that is flowing through the grid interface point. This paper points out challenges and errors in grid impedance identification, caused by parallel converters and their internal control functions, such as grid-voltage support. Experimental grid-impedance measurements are shown from the power hardware-in-the-loop setup developed at DNV-GL Flexible Power Grid Lab.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Automation Technology and Mechanical Engineering, Research group: Automation and Systems Theory, Research group: Power electronics, Electrical Engineering, Eindhoven University of Technology, DNV-GL
Contributors: Luhtala, R., Messo, T., Roinila, T., Alenius, H., Jong, E. D., Burstein, A., Fabian, A.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Energies
Volume: 12
Issue number: 14
Article number: 2674
ISSN (Print): 1996-1073
Ratings: 
  • Scopus rating (2019): CiteScore 3.8 SJR 0.635 SNIP 1.154
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Energy (miscellaneous), Control and Optimization, Electrical and Electronic Engineering
Keywords: DC–AC power converters, Grid impedance identification, Power hardware-in-the-loop
Electronic versions: 
Source: Scopus
Source ID: 85068784950

Research output: Contribution to journalArticleScientificpeer-review

Narrow Bandgap Dilute Nitride Materials for 6-junction Space Solar Cells

Narrow bandgap p-i-n dilute nitride GaInNAsSb junctions, for use as bottom cell in 6-junction solar cells, are reported. In particular, we demonstrate a high optical quality for GaInNAsSb junction with a bandgap ~0.78 eV, corresponding to a N content of 6.2%. Under AM0 illumination, such cell exhibits a photocurrent of 36.6 mA/cm2. By extracting the parameters of the experimental cell, we estimate the the AM0 efficiency of a 6-junction multijunction solar cell employing the GaInNAsSb junction, to attain a value of 33%. Further improvements are discussed towards achieving the full potential of the 6-junction design.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Physics, Research group: ORC, Research group: Nanophotonics
Contributors: Isoaho, R., Aho, A., Tukiainen, A., Aho, T., Raappana, M., Salminen, T., Reuna, J., Guina, M.
Number of pages: 3
Publication date: 2019

Host publication information

Title of host publication: 2019 European Space Power Conference (ESPC)
Publisher: IEEE
ISBN (Print): 978-1-7281-2127-7
ISBN (Electronic): 978-1-7281-2126-0
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Renewable Energy, Sustainability and the Environment
Keywords: Solar cell, dilute nitride semiconductors, III-V semiconductor

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Power electronics in renewable energy systems

General information

Publication status: Published
MoE publication type: B1 Article in a scientific magazine
Organisations: Electrical Engineering, Research group: Power electronics, Research area: Power engineering
Contributors: Suntio, T., Messo, T.
Publication date: 2019
Peer-reviewed: No

Publication information

Journal: Energies
Volume: 12
Issue number: 10
Article number: en12101852
ISSN (Print): 1996-1073
Ratings: 
  • Scopus rating (2019): CiteScore 3.8 SJR 0.635 SNIP 1.154
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Energy (miscellaneous), Control and Optimization, Electrical and Electronic Engineering
Electronic versions: 
Source: Scopus
Source ID: 85066827333

Research output: Contribution to journalEditorialScientific

Remote diagnostics application software for remote handling equipment

The ITER Remote Handling Control System (RHCS) controllers provide measurement and diagnostics data about the remote handling equipment and tools they control. This paper presents the Remote Diagnostics Application (RDA) software for the analysis and archiving of the RHCS diagnostics data. The RDA provides a basic set of diagnostics tools, including trends, spectra, histograms, scatter plots, cross-correlation plots, as well as archiving and retrieval of history data. The ITER RH operators can extend diagnostics capabilities for specific RH equipment needs by incorporating custom diagnostics functions. To facilitate customization, RDA implements an architecture with three nested levels: the RDA Framework, its Diagnostics Workbenches and their Diagnostics Primitives. The RDA Framework has a user interface that can load one or several special diagnostics cases implemented as custom Diagnostics Workbenches with custom or default Diagnostics Primitives, such as rules, analysis functions and filters. As a result, the RDA features a diagnostics framework to execute complex and dedicated diagnostics and prognostics for the RH experts to monitor performance data, to run diagnostics tests and rules on equipment systems and to analyse historical data. The RDA helps the RH operators reduce downtime of the Remote Handling systems by exposing failure conditions and maintenance needs.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Automation Technology and Mechanical Engineering, VTT Technical Research Centre of Finland, Fusion For Energy (F4E)
Contributors: Alanen, J., Ruiz Morales, E., Muhammad, A., Saarinen, H., Minkkinen, J.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Fusion Engineering and Design
ISSN (Print): 0920-3796
Ratings: 
  • Scopus rating (2019): CiteScore 2.7 SJR 0.558 SNIP 1.049
Original language: English
ASJC Scopus subject areas: Civil and Structural Engineering, Nuclear Energy and Engineering, Materials Science(all), Mechanical Engineering
Keywords: Control system, Diagnostics, Prognostics, Remote handling, Software

Bibliographical note

EXT="Saarinen, Hannu"

Source: Scopus
Source ID: 85060619368

Research output: Contribution to journalArticleScientificpeer-review

Sustainability of bioenergy in finland and globally – fact check

The sustainability of bioenergy has attracted recently a lot of debate and there has been critical arguments for and against the use of bioenergy. This presentation examines six international publications dealing with the use of bioenergy and collects systematically the allegations of bioenergy, as well as arguments for defending and restricting bioenergy use in the publications. Some of the most controversial arguments are analyzed more thoroughly and they are subjected to fact checking by comparing arguments with sources in scientific literature. At the same time, the preconditions, restrictions, and assumptions that can be used to modify the claims to favor desired arguments are identified. The study finds that there are several problems that can be criticized towards the arguments. Arguments can be justified, among others, by looking at the situation over different time periods or by emphasizing the maximization of short-term or long-term climate benefits. Different values can be selected from initial data, whereupon their own argument can be confirmed.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Materials Science and Environmental Engineering, Lappeenranta University of Technology, Tampere University
Contributors: Vakkilainen, E., Konttinen, J., Orasuo, V., Aalto, P.
Number of pages: 2
Pages: 1634-1635
Publication date: 2019

Host publication information

Title of host publication: 27th European Biomass Conference and Exhibition, EUBCE 2019
Publisher: ETA-Florence Renewable Energies

Publication series

Name: European Biomass Conference and Exhibition Proceedings
ISSN (Print): 2282-5819
ASJC Scopus subject areas: Agronomy and Crop Science, Forestry, Renewable Energy, Sustainability and the Environment, Waste Management and Disposal
Keywords: Bioenergy, Carbon neutrality, Carbon sinks, Climate change, Fact check, Forest Biomass, Sustainability

Bibliographical note

jufoid=71903

Source: Scopus
Source ID: 85071067879

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Technology valuation method for supporting knowledge management in technology decisions to gain sustainability

New technologies have major effects on the profitability of companies and the economic growth of society. If appropriate technologies can be routinely selected, then it is possible to achieve sustainability at a company level. Knowledge management (KM) can be used to support technology decision making and give an understanding of the potential of particular technologies in a specific business environment. In this study, the design research methodology (DRM) is used with three case studies in an industry environment to develop and evaluate a novel technology valuation method (TVM). The proposed six-step TVM focuses on the acquisition, modeling, and validation of product-related knowledge to support KM related to technology decisions. The contribution of this research is to use distinctions between product properties and behaviors with a disposition toward understanding the potential of technology. During the process, tacit knowledge is made visible and documented, which supports the reliability of technology decisions and enables companies to gain sustainability.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Automation Technology and Mechanical Engineering, Sandvik Mining and Construction Oyj
Contributors: Mämmelä, J., Juuti, T., Julkunen, P.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Sustainability (Switzerland)
Volume: 11
Issue number: 12
Article number: 3410
ISSN (Print): 2071-1050
Ratings: 
  • Scopus rating (2019): CiteScore 3.2 SJR 0.581 SNIP 1.165
Original language: English
ASJC Scopus subject areas: Geography, Planning and Development, Renewable Energy, Sustainability and the Environment, Management, Monitoring, Policy and Law
Keywords: Knowledge management, Manufacturing industry, Sustainability, Technology, Technology decision, Technology valuation
Electronic versions: 

Bibliographical note

EXT="Julkunen, Pasi"

Source: Scopus
Source ID: 85069775222

Research output: Contribution to journalArticleScientificpeer-review

Towards the EU emissions targets of 2050: optimal energy renovation measures of Finnish apartment buildings

Member countries of the European Union have released targets to reduce carbon dioxide emissions by 80% by the year 2050. Energy use in buildings is a major source of these emissions, which is why this study focused on the cost-optimal renovation of Finnish apartment buildings. Apartment buildings from four different construction years (pre-1976, 1976–2002, 2003–2009 and post-2010) were modelled, using three different heating systems: district heating, ground-source heat pump and exhaust air heat pump. Multi-objective optimisation was utilised to find the most cost-effective energy renovation measures. Most cost-effective renovation measures were ground-source heat pumps, demand-based ventilation and solar electricity. Additional thermal insulation of walls was usually too expensive. By performing only the cost-effective renovations, the emissions could be reduced by 80%, 82%, 69% and 68%, from the oldest to the newest buildings, respectively. This could be done with the initial investment cost of 296, 235, 115 and 104 €/m2, respectively.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Aalto University, Nanjing Tech University
Contributors: Hirvonen, J., Jokisalo, J., Heljo, J., Kosonen, R.
Publication date: 2019
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: International Journal of Sustainable Energy
Volume: 38
Issue number: 7
ISSN (Print): 1478-6451
Ratings: 
  • Scopus rating (2019): CiteScore 3 SJR 0.427 SNIP 0.595
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Energy(all), Process Chemistry and Technology, Fluid Flow and Transfer Processes
Keywords: apartment building, Cost-optimal renovation, energy performance, greenhouse gas emissions, multi-objective optimisation
Source: Scopus
Source ID: 85058681434

Research output: Contribution to journalArticleScientificpeer-review

How and why does willow biochar increase a clay soil water retention capacity?

Addition of biochar into a soil changes its water retention properties by modifying soil textural and structural properties. In addition, internal micrometer-scale porosity that is able to directly store readily plant available water affects soil water retention properties. This study shows how precise knowledge of the internal micrometer-scale pore size distribution of biochar can deepen the understanding of the biochar-water interactions in soils. The micrometer-scale porosity of willow biochar was quantitatively and qualitatively characterized using X-ray tomography, 3D image analysis and Helium ion microscopy. The effect of biochar application on clay soil water retention was studied by conventional water retention curve approach. The results indicate that the internal pores of biochar, with sizes of at 50 and 10 μm (equivalent pore diameter), increased soil porosity and the amount of readily plant available water. After biochar addition, changes in soil porosity were detected at pore size regimes 5–10 and 25 μm, i.e. biochar pore sizes multiplied by factor 0.5. The detected pore size distribution of biochar does not predict directly (1:1 compatibility) the changes observed in the soil moisture characteristics. It is likely that biochar chemistry and pore morphology affect biochar-water interactions via e.g. surface roughness and contact angle. In addition, biochar induced changes in soil structure and texture affected soil moisture characteristics. However, the approach presented is an attractive pathway to more generalized understanding on how and why biochar internal porosity affects soil moisture characteristics.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Computational Biophysics and Imaging Group, Natural Resources Institute Finland (Luke), Jyväskylän yliopisto
Contributors: Rasa, K., Heikkinen, J., Hannula, M., Arstila, K., Kulju, S., Hyväluoma, J.
Number of pages: 8
Pages: 346-353
Publication date: 1 Dec 2018
Peer-reviewed: Yes

Publication information

Journal: Biomass and Bioenergy
Volume: 119
ISSN (Print): 0961-9534
Ratings: 
  • Scopus rating (2018): CiteScore 6.5 SJR 1.072 SNIP 1.275
Original language: English
ASJC Scopus subject areas: Forestry, Renewable Energy, Sustainability and the Environment, Agronomy and Crop Science, Waste Management and Disposal
Keywords: 3D image analysis, Biochar, Helium ion microscopy, Plant available water, Soil water retention, X-ray tomography
Electronic versions: 

Bibliographical note

EXT="Kulju, Sampo"

Source: Scopus
Source ID: 85054557305

Research output: Contribution to journalArticleScientificpeer-review

Energiatehokkaan arkkitehtisuunnittelun ohjekortisto

General information

Publication status: Published
MoE publication type: D5 Text book, professional manual or guide or a dictionary
Organisations: Architecture, Research group: ASUTUT
Contributors: Moisio, M., Kaasalainen, T., Lehtinen, T., Hedman, M.
Number of pages: 142
Publication date: Dec 2018

Publication information

Publisher: Tampereen teknillinen yliopisto. Arkkitehtuurin laboratorio
ISBN (Print): 978-952-15-4284-8
ISBN (Electronic): 978-952-15-4285-5
Original language: Finnish

Publication series

Name: Tampereen teknillinen yliopisto. Arkkitehtuurin laboratorio. Asuntosuunnittelu. Julkaisu
Volume: 32
ISSN (Print): 2242-4598
ASJC Scopus subject areas: Architecture , Renewable Energy, Sustainability and the Environment
Keywords: Energy efficiency, Architectural design, Service buildings, Building simulation

Research output: Book/ReportBookProfessional

Peruskoulut ja energiatehokkuus: Tilallisista ja toiminnallisista suunnitteluperiaatteista

General information

Publication status: Published
MoE publication type: D5 Text book, professional manual or guide or a dictionary
Organisations: Architecture, Research group: ASUTUT
Contributors: Lehtinen, T., Papinsaari, A., Kaasalainen, T., Moisio, M., Hedman, M.
Number of pages: 86
Publication date: Dec 2018

Publication information

Publisher: Tampereen teknillinen yliopisto. Arkkitehtuurin laboratorio
ISBN (Electronic): 978-952-15-4287-9
Original language: Finnish

Publication series

Name: Tampereen teknillinen yliopisto. Arkkitehtuurin laboratorio. Asuntosuunnittelu. Julkaisu
Volume: 34
ISSN (Print): 2242-4598
ASJC Scopus subject areas: Architecture , Renewable Energy, Sustainability and the Environment
Keywords: Energy efficiency, Architectural design, School building, Service buildings

Research output: Book/ReportBookProfessional

Creating value in the circular economy: A structured multiple-case analysis of business models

The circular economy (CE) has gained traction as a pathway towards more sustainable economic growth. The main actions leading towards a CE have been identified as the 3R principles of reduce, reuse, and recycle. However, understanding is lacking regarding how the adoption of CE using the 3R principles generates value and revenue in a business context. Thus, this study structurally examines business models used by CE-driven firms utilizing the fundamental business model components of value proposition, value creation/delivery, and value capture. By developing a detailed framework of business model components, acknowledging the particular features of CE implementation, and conducting a multiple-case study combining the business model approach with the 3R principles, this study analyzes feasible CE business models from multiple industries in Europe, the US, and China. The following five research propositions are derived from the findings of the explorative case analysis: 1) the cost-efficiency of circular operations is the key proponent to successful CE business, 2) take-back services enable the acquisition of particular wastes as resources, but they need to be incentivized through reductions in customers’ total waste management costs, 3) circular business models require the focal firm to separately manage multiple positions in the value chain, 4) the take-back system for gaining value through CE can be implemented successfully in multiple ways, and 5) recycling is easier to implement than reducing or reusing due to a smaller impact on the business. These propositions contribute to the circular business model literature by showing how economic value is generated by CE initiatives and providing foundations for theory-testing future research. The propositions also provide guidance for policymakers and managers on supporting and implementing circular business.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Industrial and Information Management, Research group: Center for Innovation and Technology Research
Contributors: Ranta, V., Aarikka-Stenroos, L., Mäkinen, S. J.
Number of pages: 13
Pages: 988-1000
Publication date: 10 Nov 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of Cleaner Production
Volume: 201
ISSN (Print): 0959-6526
Ratings: 
  • Scopus rating (2018): CiteScore 8.7 SJR 1.62 SNIP 2.317
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Environmental Science(all), Strategy and Management, Industrial and Manufacturing Engineering
Keywords: 3R principles, Business model, Circular economy, Value capture, Value creation, Value proposition
Source: Scopus
Source ID: 85053080716

Research output: Contribution to journalArticleScientificpeer-review

Flux-Weakening Control for IPMSM Employing Model Order Reduction

The variation of magnetic parameters due to the magnetic saturation and cross coupling can affect the efficiency and the stability of the control system in electrical machines, especially at high-speed operation. This paper presents an approach independent of the magnetic model parameters to control synchronous motors at the flux-weakening region. In this approach, a model order reduction technique is applied to reduce the finite element model of a synchronous machine. The stator current components and the flux linkage components are the inputs and the outputs of the reduced model, respectively. The reduced model and its inversion are employed to calculate the current reference components from the reference torque. Field oriented control scheme is utilized to implement the overall control system. The proposed control system is validated by means of simulation and experiment on a 2.2 kW permanent magnet synchronous machine.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering, Aalto University, Tallinn University of Technology
Contributors: Far, M. F., Mustafa, B., Martin, F., Rasilo, P., Belahcen, A.
Number of pages: 7
Pages: 1510-1516
Publication date: 24 Oct 2018

Host publication information

Title of host publication: 2018 23rd International Conference on Electrical Machines, ICEM 2018
Publisher: IEEE
ISBN (Electronic): 9781538624777
ASJC Scopus subject areas: Energy Engineering and Power Technology, Electrical and Electronic Engineering, Mechanical Engineering
Keywords: Flux weakening, Interior permanent magnet synchronous motor, Model order reduction, Orthogonal interpolation method, Vector control
Source: Scopus
Source ID: 85057179831

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Model Order Reduction of Bearingless Reluctance Motor Including Eccentricity

Eccentricity in a bearingless motor may occur during different operating states of the machine. This rises challenges in designing robust control for the machine with a lumped parameter model, due to the cross coupling of the windings with respect to the eccentric position of the rotor, the saturation of the ferromagnetic material, and spatial complexity. The non-linearity of the ferromagnetic material and the spatial harmonics can be considered in a finite element model of the machine, although applying it in a real time system is unreasonable. We propose a novel method based on orthogonal interpolation to reduce the order of the 2D finite element model of a bearingless synchronous reluctance motor, suitable for implementation in a real-time system. The winding currents and the eccentricity are given as inputs to the reduced model and the nodal values of the magnetic vector potential is obtained as the output, wherefrom the flux linkages, torque, and forces can be computed easily.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering, Aalto University, Tallinn University of Technology
Contributors: Far, M. F., Mukherjee, V., Martin, F., Rasilo, P., Belahcen, A.
Number of pages: 7
Pages: 2243-2249
Publication date: 24 Oct 2018

Host publication information

Title of host publication: 2018 23rd International Conference on Electrical Machines, ICEM 2018
Publisher: IEEE
ISBN (Electronic): 9781538624777
ASJC Scopus subject areas: Energy Engineering and Power Technology, Electrical and Electronic Engineering, Mechanical Engineering
Keywords: Bearingless synchronous reluctance motor, Eccentricity, Finite element analysis, Model order reduction, Orthogonal interpolation method
Source: Scopus
Source ID: 85057162208

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

A comparative analysis of global datasets and initiatives for urban health and sustainability

Globally, urban populations are growing rapidly, and in most cases their demands for resources are beyond current limits of sustainability. Cities are therefore critical for achieving national and international sustainability objectives, such as greenhouse gas reduction. Improving sustainability may also provide opportunities for urban population health co-benefits by reducing unhealthy exposures and behaviours. However, there is currently sparse empirical evidence on the degree to which city characteristics are associated with variations in health-related exposures, behaviours and sustainability. This paper examines the feasibility of aggregating empirical data relating to sustainability and health for global cities. An initial scoping review of existing English-language datasets and networks is performed. Resulting datasets are analysed for data types, collection method, and the distribution of contributing cities across climates, population sizes, and wealth. The review indicates datasets are populated using inconsistent methodologies and metrics and have poor overlap of cities between them. Data and organisations tend to be biased towards larger and wealthier cities, and concentrated in Europe and North America. Therefore, despite vast amounts of available data, limitations of reliability, representativeness, and disparate sources mean researchers are faced with significant obstacles when aggregating data to analyse the sustainability and health of globally representative samples of cities.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: University College London, London School of Hygiene and Tropical Medicine, The Energy and Resources Institute India, Fiocruz Bahia
Contributors: Taylor, J., Haines, A., Milner, J., Davies, M., Wilkinson, P., Sehgal, M., Singh, K. N., Barreto, M., Vianna, N., Teles, C.
Publication date: 11 Oct 2018
Peer-reviewed: Yes

Publication information

Journal: Sustainability (Switzerland)
Volume: 10
Issue number: 10
Article number: 3636
ISSN (Print): 2071-1050
Ratings: 
  • Scopus rating (2018): CiteScore 2.8 SJR 0.549 SNIP 1.201
Original language: English
ASJC Scopus subject areas: Geography, Planning and Development, Renewable Energy, Sustainability and the Environment, Management, Monitoring, Policy and Law
Keywords: Data, Health, Organizations, Sustainability, Urban
Source: Scopus
Source ID: 85054722697

Research output: Contribution to journalArticleScientificpeer-review

Quantification of bio-anode capacitance in bioelectrochemical systems using Electrochemical Impedance Spectroscopy

Understanding the electrochemical properties of bio-anodes is essential to improve performance of bioelectrochemical systems. Electrochemical Impedance Spectroscopy (EIS) is often used to study these properties in detail. Analysis of the EIS response, however, is challenging due to the interfering effect of the large capacitance of typically used graphite and carbon-based electrodes. In this study, we used flat electrodes made of conductive Fluorine-doped Tin Oxide (FTO) as anode, and monitored bio-anode performance. We show that with this configuration, it is possible to accurately separate the distinct contributions to the electrical response of the bio-anodes: charge transfer, biofilm and diffusion resistances, and biofilm capacitance. We observed that the capacitance of the biofilm increased from 2 μF cm−2 to 450 μF cm−2 during biofilm growth, showing a relationship with current and total produced charge. These results suggest that biofilm capacitance is a measure for the amount of active biomass in bioelectrochemical systems. At the end of the experiment, the biofilm was harvested from the FTO electrode and an average yield of 0.55 g COD biomass/mol e was determined.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Wageningen University and Research Centre, Wetsus, Centre for Sustainable Water Technology, Universitat Jaume I
Contributors: Heijne, A. T., Liu, D., Sulonen, M., Sleutels, T., Fabregat-Santiago, F.
Number of pages: 6
Pages: 533-538
Publication date: 1 Oct 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of Power Sources
Volume: 400
ISSN (Print): 0378-7753
Ratings: 
  • Scopus rating (2018): CiteScore 13.8 SJR 1.947 SNIP 1.484
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Physical and Theoretical Chemistry, Electrical and Electronic Engineering
Keywords: BES, Bioanode, Biomass yield, Capacitance, Electrochemical Impedance Spectroscopy, MET, Microbial fuel cell
Electronic versions: 
Source: Scopus
Source ID: 85052096235

Research output: Contribution to journalArticleScientificpeer-review

Cloud Enhancement Phenomenon and its Effect on PV Generators

Due to the cloud enhancement (CE) phenomenon, global horizontal irradiance can exceed the clear sky irradiance value. Enhanced irradiance areas are formed when photons are scattering from the water droplets in clouds near the direct irradiance path. The CE is well-known as a phenomenon, but its effect on photovoltaic (PV) generators has not been thoroughly studied. Output power of a PV generator is almost directly proportional to the irradiance. Therefore, due to the CE phenomenon, output power of a PV generator can exceed the nominal power, which affects the requirements set to the inverter. We used irradiance measurement data of 440 days from an array of pyranometers to calculate the speeds and movement directions of cloud shadows to deduce the diameters of enhancement areas. During the CE events, the irradiance values were occasionally more than 150% of the expected clear sky irradiance value. We discovered that the diameters of these extreme irradiance areas are tens of meters and, therefore, they can have a full effect on residential or commercial scale PV systems. Utility scale PV generators are in practice affected more by less extreme CE events with larger diameters, since spatial smoothing by the large generator area decreases the effects of the extreme events.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering
Contributors: Järvelä, M., Lappalainen, K., Valkealahti, S.
Pages: 1964-1968
Publication date: 25 Sep 2018

Host publication information

Title of host publication: 35th European Photovoltaic Solar Energy Conference and Exhibition (35th EU PVSEC), 24–28 September, 2018, Brussels, Belgium
ISBN (Electronic): 3-936338-50-7
ASJC Scopus subject areas: Energy(all)

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Automatic Meter Infrastructure (AMI) as a part of flexibility market

This paper gives an overview, how Automatic Meter Infrastructure (AMI) enable possibilities to participate flexibility markets. Paper introduces the current situation in Finnish electricity market and role of AMI for demand response. Flexibility market places available today in Finland are introduced with their technical specifications. Possibilities and development needs in AMI in respect to these requirements are discussed. These aspects need to be evaluated when planning new AMI projects. The paper proposes a novel AMI solution and business model based on requirements of flexibility market to realize large-scale demand response of small distributed energy resources. AMI-based demand response could be one of the solutions to activate customers and seems to be an interesting option to bring small scale resources in the flexibility market in cost-efficient manner.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering, Research group: Power systems, Research area: Power engineering, Elenia Oy
Contributors: Repo, S., Pylvänäinen, J., Kauppinen, M., Repo, S., Jarventausta, P.
Number of pages: 5
Publication date: 20 Sep 2018

Host publication information

Title of host publication: 15th International Conference on the European Energy Market, EEM 2018
Volume: 2018-June
Publisher: IEEE COMPUTER SOCIETY PRESS
Article number: 8469765
ISBN (Electronic): 9781538614884

Publication series

Name: International Conference on the European Energy Market
ISSN (Electronic): 2165-4093
ASJC Scopus subject areas: Marketing, Energy Engineering and Power Technology, Fuel Technology
Keywords: Demand-side management, Power distribution, Power system management, Smart grids

Bibliographical note

EXT="Repo, Sirpa"
EXT="Kauppinen, Markku"
jufoid=70631

Source: Scopus
Source ID: 85055486329

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Comparison of innovation policies for electric vehicle business ecosystems

Shift away from fossil fuel-based transportation is challenging countries to develop strategies for electric vehicle deployment. The transition offers countries also strategic opportunities in growing markets. Policy incentives are commonly used to help sustainability enhancing technologies to succeed in their journey from labs to markets. Electric vehicles are not standalone but require an ecosystem of related products, services and infrastructure and cannot be considered only from the transportation sector point of view. This paper compares electric vehicle innovation policies in four Nordic countries. The results show how different positions in the electric vehicle ecosystem these countries have chosen and how their choices reflect their economies.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Industrial and Information Management, Electrical Energy Engineering, Research group: Power systems, Research area: Power engineering, University of Tampere
Contributors: Valta, J., Makinen, S., Kotilainen, K., Rautiainen, A., Järventausta, P.
Number of pages: 5
Publication date: 20 Sep 2018

Host publication information

Title of host publication: 15th International Conference on the European Energy Market, EEM 2018
Volume: 2018-June
Publisher: IEEE COMPUTER SOCIETY PRESS
Article number: 8469785
ISBN (Electronic): 9781538614884

Publication series

Name: International Conference on the European Energy Market
ISSN (Electronic): 2165-4093
ASJC Scopus subject areas: Marketing, Energy Engineering and Power Technology, Fuel Technology
Keywords: Business ecosystems, Electric vehicle, Innovation policy

Bibliographical note

EXT="Kotilainen, Kirsi"

Source: Scopus
Source ID: 85055507417

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Effects of electric vehicles and heat pumps on long-term electricity consumption scenarios for rural areas in the nordic environment

Electrical energy consumption is undergoing major changes driven by several factors. Trends in electric vehicle (EV) purchases and heating system conversion indicate that changes in electricity demand can be significant between today and year 2030. For instance in Finland, the target for EVs is 250 000 passenger cars by 2030. At the same time, a significant number of heat pumps (HPs) will be installed in detached houses replacing old heating systems such as oil-fired boilers. In this paper, the effects of EVs and HPs on electricity consumption in Finnish rural areas are modeled and analyzed.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering, Research group: Power systems, Research area: Power engineering, Lappeenranta University of Technology, University of Eastern Finland
Contributors: Haakana, J., Haapaniemi, J., Lassila, J., Partanen, J., Niska, H., Rautiainen, A.
Number of pages: 5
Publication date: 20 Sep 2018

Host publication information

Title of host publication: 15th International Conference on the European Energy Market, EEM 2018
Volume: 2018-June
Publisher: IEEE COMPUTER SOCIETY PRESS
Article number: 8469937
ISBN (Electronic): 9781538614884

Publication series

Name: International Conference on the European Energy Market
ISSN (Electronic): 2165-4093
ASJC Scopus subject areas: Marketing, Energy Engineering and Power Technology, Fuel Technology
Keywords: Electric vehicles, Energy consumption, Heat pumps, Load modelling
Electronic versions: 
Source: Scopus
Source ID: 85055573281

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Microgrids as part of electrical energy system - Pricing scheme for network tariff of DSO

In the Smart Grid environment, one novel concept is the microgrid, which can be either a very small entity or a larger one. For example, the microgrid can consists of resources of an individual small customer or of several customers each with their own energy resources inside a low-voltage network. The microgrid can also consist of a large area with various energy resources and a connection to the distribution grid. Especially, when the number of these large-scale microgrids increases, a central question is what kind of network tariff structure should be applied to them. The network tariffs can affect whether the microgrids will have a connection to the distribution grid. In this paper, a novel tariff structure for a large-scale microgrid is proposed. The results show that the benefits of the microgrid can be shared more fairly between it and the distribution system by applying a novel network tariff.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering, Research group: Power systems, Research area: Power engineering, Lempäälän Energia Ltd., Laboratory of Electrical Energy Engineering
Contributors: Lummi, K., Rautiainen, A., Peltonen, L., Repo, S., Järventausta, P., Rintala, J.
Number of pages: 5
Publication date: 20 Sep 2018

Host publication information

Title of host publication: 15th International Conference on the European Energy Market, EEM 2018
Volume: 2018-June
Publisher: IEEE COMPUTER SOCIETY PRESS
Article number: 8469965
ISBN (Electronic): 9781538614884

Publication series

Name: International Conference on the European Energy Market
ISSN (Electronic): 2165-4093
ASJC Scopus subject areas: Marketing, Energy Engineering and Power Technology, Fuel Technology
Keywords: Distribution network tariff, Microgrid, Regulation
Source: Scopus
Source ID: 85055564419

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Use case description of real-time control of microgrid flexibility

Increasing amount of distributed energy resources necessitates more flexibility a t t he distribution network level. One option to attain this flexibility i s b y aggregation o f these resources within microgrids and further supervisory control of the latter in active network management. Among other reasons preventing their realization, these flexibility services I ack standardized information and communication technology solution. This study assesses the required communication, information, and functional competences for such services and describes them by means of a use case modeling on smart grid architecture model planes. Specifically, t he paper focuses o nan information exchange built on the basis of web application programming interface called Smart API. The results of the study present a smart grid architecture that would enable real-time control of microgrid resources in active network management through flexibility market services.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering, Research group: Power systems, Research area: Power engineering, Lappeenranta University of Technology, VTT Technical Research Centre of Finland
Contributors: Mashlakov, A., Tikka, V., Honkapuro, S., Partanen, J., Repo, S., Järventausta, P., Kulmala, A., Abdurafikov, R., Keski-Koukkari, A., Aro, M.
Number of pages: 5
Publication date: 20 Sep 2018

Host publication information

Title of host publication: 15th International Conference on the European Energy Market, EEM 2018
Volume: 2018-June
Publisher: IEEE COMPUTER SOCIETY PRESS
Article number: 8469218
ISBN (Electronic): 9781538614884

Publication series

Name: International Conference on the European Energy Market
ISSN (Electronic): 2165-4093
ASJC Scopus subject areas: Marketing, Energy Engineering and Power Technology, Fuel Technology
Keywords: Flexibility services, Information exchange interface, Microgrid flexibility, Real-time control, Smart grid architecture

Bibliographical note

EXT="Kulmala, Anna"
jufoid=70631

Source: Scopus
Source ID: 85055476487

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Alternative Power-Based Pricing Schemes for Distribution Network Tariff of Small Customers

The development of electricity distribution pricing is becoming an increasingly relevant topic due to various factors. The Distribution System Operators (DSO) face challenges regarding their tariffs of small customers when the customers invest in energy efficiency and small-scale energy production. Thus, the DSOs must evaluate their pricing practices to maintain a profitable and sustainable business. To respond to changes in the operational environment, transitioning toward power-based pricing is seen as a potential development direction. In this paper, we study various power-based distribution tariff (PBDT) structures and evaluate them from different viewpoints. To support the analysis, we provide a study where alternative tariff structures are analyzed based on data from two Finnish DSOs to investigate the impacts of the tariffs on the distribution fees of the customers and on the turnover of the DSO.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering, Helen Electricity Network Ltd., Elenia Ltd., Helen Electricity Network Ltd.
Contributors: Lummi, K., Rautiainen, A., Jarventausta, P., Heine, P., Lehtinen, J., Hyvarinen, M., Salo, J.
Number of pages: 6
Pages: 581-586
Publication date: 18 Sep 2018

Host publication information

Title of host publication: International Conference on Innovative Smart Grid Technologies, ISGT Asia 2018
Publisher: Institute of Electrical and Electronics Engineers Inc.
ISBN (Electronic): 9781538642917
ASJC Scopus subject areas: Artificial Intelligence, Computer Networks and Communications, Energy Engineering and Power Technology, Renewable Energy, Sustainability and the Environment, Electrical and Electronic Engineering
Keywords: Demand response, Demand tariff, Distribution network business, Network tariff, Power-based pricing

Bibliographical note

EXT="Lehtinen, Jouni"

Source: Scopus
Source ID: 85055529338

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Constrained Long-Horizon Direct Model Predictive Control for Synchronous Reluctance Motor Drives

A finite control set model predictive control strategy for the control of the stator currents of a synchronous reluctance motor driven by a three-level neutral point clamped inverter is presented in this paper. The presented algorithm minimizes the stator current distortions while operating the drive system at switching frequencies of a few hundred Hertz. Moreover, the power electronic converter is protected by overcurrents and/or overvoltages owing to a hard constraint imposed on the stator currents. To efficiently solve the underlying integer nonlinear optimization problem a sphere decoding algorithm serves as optimizer. To this end, a numerical calculation of the unconstrained solution of the optimization problem is proposed, along with modifications in the algorithm proposed in [1] so as to meet the above-mentioned control objectives. Simulation results show the effectiveness of the proposed control algorithm.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering, Research group: Power electronics, Universita degli Studi di Padova, Italy, Technische Universitat Munchen
Contributors: Ortombina, L., Liegmann, E., Karamanakos, P., Tinazzi, F., Zigliotto, M., Kennel, R.
Number of pages: 8
Publication date: 10 Sep 2018

Host publication information

Title of host publication: 2018 IEEE 19th Workshop on Control and Modeling for Power Electronics, COMPEL 2018
Publisher: IEEE
Article number: 8460173
ISBN (Print): 9781538655412
ASJC Scopus subject areas: Modelling and Simulation, Energy Engineering and Power Technology, Electrical and Electronic Engineering, Control and Optimization

Bibliographical note

JUFOID=79370

Source: Scopus
Source ID: 85054503298

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Performance of a biotrickling filter for the anaerobic utilization of gas-phase methanol coupled to thiosulphate reduction and resource recovery through volatile fatty acids production

The anaerobic removal of continuously fed gas-phase methanol (2.5–30 g/m3.h) and the reduction of step-fed thiosulphate (1000 mg/L) was investigated in a biotrickling filter (BTF) operated for 123 d at an empty bed residence time (EBRT) of 4.6 and 2.3 min. The BTF performance during steady step-feed and special operational phases like intermittent liquid trickling in 6 and 24 h cycles and operation without pH regulation were evaluated. Performance of the BTF was not affected and nearly 100% removal of gas-phase methanol was achieved with an ECmax of 21 g/m3.h. Besides, >99% thiosulphate reduction was achieved, in all the phases of operation. The production of sulphate, H2S and volatile fatty acids (VFA) was monitored and a maximum of 2500 mg/L of acetate, 200 mg/L of propionate, 150 mg/L of isovalerate and 100 mg/L isobutyrate was produced.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education, Institute for Water Education
Contributors: Eregowda, T., Matanhike, L., Rene, E. R., Lens, P. N.
Number of pages: 10
Pages: 591-600
Publication date: 1 Sep 2018
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 263
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2018): CiteScore 11.1 SJR 2.157 SNIP 1.858
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Renewable Energy, Sustainability and the Environment, Waste Management and Disposal
Keywords: Anaerobic, Biotrickling filter (BTF), Gas-phase methanol, Steady and intermittent BTF operation, Thiosulphate reduction, Volatile fatty acid
Source: Scopus
Source ID: 85047081553

Research output: Contribution to journalArticleScientificpeer-review

A distributed automation architecture for distribution networks, from design to implementation

With the current increase of distributed generation in distribution networks, line congestions and PQ issues are expected to increase. The smart grid may effectively coordinate DER, only when supported by a comprehensive architecture for automation. In IDE4L project such architecture is designed based on monitoring, control and business use cases. The IDE4L instance of SGAM architecture is derived and explained in details. The automation actor are specified in terms of interfaces, database and functions. The division in these three layers boosted the implementation phase as dedicated interfaces, databases or application has been developed in a modular way and can be installed in different HW/SW. Some implementation instances are presented and the main output of the architecture is discussed with regards to some indexes as communication traffic and level of distribution of automation functions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Energy Engineering, Research area: Power engineering, RWTH Aachen University, Surface and Corrosion Science, Catalonia Institute for Energy Research IREC, S.p.A., VTT Technical Research Centre of Finland
Contributors: Angioni, A., Lu, S., Hooshyar, H., Cairo, I., Repo, S., Ponci, F., Della Giustina, D., Kulmala, A., Dedè, A., Monti, A., Del Rosario, G., Vanfretti, L., Garcia, C. C.
Pages: 3-13
Publication date: Sep 2018
Peer-reviewed: Yes
Early online date: 27 Apr 2017

Publication information

Journal: Sustainable Energy, Grids and Networks
Volume: 15
ISSN (Print): 2352-4677
Ratings: 
  • Scopus rating (2018): CiteScore 5.2 SJR 0.99 SNIP 1.138
Original language: English
ASJC Scopus subject areas: Control and Systems Engineering, Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Electrical and Electronic Engineering
Keywords: Architecture, Distribution system, Smart grid

Bibliographical note

EXT="Kulmala, Anna"

Source: Scopus
Source ID: 85020176163

Research output: Contribution to journalArticleScientificpeer-review

Dilute nitride triple junction solar cells for space applications: Progress towards highest AM0 efficiency

We report a detailed performance assessment of triple junction dilute nitride solar cells fabricated by a combined molecular beam epitaxy-metal organic chemical vapor deposition process and designed for space applications. The experimental sample exhibits an efficiency level of 30.8% under AM0 illumination. Analyses of the isotype single junction dilute nitride bottom cells reveal a band gap voltage offset of 0.49 V at one sun illumination and a value as low as 0.47 V for full spectrum excitation without filter layers. The analyses point out the limitation of the design in terms of current balancing. With optimized design, an efficiency of 32.1% is possible, revealing the maturity reached by dilute nitride technology in the quest for improving the efficiency of lattice-matched multijunction solar cells.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, Research group: ORC, CESI S.p.A.
Contributors: Aho, A., Isoaho, R., Tukiainen, A., Gori, G., Campesato, R., Guina, M.
Number of pages: 5
Pages: 740-744
Publication date: Sep 2018
Peer-reviewed: Yes
Early online date: Apr 2018

Publication information

Journal: Progress in Photovoltaics: Research and Applications
Volume: 26
Issue number: 19
ISSN (Print): 1062-7995
Ratings: 
  • Scopus rating (2018): CiteScore 16.5 SJR 1.942 SNIP 2.42
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Renewable Energy, Sustainability and the Environment, Condensed Matter Physics, Electrical and Electronic Engineering
Source: Scopus
Source ID: 85045098254

Research output: Contribution to journalArticleScientificpeer-review

Lessons learnt from real-time monitoring of the low voltage distribution network

Up to now, the evolution of the distribution network toward the smart grid model has been essentially focused on two non-intersecting areas: medium voltage network automation and smart metering. The former one is mainly focused on improving the quality of service, studying and deploying fault location, isolation and service restoration systems, while the latter has been addressed to improve the customer relationship management, promote the customer awareness and enable new smart home services. In most cases a deep investigation of the low voltage network has been left disregarded, even if it represents the asset bridging the medium voltage level up to final customers. This network segment is probably the most affected by regulatory actions promoting intermittent renewable generations, distributed storage, heat pumps and the growing diffusion of electric vehicles utilization. The paper describes a field demonstrator of the FP7 European project IDE4L, where an extensive analysis of the low voltage network has been performed by means of an innovative use of smart meters and the installation of sensors on the medium-to-low voltage substation.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Energy Engineering, Research area: Power engineering, Research group: Power systems
Contributors: Barbato, A., Dedè, A., Della Giustina, D., Massa, G., Angioni, A., Lipari, G., Ponci, F., Repo, S.
Pages: 76-85
Publication date: Sep 2018
Peer-reviewed: Yes

Publication information

Journal: Sustainable Energy, Grids and Networks
Volume: 15
ISSN (Print): 2352-4677
Ratings: 
  • Scopus rating (2018): CiteScore 5.2 SJR 0.99 SNIP 1.138
Original language: English
ASJC Scopus subject areas: Control and Systems Engineering, Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Electrical and Electronic Engineering
Keywords: Distributed measurement system, Low voltage network, Smart grid, Smart metering
Source: Scopus
Source ID: 85021196165

Research output: Contribution to journalArticleScientificpeer-review

Production of alkanes from CO2 by engineered bacteria

Background: Microbial biosynthesis of alkanes is considered a promising method for the sustainable production of drop-in fuels and chemicals. Carbon dioxide would be an ideal carbon source for these production systems, but efficient production of long carbon chains from CO2 is difficult to achieve in a single organism. A potential solution is to employ acetogenic bacteria for the reduction of CO2 to acetate, and engineer a second organism to convert the acetate into long-chain hydrocarbons. Results: In this study, we demonstrate alkane production from CO2 by a system combining the acetogen Acetobacterium woodii and a non-native alkane producer Acinetobacter baylyi ADP1 engineered for alkane production. Nine synthetic two-step alkane biosynthesis pathways consisting of different aldehyde- and alkane-producing enzymes were combinatorically constructed and expressed in A. baylyi. The aldehyde-producing enzymes studied were AAR from Synechococcus elongatus, Acr1 from A. baylyi, and a putative dehydrogenase from Nevskia ramosa. The alkane-producing enzymes were ADOs from S. elongatus and Nostoc punctiforme, and CER1 from Arabidopsis thaliana. The performance of the pathways was evaluated with a twin-layer biosensor, which allowed the monitoring of both the intermediate (fatty aldehyde), and end product (alkane) formation. The highest alkane production, as indicated by the biosensor, was achieved with a pathway consisting of AAR and ADO from S. elongatus. The performance of this pathway was further improved by balancing the relative expression levels of the enzymes to limit the accumulation of the intermediate fatty aldehyde. Finally, the acetogen A. woodii was used to produce acetate from CO2 and H2, and the acetate was used for alkane production by the engineered A. baylyi, thereby leading to the net production of long-chain alkanes from CO2. Conclusions: A modular system for the production of drop-in liquid fuels from CO2 was demonstrated. Among the studied synthetic pathways, the combination of ADO and AAR from S. elongatus was found to be the most efficient in heterologous alkane production in A. baylyi. Furthermore, limiting the accumulation of the fatty aldehyde intermediate was found to be beneficial for the alkane production. Nevertheless, the alkane productivity of the system remained low, representing a major challenge for future research.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Lehtinen, T., Virtanen, H., Santala, S., Santala, V.
Publication date: 21 Aug 2018
Peer-reviewed: Yes

Publication information

Journal: Biotechnology for Biofuels
Volume: 11
Article number: 228
ISSN (Print): 1754-6834
Ratings: 
  • Scopus rating (2018): CiteScore 8.4 SJR 1.762 SNIP 1.468
Original language: English
ASJC Scopus subject areas: Biotechnology, Applied Microbiology and Biotechnology, Renewable Energy, Sustainability and the Environment, Energy(all), Management, Monitoring, Policy and Law
Keywords: Acetate, Acetogen, Acinetobacter baylyi ADP1, Aldehyde, Alkane, Biofuel, Biosensor, Carbon dioxide, CO, Drop in

Bibliographical note

INT=keb,"Virtanen, Henri"

Source: Scopus
Source ID: 85052519319

Research output: Contribution to journalArticleScientificpeer-review

Energy consumption of Finnish schools and daycare centers and the correlation to regulatory building permit values

The national building codes set requirements for building energy efficiency in many countries. The purpose of this study was to improve understanding on the measured and calculated energy efficiency of Finnish schools and daycare centers. The study analyzed the energy consumption of 134 schools and 71 daycare centers and compared the regulatory building permit calculations to measured values for 18 case buildings. According to the results, the specific electricity consumption (kW h/(m2 a)) has increased in schools but not in daycare centers. The heating energy consumption was lower in schools, but this might be explained by that they had clearly larger gross floor area than daycare centers. When compared to the technical requirements in the building code, the actual heating energy consumption has decreased less than what the changes in the building code would suggest. The building energy consumption calculated for building permits with the monthly calculation method and standard use clearly underestimated the measured building energy consumption. The differences were larger in heating energy than in electricity consumption. In conclusion, different regulatory limit values should be considered for the two building types. The calculation methods and input data should be analyzed to ensure that they truly guide towards cost-optimal design choices.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Research group: Building Physics
Contributors: Ruusala, A., Laukkarinen, A., Vinha, J.
Number of pages: 13
Pages: 183-195
Publication date: 1 Aug 2018
Peer-reviewed: Yes

Publication information

Journal: Energy Policy
Volume: 119
ISSN (Print): 0301-4215
Ratings: 
  • Scopus rating (2018): CiteScore 7.2 SJR 1.988 SNIP 1.825
Original language: English
ASJC Scopus subject areas: Energy(all), Management, Monitoring, Policy and Law, Building and Construction, Energy (miscellaneous)
Keywords: Building permit, Daycare center, Measured building energy consumption, Monthly calculation method, School building, Standard use
Source: Scopus
Source ID: 85046336515

Research output: Contribution to journalArticleScientificpeer-review

Selenate removal in biofilm systems: Effect of nitrate and sulfate on selenium removal efficiency, biofilm structure and microbial community

BACKGROUND: Selenium (Se) discharged into natural waterbodies can accumulate over time and have negative impacts on the environment. Se-laden wastewater streams can be treated using biological processes. However, the presence of other electron acceptors in wastewater, such as nitrate (NO3 -) and sulfate (SO4 2-), can influence selenate (SeO4 2-) reduction and impact the efficiency of biological treatment systems. RESULTS: SeO4 2- removal by biofilms formed from an anaerobic sludge inoculum was investigated in the presence of NO3 - and SO4 2- using drip flow reactors operated continuously for 10days at pH7.0 and 30°C. The highest total Se (∼60%) and SeO4 2- (∼80%) removal efficiencies were observed when the artificial wastewater contained SO4 2-. A maximum amount of 68μmol Se cm-2 was recovered from the biofilm matrix in SO4 2-+SeO4 2- exposed biofilms and biofilm mass was 2.7-fold increased for biofilms grown in the presence of SO4 2-. When SeO4 2- was the only electron acceptor, biofilms were thin and compact. In the simultaneous presence of NO3 - or SO4 2-, biofilms were thicker (> 0.6mm), less compact and exhibited gas pockets. CONCLUSION: The presence of SO4 2- had a beneficial effect on biofilm growth and the SeO4 2- removal efficiency, while the presence of NO3 - did not have a significant effect on SeO4 2- removal by the biofilms.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education, Montana State University (MSU), Bhabha Atomic Research Centre, UPEM
Contributors: Tan, L. C., Espinosa-Ortiz, E. J., Nancharaiah, Y. V., van Hullebusch, E. D., Gerlach, R., Lens, P. N.
Pages: 2380-2389
Publication date: Aug 2018
Peer-reviewed: Yes
Early online date: 1 Jan 2018

Publication information

Journal: Journal of Chemical Technology and Biotechnology
Volume: 93
Issue number: 8
ISSN (Print): 0268-2575
Ratings: 
  • Scopus rating (2018): CiteScore 4.8 SJR 0.715 SNIP 0.891
Original language: English
ASJC Scopus subject areas: Biotechnology, Chemical Engineering(all), Renewable Energy, Sustainability and the Environment, Fuel Technology, Waste Management and Disposal, Pollution, Organic Chemistry, Inorganic Chemistry
Keywords: Biofilm, Biofilm characterization, Co-electron acceptors, Nitrate, Selenate, Selenium removal, Sulfate
Source: Scopus
Source ID: 85043713774

Research output: Contribution to journalArticleScientificpeer-review

Design aspects of all atomic layer deposited TiO2–Fe2O3 scaffold-absorber photoanodes for water splitting

Iron and titanium oxides have attracted substantial attention in photoelectrochemical water splitting applications. However, both materials suffer from intrinsic limitations that constrain the final device performance. In order to overcome the limitations of the two materials alone, their combination has been proposed as a solution to the problems. Here we report on the fabrication of an atomic layer deposited (ALD) Fe2O3 coating on porous ALD-TiO2. Our results show that successful implementation requires complete mixing of the TiO2 and Fe2O3 layers via annealing resulting in the formation of a photoactive iron titanium oxide on the surface. Moreover, we found that incomplete mixing leads to crystallization of Fe2O3 to hematite that is detrimental to the photoelectrochemical performance. IPCE and transient photocurrent measurements performed using UV and visible light excitation confirmed that the iron titanium oxide extends the photocurrent generation to the visible range. These measurements were complemented by transient absorption spectroscopy (TAS), which revealed a new band absent in pristine hematite or anatase TiO2 that we assign to charge transfer within the structure. Taken together, these results provide design guidelines to be considered when aiming to combine TiO2 and Fe2O3 for photoelectrochemical applications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Research group: Surface Science, Photonics, Materials Science, Research group: Plastics and Elastomer Technology
Contributors: Hiltunen, A., Ruoko, T., Iivonen, T., Lahtonen, K., Ali-Löytty, H., Sarlin, E., Valden, M., Leskelä, M., Tkachenko, N.
Pages: 2124-2130
Publication date: 31 Jul 2018
Peer-reviewed: Yes

Publication information

Journal: Sustainable Energy & Fuels
Volume: 2
Issue number: 9
ISSN (Print): 2398-4902
Ratings: 
  • Scopus rating (2018): CiteScore 3.1 SNIP 0.85
Original language: English
ASJC Scopus subject areas: Electrochemistry, Renewable Energy, Sustainability and the Environment, Surfaces, Coatings and Films
Keywords: Water splitting, Atomic layer deposition (ALD), Titanium dioxide, Hematite, Cellulose, Template

Research output: Contribution to journalArticleScientificpeer-review

Efficient method for the real-time contingency analysis of meshed HVDC power grids fed by VSC stations

An efficient method for the real-time contingency analysis of meshed high-voltage direct current (HVDC) power grids fed by voltage source converter (VSC) stations is introduced here. A linearised AC/DC grid model is initially determined considering the control strategies of the various VSC units. This lays the foundations for the determination of linear sensitivity factors with which the contingency analysis is carried out to evaluate the real-time N-1 criterion in AC/DC grids, as demanded by system control centres. Distribution and power-injection factors are subsequently derived for efficiently assessing the impact of AC/DC transmission line outages and load/generator disconnections on the HVDC grid. Conversion factors are also derived to estimate the impact of the loss of VSC stations on the AC/DC network, this being another inherent contribution of this work. The efficiency and validity of this timely approach, which finds practical applicability to the real-time operation of HVDC power grids, is confirmed using a meshed DC network fed by three VSC stations. The disconnection of AC and DC transmission lines, generators, and VSC stations are dynamically simulated using Simulink and their post-disturbance steady-state conditions are compared against those computed by the introduced method where it is confirmed that both solutions concur very well with each other.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Energy Engineering, Department of Electrical Engineering
Contributors: Castro, L. M., Acha, E., Rodriguez-Rodriguez, J. R.
Number of pages: 9
Pages: 3158-3166
Publication date: 31 Jul 2018
Peer-reviewed: Yes

Publication information

Journal: IET Generation, Transmission and Distribution
Volume: 12
Issue number: 13
ISSN (Print): 1751-8687
Ratings: 
  • Scopus rating (2018): CiteScore 5.3 SJR 1.099 SNIP 1.512
Original language: English
ASJC Scopus subject areas: Control and Systems Engineering, Energy Engineering and Power Technology, Electrical and Electronic Engineering
Source: Scopus
Source ID: 85050235242

Research output: Contribution to journalArticleScientificpeer-review

Mechanical stress analysis during a quench in CLIQ protected 16 T dipole magnets designed for the future circular collider

Protecting the magnets in case of a quench is a challenge for the 16 T superconducting dipole magnets presently designed for the 100 TeV: Future Circular Collider (FCC). These magnets are driven to the foreseen technological limits in terms of critical current, mechanical strength and quench protection. The magnets are protected with CLIQ (Coupling-Loss Induced Quench) system, which is a recently developed quench protection method based on discharging a capacitor bank across part of the winding. The oscillation of the magnet currents and the dissipation of the high stored energy into the windings cause electrodynamic forces and thermal stresses, which may need to be considered in the magnet mechanical design. This paper focuses on mechanical stress analysis during a quench of the 16 T cos-θ and block type dipole magnets. A finite element model allowed studying the stress due to the non-uniform temperature and current distribution in the superconducting coils. Two different CLIQ configurations were considered for the cos-θ design and one for the block type magnet. The analyses of the mechanical behavior of two magnets during a quench without or with hot spot turn were separately carried out. The simulation results show that the stress related to a quench should be considered when designing a high field magnet.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Energy Engineering, Research group: Modelling and superconductivity, Lanzhou University, European Organization for Nuclear Research, Laboratorio Accelatori e Superconduttività Applicata, French Atomic Energy Commission (CEA) Saclay, Università degli Studi di Milano
Contributors: Zhao, J., Prioli, M., Stenvall, A., Salmi, T., Gao, Y., Caiffi, B., Lorin, C., Marinozzi, V., Farinon, S., Sorbi, M.
Number of pages: 8
Pages: 27-34
Publication date: 15 Jul 2018
Peer-reviewed: Yes

Publication information

Journal: Physica C: Superconductivity and its Applications
Volume: 550
ISSN (Print): 0921-4534
Ratings: 
  • Scopus rating (2018): CiteScore 2.7 SJR 0.463 SNIP 0.922
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Condensed Matter Physics, Energy Engineering and Power Technology, Electrical and Electronic Engineering
Keywords: Accelerator magnet, CLIQ protection system, Finite element analysis, Lorentz forces, Quench, Thermal stress
Source: Scopus
Source ID: 85045717268

Research output: Contribution to journalArticleScientificpeer-review

Metabolic pairing of aerobic and anaerobic production in a one-pot batch cultivation

Background: The versatility of microbial metabolic pathways enables their utilization in vast number of applications. However, the electron and carbon recovery rates, essentially constrained by limitations of cell energetics, are often too low in terms of process feasibility. Cocultivation of divergent microbial species in a single process broadens the metabolic landscape, and thus, the possibilities for more complete carbon and energy utilization. Results: In this study, we integrated the metabolisms of two bacteria, an obligate anaerobe Clostridium butyricum and an obligate aerobe Acinetobacter baylyi ADP1. In the process, a glucose-negative mutant of A. baylyi ADP1 first deoxidized the culture allowing C. butyricum to grow and produce hydrogen from glucose. In the next phase, ADP1 produced long chain alkyl esters (wax esters) utilizing the by-products of C. butyricum, namely acetate and butyrate. The coculture produced 24.5 ± 0.8 mmol/l hydrogen (1.7 ± 0.1 mol/mol glucose) and 28 mg/l wax esters (10.8 mg/g glucose). Conclusions: The cocultivation of strictly anaerobic and aerobic bacteria allowed the production of both hydrogen gas and long-chain alkyl esters in a simple one-pot batch process. The study demonstrates the potential of 'metabolic pairing' using designed microbial consortia for more optimal electron and carbon recovery.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering
Contributors: Salmela, M., Lehtinen, T., Efimova, E., Santala, S., Mangayil, R.
Publication date: 3 Jul 2018
Peer-reviewed: Yes

Publication information

Journal: Biotechnology for Biofuels
Volume: 11
Issue number: 1
Article number: 187
ISSN (Print): 1754-6834
Ratings: 
  • Scopus rating (2018): CiteScore 8.4 SJR 1.762 SNIP 1.468
Original language: English
ASJC Scopus subject areas: Biotechnology, Applied Microbiology and Biotechnology, Renewable Energy, Sustainability and the Environment, Energy(all), Management, Monitoring, Policy and Law
Keywords: Hydrogen production, Integrated metabolism, Metabolic pairing, Synthetic microbial consortia, Wax esters
Electronic versions: 
Source: Scopus
Source ID: 85049884043

Research output: Contribution to journalArticleScientificpeer-review

Cross-impact analysis of Finnish electricity system with increased renewables: Long-run energy policy challenges in balancing supply and consumption

Climate change and global economic pressures are strong drivers for energy economies to transition towards climate-neutrality, low-carbon economy and better energy and resource efficiencies. The response to these pressures, namely the increased use of renewable energy, creates a set of new challenges related to supply-demand balance for energy policy and electricity system planning. This study analyses the emergent problems resulting from the renewable energy response. These complex aspects of change in the electricity system are analysed with a cross-impact model based on an expert-driven modeling process, consisting of workshops, panel evaluations and individual expert work. The model is then analysed using a novel computational cross-impact technique, EXIT. The objective of the study is to map the important direct drivers of change in the period 2017–2030 in electricity consumption and production in Finland, construct a cross-impact model from this basis, and discover the emergent and systemic dynamics of the modeled system by analysis of this model.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Energy Engineering, Automation and Hydraulic Engineering
Contributors: Panula-Ontto, J., Luukkanen, J., Kaivo-oja, J., O'Mahony, T., Vehmas, J., Valkealahti, S., Björkqvist, T., Korpela, T., Järventausta, P., Majanne, Y., Kojo, M., Aalto, P., Harsia, P., Kallioharju, K., Holttinen, H., Repo, S.
Number of pages: 10
Pages: 504-513
Publication date: 1 Jul 2018
Peer-reviewed: Yes

Publication information

Journal: Energy Policy
Volume: 118
ISSN (Print): 0301-4215
Ratings: 
  • Scopus rating (2018): CiteScore 7.2 SJR 1.988 SNIP 1.825
Original language: English
ASJC Scopus subject areas: Energy(all), Management, Monitoring, Policy and Law
Keywords: Cross-impact analysis, Electricity system, Low-carbon, Renewables, Transition
Electronic versions: 
Source: Scopus
Source ID: 85045762685

Research output: Contribution to journalArticleScientificpeer-review

Improved modelling of electric loads for enabling demand response by applying physical and data-driven models: Project Response

Accurate load and response forecasts are a critical enabler for high demand response penetrations and optimization of responses and market actions. Project RESPONSE studies and develops methods to improve the forecasts. Its objectives are to improve 1) load and response forecast and optimization models based on both data-driven and physical modelling, and their hybrid models, 2) utilization of various data sources such as smart metering data, weather data, measurements from substations etc., and 3) performance criteria of load forecasting. The project applies, develops, compares, and integrates various modelling approaches including partly physical models, machine learning, modern load profiling, autoregressive models, and Kalman-filtering. It also applies non-linear constrained optimization to load responses. This paper gives an overview of the project and the results achieved so far.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering, Research group: Power systems, Research area: Information Systems in Automation, Automation and Hydraulic Engineering, VTT Technical Research Centre of Finland, University of Eastern Finland
Contributors: Koponen, P., Hanninen, S., Mutanen, A., Koskela, J., Rautiainen, A., Järventausta, P., Niska, H., Kolehmainen, M., Koivisto, H.
Number of pages: 6
Pages: 1-6
Publication date: 27 Jun 2018

Host publication information

Title of host publication: 2018 IEEE International Energy Conference, ENERGYCON 2018
Publisher: IEEE
ISBN (Electronic): 9781538636695
ASJC Scopus subject areas: Artificial Intelligence, Energy Engineering and Power Technology, Control and Optimization
Keywords: Active demand, Forecasting, Hybrid models, Machine learning, Optimization, Physically based models
Electronic versions: 
Source: Scopus
Source ID: 85050244199

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Online dynamic conductance estimation based maximum power point tracking of photovoltaic generators

In this paper, a novel method of maximum power point tracking of renewable energy generators is proposed, utilizing the sum of dynamic and static conductance as maximum power point tracking loop variable. This allows to formulate the maximum power point tracking problem as a typical closed-loop stabilization task of non-linear static plant with zero reference. Consequently, a simple integrative controller is shown to be sufficient to ensure zero steady-state maximum power point tracking error with easily determinable nominal dynamics. A recently revealed method of online photovoltaic generator dynamic conductance estimation allowing robust terminal voltage control is utilized. Moreover, it is revealed that the resulting maximum power point tracking loop plant is piecewise linear around the maximum power point, i.e. for given environmental conditions two different convergence rates are expected, depending on the relative value of operating voltage to maximum power point voltage. Presented analytical outcomes are verified by application of the proposed maximum power point tracking structure to a grid-connected photovoltaic generator system under robust voltage control.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Energy Engineering, Ariel University Center of Samaria, Ben-Gurion University of the Negev
Contributors: Sitbon, M., Lineykin, S., Schacham, S., Suntio, T., Kuperman, A.
Number of pages: 10
Pages: 687-696
Publication date: 15 Jun 2018
Peer-reviewed: Yes

Publication information

Journal: Energy Conversion and Management
Volume: 166
ISSN (Print): 0196-8904
Ratings: 
  • Scopus rating (2018): CiteScore 12.4 SJR 2.73 SNIP 2.181
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Nuclear Energy and Engineering, Fuel Technology, Energy Engineering and Power Technology
Keywords: Dynamic conductance, Maximum power point tracking, Renewable energy generators
Source: Scopus
Source ID: 85046490026

Research output: Contribution to journalArticleScientificpeer-review

Sustainable electric vehicle - Prosumer framework and policy mix

Electric vehicles have pro-environmental advantages compared to traditional automobiles, or even hybrids: they can help reducing pollution and noise levels locally, and greenhouse gas emissions globally. However, there are still many challenges that the electric vehicles must overcome before reaching level of diffusion that can have significant impact on sustainability. This paper evaluates combined sustainability of electric vehicle and small-scale energy production. We propose a framework for sustainable electric vehicle - energy prosumer integration and outline a policy mix that is needed to support adoption of both renewable energy technologies and electric vehicles.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Industrial and Information Management, School of Management Politics
Contributors: Kotilainen, K., Mäkinen, S. J., Valta, J.
Number of pages: 6
Pages: 1-6
Publication date: 8 Jun 2018

Host publication information

Title of host publication: 2017 IEEE Innovative Smart Grid Technologies - Asia : Smart Grid for Smart Community, ISGT-Asia 2017
Publisher: IEEE
ISBN (Electronic): 9781538649503
ASJC Scopus subject areas: Artificial Intelligence, Computer Networks and Communications, Energy Engineering and Power Technology, Electrical and Electronic Engineering, Control and Optimization, Safety, Risk, Reliability and Quality
Keywords: Electric vehicle, Policy, Prosumer, Renewable energy, Sustainable

Bibliographical note

EXT="Kotilainen, Kirsi"

Source: Scopus
Source ID: 85050005345

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Effects of wastewater constituents and operational conditions on the composition and dynamics of anodic microbial communities in bioelectrochemical systems

Over the last decade, there has been an ever-growing interest in bioelectrochemical systems (BES) as a sustainable technology enabling simultaneous wastewater treatment and biological production of, e.g. electricity, hydrogen, and further commodities. A key component of any BES degrading organic matter is the anode where electric current is biologically generated from the oxidation of organic compounds. The performance of BES depends on the interactions of the anodic microbial communities. To optimize the operational parameters and process design of BES a better comprehension of the microbial community dynamics and interactions at the anode is required. This paper reviews the abundance of different microorganisms in anodic biofilms and discusses their roles and possible side reactions with respect to their implications on the performance of BES utilizing wastewaters. The most important operational parameters affecting anodic microbial communities grown with wastewaters are highlighted and guidelines for controlling the composition of microbial communities are given.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Chemistry and Bioengineering, Laboratory for MEMS Applications, Universitat Freiburg im Breisgau, Karlsruhe Institute of Technology, Insitute for Technical Physics, Germany, University of Bremen
Contributors: Kokko, M., Epple, S., Gescher, J., Kerzenmacher, S.
Number of pages: 14
Pages: 376-389
Publication date: 1 Jun 2018
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 258
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2018): CiteScore 11.1 SJR 2.157 SNIP 1.858
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Renewable Energy, Sustainability and the Environment, Waste Management and Disposal
Keywords: Bioelectrochemical system, Exoelectrogen, Microbial community, Wastewater
Source: Scopus
Source ID: 85043472557

Research output: Contribution to journalReview ArticleScientificpeer-review

Role of Oxide Defects in ALD grown TiO2 Coatings on Performance as Photoanode Protection Layer

Photoelectrochemical (PEC) water splitting is one of the potential methods of utilizing solar energy. A major issue for the method and for renewable energy production is the development of an efficient, chemically stable and cost-effective semiconductor photoanode. Recently, titanium dioxide (TiO2) coatings grown by atomic layer deposition (ALD) have appeared to be a promising approach to stabilize semiconductor photoanodes under PEC conditions. In particular, amorphous ALD grown TiO2 has shown exceptional charge transfer properties compared to its crystalline form that are not properly understood yet. Therefore, we target to gain better understanding on the defect structure of ALD grown TiO2 and utilize the information in the development of optimal photoanode protection layer for efficient solar water splitting.

In this work, structural, optical and photoelectrochemical properties of the ALD grown TiO2 films were studied in as-deposited condition and after annealing in air at 500 °C. TiO2 films were grown on n-type phosphorus-doped silicon and fused quartz by ALD at 200 °C using tetrakis(dimethylamido)titanium (TDMAT) and deionized water as precursors. The properties of TiO2 were investigated by X-ray photoelectron spectroscopy (XPS), ellipsometry and UV/Vis/NIR spectrophotometry. In addition, results from X-ray diffraction (XRD), Raman spectroscopy and photoelectrochemical (PEC) cell are discussed.

Based on the results, as-deposited TiO2 is amorphous and absorbs visible light as ''black'' TiO2. After annealing in air at 500 °C TiO2 crystallizes as rutile and becomes ''white'' TiO2 that absorbs light only in the UV region. As-deposited TiO2 contains significant amount of Ti3+/2+ oxygen vacancies that are oxidized as Ti4+ upon annealing in air. In addition, nitrogen is found only in as-deposited titanium dioxide. As-deposited TiO2 is not chemically stable under PEC conditions. In contrast, the annealed TiO2 is chemically stable and showed 0.20 % ABPE efficiency for water splitting reaction.

As a conclusion, Ti3+ defects induce photocorrosion of ALD TiO2 under PEC conditions. After annealing in air at 500 °C ALD TiO2 is chemically stable and it can be used as a photoanode protection layer. In the future, research will be focused on optimizing the properties of ALD TiO2/Si interface and studying the structure of the surface after deposition of nickel electrocatalysts on TiO2/Si photoanode.

General information

Publication status: Published
Organisations: Photonics, Research group: Surface Science
Contributors: Saari, J., Ali-Löytty, H., Valden, M.
Publication date: 29 May 2018
Peer-reviewed: Unknown
Event: Paper presented at Optics & Photonics Days 2018, Jyväskylä, Finland.
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Surfaces, Coatings and Films
Keywords: Atomic layer deposition, Titanium dioxide, Photoelectrochemical water splitting

Research output: Other conference contributionPaper, poster or abstractScientific

Inoculum pretreatment differentially affects the active microbial community performing mesophilic and thermophilic dark fermentation of xylose

The influence of different inoculum pretreatments (pH and temperature shocks) on mesophilic (37 °C) and thermophilic (55 °C) dark fermentative H2 production from xylose (50 mM) and, for the first time, on the composition of the active microbial community was evaluated. At 37 °C, an acidic shock (pH 3, 24 h) resulted in the highest yield of 0.8 mol H2 mol−1 xylose. The H2 and butyrate yield correlated with the relative abundance of Clostridiaceae in the mesophilic active microbial community, whereas Lactobacillaceae were the most abundant non-hydrogenic competitors according to RNA-based analysis. At 55 °C, Clostridium and Thermoanaerobacterium were linked to H2 production, but only an alkaline shock (pH 10, 24 h) repressed lactate production, resulting in the highest yield of 1.2 mol H2 mol−1 xylose. This study showed that pretreatments differentially affect the structure and productivity of the active mesophilic and thermophilic microbial community developed from an inoculum.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Natl. University of Ireland, Galway, ENEA/CREATE/Università Degli Studi Napoli Federico II, University of Cassino and Southern Lazio, Institute for Water Education, UNESCO–IHE
Contributors: Dessì, P., Porca, E., Frunzo, L., Lakaniemi, A., Collins, G., Esposito, G., Lens, P. N.
Pages: 9233-9245
Publication date: 10 May 2018
Peer-reviewed: Yes
Early online date: 1 Jan 2018

Publication information

Journal: International Journal of Hydrogen Energy
Volume: 43
Issue number: 19
ISSN (Print): 0360-3199
Ratings: 
  • Scopus rating (2018): CiteScore 6.8 SJR 1.1 SNIP 1.166
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Condensed Matter Physics, Energy Engineering and Power Technology
Keywords: Biohydrogen, Clostridium, Lactobacillus, MiSeq, pH shock, Temperature shock
Source: Scopus
Source ID: 85045538153

Research output: Contribution to journalArticleScientificpeer-review

Investigating the kinetics and biofuel properties of Alstonia congensis and Ceiba pentandra via torrefaction

Alstonia congensis (Ahun) and Ceiba pentandra (Araba) were chosen as representations of tropical wood in this study. The use of untreated wood for energy recovery could lead to a high loss in efficiency. One way of circumventing this in a developing country such as Nigeria is by exposing the fuel materials to a pre-treatment, such as torrefaction, prior to deployment. Attempts were made to improve the combustion properties of these resources and also to investigate their torrefaction kinetics. Derivations of kinetic parameters using Coats-Redfern method were discontinued due to inconsistent results. A non-linear regression method was then employed and the results compared to the average value obtained by the FWO method, which was considered more viable than the Coats-Redfern method. The kinetic parameters (Ea,A and n) derived by the regression method are 134.45 kJ/mol, 1.83E+13 min−1 and 2.15, respectively, for Araba and 143.38 kJ/mol, 1.90E+10 min−1 and 2.28, respectively, for Ahun. The thermal behaviour of the samples showed that a lower mass yield resulted in a lower energy yield, while the heating values increased with the temperature of torrefaction. The results obtained in this study affirm the possibility of obtaining an optimum conversion of these resources for energy recovery.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, University of Borås, Laboratory of Chemistry and Bioengineering
Contributors: Oluoti, K., Doddapaneni, T. R. K., Richards, T.
Number of pages: 8
Pages: 134-141
Publication date: 1 May 2018
Peer-reviewed: Yes

Publication information

Journal: Energy
Volume: 150
ISSN (Print): 0360-5442
Ratings: 
  • Scopus rating (2018): CiteScore 8.5 SJR 2.048 SNIP 1.842
Original language: English
ASJC Scopus subject areas: Civil and Structural Engineering, Building and Construction, Pollution, Energy(all), Mechanical Engineering, Industrial and Manufacturing Engineering, Electrical and Electronic Engineering
Keywords: Alstonia congensis, Ceiba pentandra, Energy densification, Kinetic parameters, Mini-grid, Torrefaction
Source: Scopus
Source ID: 85042679330

Research output: Contribution to journalArticleScientificpeer-review

Coordinated voltage control as a replacement for passive network reinforcements-A case study

The paper presents the results of a case study conducted on a real-life distribution system, in which an active network management solution is compared against passive network reinforcements. A methodology for assessing the hosting capacity of medium voltage network for distributed generation is presented and results of two calculation cases (Active Network Management and equivalent passive investment) are compared from investment cost-benefit perspective. The results of the paper show significant economic benefits in Active Network Management based solutions against passive reinforcements.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering, VTT Technical Research Centre of Finland
Contributors: Supponen, A., Repo, S., Kulmala, A.
Number of pages: 6
Pages: 326-331
Publication date: 17 Apr 2018

Host publication information

Title of host publication: 2017 IEEE International Conference on Smart Grid Communications, SmartGridComm 2017
Publisher: IEEE
ISBN (Electronic): 9781538640555
ASJC Scopus subject areas: Artificial Intelligence, Computer Networks and Communications, Energy Engineering and Power Technology, Safety, Risk, Reliability and Quality
Keywords: Active Network Management, Coordinated Voltage Control, Distributed Generation, Hosting Capacity Assessment

Bibliographical note

INT=eee,"Supponen, Antti"
EXT="Kulmala, Anna"

Source: Scopus
Source ID: 85050893763

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Policy Influence on Consumers’ Evolution into Prosumers—Empirical Findings from an Exploratory Survey in Europe

The energy sector is in transition to a flexible and sustainable energy system based on renewable energy sources. This complex transition is affecting multiple levels in the sociotechnical system. One driver of the transition is climate change that enforces the policy push from the macro level to change the way energy is produced, delivered, and used. As part of the energy system evolution, the role of the end user in the energy sector is undergoing profound changes, and consumers are increasingly being empowered to participate actively in the production and use of energy. This article investigates how policies might affect consumers’ interests in becoming prosumers of energy. We explore consumers’ attitudes toward using renewable energy technologies (RET) by means of an empirical consumer survey that was conducted in five European countries. The partial least squares structural equation modeling (PLS-SEM) method was utilized to analyze the survey results. Our findings suggest that both economic and non-economic policies affect consumer attitudes toward using renewable energy technologies. We conclude that policies have different effects on consumers and prosumers, who have already made the decision to adopt renewable energy solutions. Based on the findings, we propose a set of policy and managerial implications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Industrial and Information Management, Research group: Center for Innovation and Technology Research, University of Lausanne
Contributors: Kotilainen, K., Saari, U. A.
Number of pages: 22
Publication date: 13 Jan 2018
Peer-reviewed: Yes

Publication information

Journal: Sustainability
Volume: 2018
Issue number: 10
Article number: 186
ISSN (Print): 2071-1050
Ratings: 
  • Scopus rating (2018): CiteScore 2.8 SJR 0.549 SNIP 1.201
Original language: English
ASJC Scopus subject areas: Management Science and Operations Research, Management of Technology and Innovation, Environmental Science(all), Energy(all)
Keywords:  energy policy, PLS-SEM, diffusion, Technology Acceptance, prosumer, consumer, renewable energy technology
Electronic versions: 

Research output: Contribution to journalArticleScientificpeer-review

A new method to assess the contribution of VSC-HVDC connected wind farms to the primary frequency control of power networks

This paper introduces a new method to assess the contribution of VSC-HVDC connected wind farms to the primary frequency control (PFC) of power networks. This is a formulation that enables the estimation of the post-disturbance conditions of the power system, including its electrical frequency, after the incidence of power imbalances, where various VSC-HVDC connected wind farms may be simultaneously simulated. As opposed to a full dynamic simulation, which may be time-consuming, the developed method resorts to modelling all power system components for the PFC time frame by using enhanced steady-state power-flow models which are solved for a power system operating point that agrees well with the operating conditions of the network after the action of the PFC. Therefore, models of DFIG and PMSG are first derived by following a proposed procedure for the determination of the frequency regulation of the wind turbines, often called statism, whose value varies with the wind speed, as opposed to that of conventional power plants which is constant. Because the power reserve of the wind generators is used to counteract the frequency deviations in the AC power network, a VSC-HVDC link model is also developed which enables a free power transfer to conform to the output power of the wind farm. The proposed method is validated using a 9-bus power system comprising a 120-MW VSC-HVDC connected wind farm and whose results are compared against those computed by a full time-domain dynamic simulation, obtaining a very good agreement between the two quite distinct approaches where, for instance, the post-disturbance system frequency computed by the proposed method only differs by 0.092% with respect to that obtained by the full dynamic simulation. The IEEE 57-bus test system, slightly modified to incorporate two VSC-HVDC connected wind farms, is also simulated to show that the impact of the frequency regulation of the wind farms on the PFC may be assessed in a very quick, effective manner.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Energy Engineering, Department of Electrical Engineering
Contributors: Castro, L. M., Acha, E.
Number of pages: 11
Pages: 48-58
Publication date: 2018
Peer-reviewed: Yes
Early online date: 1 Sep 2017

Publication information

Journal: Electric Power Systems Research
Volume: 154
ISSN (Print): 0378-7796
Ratings: 
  • Scopus rating (2018): CiteScore 6.4 SJR 1.037 SNIP 1.444
Original language: English
ASJC Scopus subject areas: Energy Engineering and Power Technology, Electrical and Electronic Engineering
Keywords: DFIG, Newton–Raphson method, PMSG, Post-disturbance conditions, Power imbalances, Primary frequency control, Variable speed wind turbines, VSC-HVDC links, Wind farms
Source: Scopus
Source ID: 85028060536

Research output: Contribution to journalArticleScientificpeer-review

A novel strategy for optimal placement of locally controlled voltage regulators in traditional distribution systems

In this paper, an approach for placement of voltage regulators (VRs) in traditional distribution systems by considering a local controller model is presented. The main aims of this paper are controlling the voltage level in its permitted range and decreasing the costs imposed to the distribution system companies, such as costs that stem from power losses, VRs’ investment and maintenance. Genetic algorithm (GA) has been used as a tool to determine the number, location and rated power of VRs. Since in traditional distribution systems, tap position determination of VRs is achieved by local controllers, local controller model is established to determine tap operations. A 70-bus distribution system is considered to prove the value of the presented approach. Effectiveness of the proposed approach and ineffectiveness and infeasibility of conventional approaches are presented in numerical studies. The presented approach allowed to eliminate voltage violation in all load conditions and a reduction of power losses of about 6% for the maximum load level.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Energy Engineering, Iran University of Science and Technology, University of Birjand, Università di Salerno
Contributors: Attar, M., Homaee, O., Falaghi, H., Siano, P.
Number of pages: 12
Pages: 11-22
Publication date: 2018
Peer-reviewed: Yes
Early online date: 29 Sep 2017

Publication information

Journal: International Journal of Electrical Power and Energy Systems
Volume: 96
ISSN (Print): 0142-0615
Ratings: 
  • Scopus rating (2018): CiteScore 9.4 SJR 1.26 SNIP 2.058
Original language: English
ASJC Scopus subject areas: Energy Engineering and Power Technology, Electrical and Electronic Engineering
Keywords: Distribution systems planning, Genetic algorithm, Local controller, Set point, Tap position, Voltage regulator
Source: Scopus
Source ID: 85030472698

Research output: Contribution to journalArticleScientificpeer-review

Dynamic modeling and analysis of PCM-controlled DCM-operating buck converters-A reexamination

Peak-current-mode (PCM) control was proposed in 1978. The observed peculiar behavior caused by the application of PCM-control in the behavior of a switched-mode converter, which operates in continuous conduction mode (CCM), has led to a multitude of attempts to capture the dynamics associated to it. Only a few similar models have been published for a PCM-controlled converter, which operates in discontinuous conduction mode (DCM). PCM modeling is actually an extension of the modeling of direct-duty-ratio (DDR) or voltage-mode (VM) control, where the perturbed duty ratio is replaced by proper duty-ratio constraints. The modeling technique, which produces accurate PCM models in DCM, is developed in early 2000s. The given small-signal models are, however, load-resistor affected, which hides the real dynamic behavior of the associated converter. The objectives of this paper are as follows: (i) proving the accuracy of the modeling method published in 2001, (ii) performing a comprehensive dynamic analysis in order to reveal the real dynamics of the buck converter under PCM control in DCM, (iii) providing a method to improve the high-frequency accuracy of the small-signal models, and (iv) developing control-engineering-type block diagrams to facilitate the development of generalized transfer functions, which are applicable for PCM-controlled DCM-operated buck, boost, and buck-boost converters.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Electrical Energy Engineering, Research group: Power electronics, Research area: Power engineering
Contributors: Suntio, T.
Number of pages: 18
Pages: 1-18
Publication date: 2018
Peer-reviewed: Yes
Early online date: 15 May 2018

Publication information

Journal: Energies
Volume: 11
Issue number: 5
Article number: en11051267
ISSN (Print): 1996-1073
Ratings: 
  • Scopus rating (2018): CiteScore 3.3 SJR 0.612 SNIP 1.186
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Energy (miscellaneous), Control and Optimization, Electrical and Electronic Engineering
Keywords: Discontinuous conduction mode, Duty-ratio constraints, Dynamic modeling, Peak-current-mode control
Electronic versions: 
Source: Scopus
Source ID: 85054989951

Research output: Contribution to journalReview ArticleScientificpeer-review

Improved Light Trapping in Quantum Dot Solar Cells Using Double-sided Nanostructuring

We investigate light trapping in thin-film quantum dot solar cells employing front and back side nanostructuring for antireflection and diffraction, respectively. Simulation results demonstrate a large improvement of the effective quantum dot optical absorption.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Photonics, Research group: ORC, Politecnico di Torino
Contributors: Elsehrawy, F., Aho, T., Niemi, T., Guina, M., Cappelluti, F.
Number of pages: 2
Publication date: 2018

Host publication information

Title of host publication: Optics and Photonics for Energy and the Environment 2018
Publisher: OSA - The Optical Society
ISBN (Electronic): 978-1-943580-47-7
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Light-trapping enhanced thin-film III-V quantum dot solar cells fabricated by epitaxial lift-off

We report thin-film InAs/GaAs quantum dot (QD) solar cells with n-i-p+ deep junction structure and planar back reflector fabricated by epitaxial lift-off (ELO) of full 3-in wafers. External quantum efficiency measurements demonstrate twofold enhancement of the QD photocurrent in the ELO QD cell compared to the wafer-based QD cell. In the GaAs wavelength range, the ELO QD cell perfectly preserves the current collection efficiency of the baseline single-junction ELO cell. We demonstrate by full-wave optical simulations that integrating a micro-patterned diffraction grating in the ELO cell rearside provides more than tenfold enhancement of the near-infrared light harvesting by QDs. Experimental results are thoroughly discussed with the help of physics-based simulations to single out the impact of QD dynamics and defects on the cell photovoltaic behavior. It is demonstrated that non radiative recombination in the QD stack is the bottleneck for the open circuit voltage (Voc) of the reported devices. More important, our theoretical calculations demonstrate that the Voc offset of 0.3. V from the QD ground state identified by Tanabe et al., 2012, from a collection of experimental data of high quality III-V QD solar cells is a reliable - albeit conservative - metric to gauge the attainable Voc and to quantify the scope for improvement by reducing non radiative recombination. Provided that material quality issues are solved, we demonstrate - by transport and rigorous electromagnetic simulations - that light-trapping enhanced thin-film cells with twenty InAs/GaAs QD layers reach efficiency higher than 28% under unconcentrated light, ambient temperature. If photon recycling can be fully exploited, 30% efficiency is deemed to be feasible.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, Research group: ORC, Research group: Nanophotonics, Politecnico di Torino, Department of Applied Health Research, Radboud University Nijmegen, tf2 devices B.V.
Contributors: Cappelluti, F., Kim, D., van Eerden, M., Cédola, A. P., Aho, T., Bissels, G., Elsehrawy, F., Wu, J., Liu, H., Mulder, P., Bauhuis, G., Schermer, J., Niemi, T., Guina, M.
Pages: 83-92
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: Solar Energy Materials and Solar Cells
Volume: 181
ISSN (Print): 0927-0248
Ratings: 
  • Scopus rating (2018): CiteScore 10.2 SJR 1.62 SNIP 1.681
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Renewable Energy, Sustainability and the Environment, Surfaces, Coatings and Films
Keywords: Epitaxial lift-off, Light-trapping, Quantum dot, Solar cell, Thin-film
Source: Scopus
Source ID: 85039853836

Research output: Contribution to journalArticleScientificpeer-review

Techno-economic evaluation of integrating torrefaction with anaerobic digestion

In recent days, the interest on torrefaction is increasing owing to its ability to improve biomass properties to a level of competing with coal. However, its techno-economic feasibility still need to be optimized. Integrating torrefaction with other thermochemical and biochemical processes could be a feasible option to improve the performance of the torrefaction process. In that regard, this study evaluates the techno-economic feasibility of integrating the torrefaction with anaerobic digestion (AD). In addition, new process configurations were studied to identify the possible heat energy recovery options. Technical feasibility was tested through mass and energy balance at each process unit. The economic indicators such as net present value (€), minimum selling price and internal rate on return (%) were used to evaluate the economic performance. At 10 t/h of torrefied biomass pellets production capacity, the estimated bio-methane production from AD was 369 m3/h. The economic evaluation shows that the minimum selling price of the torrefied biomass to reach the breakeven could be reduced from 199 €/t for standalone torrefaction to 185 €/t in case of torrefaction integrated with AD. The sensitivity analysis shows that feedstock and total capital investment were the most sensitive input parameters. This study shows that integrating the torrefaction with AD has better technical and economic feasibility than standalone torrefaction.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Doddapaneni, T. R. K. C., Praveenkumar, R., Tolvanen, H., Rintala, J., Konttinen, J.
Number of pages: 13
Pages: 272-284
Publication date: 2018
Peer-reviewed: Yes
Early online date: Jan 2018

Publication information

Journal: Applied Energy
Volume: 213
ISSN (Print): 0306-2619
Ratings: 
  • Scopus rating (2018): CiteScore 14.3 SJR 3.455 SNIP 2.649
Original language: English
ASJC Scopus subject areas: Civil and Structural Engineering, Building and Construction, Energy(all), Mechanical Engineering, Management, Monitoring, Policy and Law
Keywords: Energy recovery, Minimum selling price, Process integration, Techno-economic analysis, Torrefaction – anaerobic digestion, Torrefied pellets
Source: Scopus
Source ID: 85041461877

Research output: Contribution to journalArticleScientificpeer-review

Thermophilic versus mesophilic dark fermentation in xylose-fed fluidised bed reactors: Biohydrogen production and active microbial community

Dark fermentative biohydrogen production in a thermophilic, xylose-fed (50 mM) fluidised bed reactor (FBR) was evaluated in the temperature range 55-70 °C with 5-degree increments and compared with a mesophilic FBR operated constantly at 37 °C. A significantly higher (p = 0.05) H2 yield was obtained in the thermophilic FBR, which stabilised at about 1.2 mol H2 mol-1 xylose (36% of the theoretical maximum) at 55 and 70 °C, and at 0.8 mol H2 mol-1 xylose at 60 and 65 °C, compared to the mesophilic FBR (0.5 mol H2 mol-1 xylose). High-throughput sequencing of the reverse-transcribed 16S rRNA, done for the first time on biohydrogen producing reactors, indicated that Thermoanaerobacterium was the prevalent active microorganism in the thermophilic FBR, regardless of the operating temperature. The active microbial community in the mesophilic FBR was mainly composed of Clostridium and Ruminiclostridium at 37 °C. Thermophilic dark fermentation was shown to be suitable for treatment of high temperature, xylose-containing wastewaters, as it resulted in a higher energy output compared to the mesophilic counterpart.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Natl. University of Ireland, Galway, The James Hutton Institute, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education
Contributors: Dessì, P., Porca, E., Waters, N. R., Lakaniemi, A., Collins, G., Lens, P. N.
Pages: 5473-5485
Publication date: 2018
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: International Journal of Hydrogen Energy
Volume: 43
Issue number: 11
ISSN (Print): 0360-3199
Ratings: 
  • Scopus rating (2018): CiteScore 6.8 SJR 1.1 SNIP 1.166
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Condensed Matter Physics, Energy Engineering and Power Technology
Keywords: Active community, Biohydrogen, FBR, MiSeq, Thermoanaerobacterium, Thermophilic
Source: Scopus
Source ID: 85042365131

Research output: Contribution to journalArticleScientificpeer-review

Carbazole-based small molecule electron donors: Syntheses, characterization, and material properties

Efficient synthetic methods for carbazole-based small molecule electron donors with donor–acceptor (D–A) and A–D–A type structures were developed. In order to study the relation between chemical structures and material properties, the prepared compounds were characterized in detail using absorption spectroscopy, differential pulse voltammetry, and computational methods. In addition, symmetrical A–D–A type compounds were tested as an active layer component in bulk heterojunction based organic solar cell (OSC) devices with conventional structure. The results show that the two compound types have many similar properties. However, the extended molecular structure of A–D–A type compounds offer better film forming properties and higher molar absorption coefficients compared with the D–A type materials. Furthermore, the attachment of fluoro substituents in the A units has a positive effect on all solar cell device parameters. Moreover, the computational studies revealed that the molecular structures are twisted between the central carbazole D unit and π-bridge which may result in inefficient intramolecular charge transfer and, also, relatively limited short-circuit currents in OSC devices.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Research group: Chemistry & Advanced Materials, Research Unit of Sustainable Chemistry, IMEC PV Department
Contributors: Sippola, R. J., Hadipour, A., Kastinen, T., Vivo, P., Hukka, T. I., Aernouts, T., Heiskanen, J. P.
Number of pages: 10
Pages: 79-88
Publication date: 8 Nov 2017
Peer-reviewed: Yes
Early online date: 8 Nov 2017

Publication information

Journal: Dyes and Pigments
Volume: 150
Article number: j.dyepig.2017.11.014
ISSN (Print): 0143-7208
Ratings: 
  • Scopus rating (2017): CiteScore 5.6 SJR 0.819 SNIP 1.009
Original language: English
ASJC Scopus subject areas: Chemistry(all), Energy(all)
Keywords: Absorption, DFT, Electron donor, Organic solar cell, Suzuki-Miyaura, Synthesis
Electronic versions: 
URLs: 

Research output: Contribution to journalArticleScientificpeer-review

Effect of hydraulic retention time on continuous electricity production from xylose in up-flow microbial fuel cell

Aerobic wastewater management is energy intensive and thus anaerobic processes are of interest. In this study, a microbial fuel cell was used to produce electricity from xylose which is an important constituent of lignocellulosic waste. Hydraulic retention time (HRT) was optimized for the maximum power density by gradually decreasing the HRT from 3.5 d to 0.17 d. The highest power density (430 mW/m2) was obtained at 1 d HRT. Coulombic efficiency decreased from 30% to 0.6% with HRTs of 3.5 d and 0.17 d, respectively. Microbial community analysis revealed that anode biofilm contained known exoelectrogens, including Geobacter sp. and fermentative organisms were present in both anolyte and the anode biofilm. The peak power densities were obtained at 1-1.7 d HRTs and xylose degraded almost completely even with the lowest HRT of 0.17 d, which demonstrates the efficiency of up-flow MFC for treating synthetic wastewater containing xylose.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Feng Chia University
Contributors: Haavisto, J. M., Kokko, M. E., Lay, C., Puhakka, J. A.
Pages: 27494-27502
Publication date: 1 Nov 2017
Peer-reviewed: Yes

Publication information

Journal: International Journal of Hydrogen Energy
Volume: 42
ISSN (Print): 0360-3199
Ratings: 
  • Scopus rating (2017): CiteScore 6.3 SJR 1.116 SNIP 1.322
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Condensed Matter Physics, Energy Engineering and Power Technology
Keywords: Continuous operation, Hydraulic retention time, Microbial community, Microbial fuel cell, Up-flow, Xylose
URLs: 

Bibliographical note

EXT="Lay, Chyi-How"

Source: Scopus
Source ID: 85019734862

Research output: Contribution to journalArticleScientificpeer-review

Koulujen ja päiväkotien laskettu ja toteutunut energiankulutus

General information

Publication status: Published
MoE publication type: B3 Non-refereed article in conference proceedings
Organisations: Civil Engineering, Research group: Building Physics
Contributors: Ruusala, A., Vinha, J.
Number of pages: 8
Pages: 267-274
Publication date: 24 Oct 2017

Host publication information

Title of host publication: Rakennusfysiikka 2017. Uusimmat tutkimustulokset ja hyvät käytännön ratkaisut : 24.-26.10.2017, Tampere
Volume: 1
Place of publication: Tampere
Publisher: Tampereen teknillinen yliopisto, Rakennustekniikka, Rakennusfysiikka
Editors: Vinha, J., Kivioja, H.
ISBN (Print): 978-952-15-4022-6

Publication series

Name: Tampereen teknillinen yliopisto. Rakennustekniikka. Rakennusfysiikka.
ASJC Scopus subject areas: Engineering(all), Energy(all)

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientific

Kustannusoptimaaliset energiakorjaus- ja uusiutuvan energian tuotannon ratkaisut kunnallisissa palvelurakennuksissa

General information

Publication status: Published
MoE publication type: B3 Non-refereed article in conference proceedings
Organisations: Civil Engineering, Research group: Building Physics, Aalto Univ, Aalto University, Sch Engn, Dept Energy Technol, Equa Simulation Finland Oy
Contributors: Jokisalo, J., Sankelo, P., Sirén, K., Vinha, J.
Number of pages: 6
Pages: 287-292
Publication date: 24 Oct 2017

Host publication information

Title of host publication: Rakennusfysiikka 2017. Uusimmat tutkimustulokset ja hyvät käytännön ratkaisut : 24.-26.10.2017, Tampere
Volume: 1
Place of publication: Tampere
Publisher: Tampereen teknillinen yliopisto, Rakennustekniikka, Rakennusfysiikka
Editors: Vinha, J., Kivioja, H.
ISBN (Print): 978-952-15-4022-6
ASJC Scopus subject areas: Engineering(all), Energy(all)

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientific

A demand-based nutrient utilization approach to urban biogas plant investment based on regional crop fertilization

This study aimed to develop a regional nutrient demand-based approach to assess the potential use of digestate nutrients from a planned biogas plant investment as a part of a regional circular economy concept. The assumed biogas plant is expected to treat urban wastes; biowastes (23,500 t/y) and sewage sludges (120,000 t/y) from the Tampere region, Finland (total population of 500,000). The calculation of the regional nutrient balance was based on the fertilizable crop areas, fertilization regimes and biomass nutrient amounts, with an assumption that livestock manures were primarily utilized in crop production. Subsequently, a Geographic Information System (GIS)-based methodology was applied to evaluate the transportation distances of nutrients from the biogas plant to the closest crop fields. As a result from the presented approach, livestock manure covered 41% and 12% of the phosphorus (P) and soluble nitrogen (N) need of the studied region. There was a residual potential for the regional utilization of biogas plant nutrients, which together with the livestock manure accounted for 50% of P and 15% of soluble-N need. Transportation of nutrients up to 40 km from the biogas plant is necessary if all nearby fields receive the waste-based nutrients, while the distance increased to 66 km if 30% of the local farmers are willing to use the nutrients. The approach presented in this study acts as a tool for planning nutrient cycles, which can be used to sustainably manage the regional nutrient flows when planning a new biogas plant investment.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Natural Resources Institute Finland (Luke)
Contributors: Tampio, E., Lehtonen, E., Kinnunen, V., Mönkäre, T., Ervasti, S., Kettunen, R., Rasi, S., Rintala, J.
Number of pages: 11
Pages: 19-29
Publication date: 15 Oct 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Cleaner Production
Volume: 164
ISSN (Print): 0959-6526
Ratings: 
  • Scopus rating (2017): CiteScore 7.7 SJR 1.467 SNIP 2.383
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Environmental Science(all), Strategy and Management, Industrial and Manufacturing Engineering
Keywords: Biogas plant, Biowaste, Digestate, Livestock manure, Nutrient recycling, Sewage sludge

Bibliographical note

EXT="Tampio, Elina"

Source: Scopus
Source ID: 85027488845

Research output: Contribution to journalArticleScientificpeer-review

Atomikerroskasvatusmenetelmällä kasvatetun titaanidioksidikalvon ominaisuudet valosähkökemiallisessa veden hajottamisessa

Photoelectrochemical water splitting is one of the potential ways of utilizing solar energy. A major issue for the method and for renewable energy production would be the development of an efficient and a cost-effective semiconductor photoanode. In this Master of Science Thesis properties of atomic layer deposited (ALD) titanium dioxide film (TiO2), such as a chemical composition, a crystal structure and the ability to absorb sunlight, are studied in as-deposited conditions and after oxidative annealing. By understanding thoroughly the properties of atomic layer deposited titanium dioxide and the effects of post-annealing in air, titanium dioxide can be better utilized in semiconductor photoanodes used in photoelectrochemical water splitting.

Titanium dioxide films examined in this study were grown on n-type phosphorus-doped silicon (n-Si(100)(P)) and fused quartz used as substrates by atomic layer deposition at 200 °C using tetrakis(dimethylamido)titanium (TDMAT) and deionized water as precursors. The annealing of some of the samples at 500 °C in air was made in a tube furnace. The concentrations of the elements and chemical states of the atomic layer deposited titanium dioxide films were studied by X-ray photoelectron spectroscopy (XPS). The film thickness and refractive index were determined by ellipsometer and the absorption properties of the titanium dioxide film were measured by UV/Vis/NIR spectrophotometer. In addition, crystallographic results from X-ray diffraction (XRD) and Raman spectroscopy were also utilized, as well as the results of the photoelectrochemical cell and solar simulator on titanium dioxide photoanode performance.

Based on the results, at 200 °C atomic layer deposited titanium dioxide is amorphous and absorbs visible light as ”black” TiO2. At the oxidative annealing at 500 °C titanium dioxide crystallizes into rutile and becomes ”white” TiO2 that absorbs less visible light. Both titanium dioxide films contain the lower Ti3+/2+ oxidation states of titanium that may indicate oxygen vacancies. Nitrogen is found only in as-deposited titanium dioxide. The annealed titanium dioxide is stable in electrolyte, achieving 0.20 % ABPE for water splitting reaction.

General information

Publication status: Published
MoE publication type: G2 Master's thesis, polytechnic Master's thesis
Organisations: Photonics, Research group: Surface Science
Contributors: Saari, J.
Number of pages: 74
Publication date: 4 Oct 2017

Publication information

Original language: Finnish
ASJC Scopus subject areas: Surfaces, Coatings and Films, Renewable Energy, Sustainability and the Environment
Keywords: Photoelectrochemical water splitting, Titanium dioxide, ALD, Atomic layer deposition, XPS, X-ray photoelectron spectroscopy, Ellipsometry, UV/Vis/NIR spectrophotometry

Research output: Book/ReportMaster's ThesisScientific

Real-time hardware- and software-in-the-loop simulation of decentralised distribution network control architecture

This study introduces a laboratory test set up developed to evaluate the functionality of a novel decentralised distribution automation architecture. The demonstration system consists of a simulated distribution network in real-time simulation environment including simulated monitoring and control devices as well as physical devices interfaced with the simulator as hardware-in-the-loop test devices. System involves also substation automation units for real-time monitoring and control that are interfaced with the simulator and physical devices. The operating principle of the system is demonstrated with an example simulation case. The main goal for this system was to test the functionality of the decentralised distribution automation architecture and track out any potential interfacing issues of automation system before implementing the concept to actual field demonstrations. Based on the tests executed with the system described in this study, the proper functionality of all the features of the automation architecture was verified and successfully deployed at the field test sites.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Energy Engineering, Research group: Power systems, VTT Technical Research Centre of Finland
Contributors: Tuominen, V., Reponen, H., Kulmala, A., Lu, S., Repo, S.
Number of pages: 8
Pages: 3057-3064
Publication date: 24 Aug 2017
Peer-reviewed: Yes

Publication information

Journal: IET Generation, Transmission and Distribution
Volume: 11
Issue number: 12
ISSN (Print): 1751-8687
Ratings: 
  • Scopus rating (2017): CiteScore 4 SJR 0.907 SNIP 1.355
Original language: English
ASJC Scopus subject areas: Control and Systems Engineering, Energy Engineering and Power Technology, Electrical and Electronic Engineering

Bibliographical note

EXT="Kulmala, Anna"

Source: Scopus
Source ID: 85029745746

Research output: Contribution to journalArticleScientificpeer-review

Exhaust emissions of non-road mobile machine: Real-world and laboratory studies with diesel and HVO fuels

Exhaust emissions emitted by a non-road mobile machine were studied chasing a tractor in real-world conditions and repeating the same transient tests with a similar engine on an engine dynamometer where additionally, non-road steady state tests were carried out. The engines were equipped with an oxidation catalyst (DOC) and a selective catalytic reduction (SCR) system, and they were fuelled by fossil diesel fuel with ultra-low sulphur content and hydrotreated vegetable oil (HVO). By substituting diesel fuel with HVO the on-road emissions of nitrogen oxides (NOx) reduced 20% and particle number 44%, the emission factors being EFNOx = 1.62 ± 0.04 g/kWh and EFN = (28.2 ± 7.8) × 1013 #/kWh. Similar trend was observed for NOx at laboratory although the emissions were somewhat smaller than on-road. In contrast to real-world, in the laboratory experiment the EFN was only 2% smaller with HVO than with diesel, and these emission factors were almost one order of magnitude smaller than observed on-road. The number size distribution and volatility measurements showed that in real-world experiments small nucleation mode particles were formed during uphill and during downhill in engine braking conditions. These were not observed at laboratory. However, nucleation mode particles were observed in the laboratory experiments at high load steady driving conditions. At steady state tests the emissions strongly depended on engine load and engine speed with both fuels.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Research area: Aerosol Physics, University of Helsinki, Turku University of Applied Sciences
Contributors: Pirjola, L., Rönkkö, T., Saukko, E., Parviainen, H., Malinen, A., Alanen, J., Saveljeff, H.
Number of pages: 11
Pages: 154-164
Publication date: 15 Aug 2017
Peer-reviewed: Yes

Publication information

Journal: Fuel
Volume: 202
ISSN (Print): 0016-2361
Ratings: 
  • Scopus rating (2017): CiteScore 8.8 SJR 1.891 SNIP 2.127
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Fuel Technology, Energy Engineering and Power Technology, Organic Chemistry
Keywords: Diesel engine, Exhaust emissions, HVO, NO, Particle size distribution, Real-world emissions, Tractor
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 85017566506

Research output: Contribution to journalArticleScientificpeer-review

Electropolymerized polyazulene as active material in flexible supercapacitors

We report the capacitive behavior of electrochemically polymerized polyazulene films in different ionic liquids. The ionic liquids in this study represent conventional imidazolium based ionic liquids with tetrafluoroborate and bis(trifluoromethylsulfonyl)imide anions as well as an unconventional choline based ionic liquid. The effect of different ionic liquids on the polymerization and capacitive performance of polyazulene films is demonstrated by cyclic voltammetry and electrochemical impedance spectroscopy in a 3-electrode cell configuration. The films exhibit the highest capacitances in the lowest viscosity ionic liquid (92 mF cm−2), while synthesis in high viscosity ionic liquid shortens the conjugation length and results in lower electroactivity (25 mF cm−2). The obtained films also show good cycling stabilities retaining over 90% of their initial capacitance over 1200 p-doping cycles. We also demonstrate, for the first time, flexible polyazulene supercapacitors of symmetric and asymmetric configurations using the choline based ionic liquid as electrolyte. In asymmetric configuration, capacitance of 55 mF (27 mF cm−2) with an equivalent series resistance of 19 Ω is obtained at operating voltage of 1.5 V. Upon increasing the operating voltage up to 2.4 V, the capacitance increases to 72 mF (36 mF cm−2).

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electronics and Communications Engineering, Faculty of Biomedical Sciences and Engineering, Research area: Microsystems, Research area: Measurement Technology and Process Control, Research group: Sensor Technology and Biomeasurements (STB), BioMediTech, Turun Yliopisto/Turun Biomateriaalikeskus
Contributors: Suominen, M., Lehtimäki, S., Yewale, R., Damlin, P., Tuukkanen, S., Kvarnström, C.
Number of pages: 10
Pages: 181-190
Publication date: 15 Jul 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Power Sources
Volume: 356
ISSN (Print): 0378-7753
Ratings: 
  • Scopus rating (2017): CiteScore 13.6 SJR 2.202 SNIP 1.557
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Physical and Theoretical Chemistry, Electrical and Electronic Engineering
Keywords: Choline, Electropolymerization, Flexible supercapacitor, Ionic liquid, Polyazulene
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 85019024216

Research output: Contribution to journalArticleScientificpeer-review

Aspects of advancement of distribution tariffs for small consumers in Finland

This paper discusses the development of distribution tariffs of small consumers in Finland. Changes in the electricity sector have created pressures for the Distribution System Operators (DSO) to develop their pricing practices in order to better reflect their cost structures. In this context, power-based distribution tariffs (PBDT) have been seen as a potential direction for development. This paper analyses the EU and Finnish legal framework for distribution tariffs with an aim to identify potential regulatory barriers and incentives for developing PBDTs in Finland. To support this analysis, the paper also provides results of a survey conducted in Finland in 2016 in the EL-TRAN project, reflecting the will of Finnish consumers to improve their ability to affect the distribution fees. The results indicate that the consumers are interested in having this opportunity.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering, Ita-Suomen yliopisto, School of Management (JKK)
Contributors: Lummi, K., Rautiainen, A., Järventausta, P., Huhta, K., Talus, K., Kojo, M.
Publication date: 14 Jul 2017

Host publication information

Title of host publication: 2017 14th International Conference on the European Energy Market, EEM 2017
Publisher: IEEE
ISBN (Electronic): 9781509054992
ASJC Scopus subject areas: Marketing, Energy Engineering and Power Technology, Fuel Technology
Keywords: Electricity distribution pricing, Energy efficiency, Legislation, Power-based distribution tariff

Bibliographical note

jufoid=70631

Source: Scopus
Source ID: 85027141816

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Attractiveness of demand response in the Nordic electricity market - Present state and future prospects

During the past few years demand response (DR) has appeared in the spotlight in a new way. This is due to general technological advancement, development of electricity infrastructure, especially roll-out of smart meters, and rapidly increasing amount of renewable intermittent energy sources. This paper analyzes the attractiveness of DR in the Nordic electricity market. The results show that in many market places the attractiveness of DR is improving in the long term, although variations between different years exist. Two case studies presented in the papers show that DR has economic potential for some of the customers, especially for medium to large actors, but in a large scope, number of obstacles still hinder a wide scale deployment of DR solutions.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering, Research area: Power engineering, Research group: Power systems, VTT Technical Research Centre of Finland
Contributors: Rautiainen, A., Koskela, J., Vilppo, O., Supponen, A., Kojo, M., Toivanen, P., Rinne, E., Järventausta, P.
Publication date: 14 Jul 2017

Host publication information

Title of host publication: 2017 14th International Conference on the European Energy Market, EEM 2017
Publisher: IEEE
ISBN (Electronic): 9781509054992
ASJC Scopus subject areas: Marketing, Energy Engineering and Power Technology, Fuel Technology
Keywords: Demand response, Electricity market

Bibliographical note

INT=eee,"Supponen, A."
EXT="Rinne, E."
jufoid=70631

Source: Scopus
Source ID: 85027168719

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Development options for distribution tariff structures in Finland

In this paper, we study the development options of tariff structures in electricity distribution in Finland. We compare the impacts of three different tariffs from the viewpoints of customers, distribution system operator (DSO), electricity supplier, and society. Analyzed tariffs are (1) energy oriented tariff, which is currently in use, (2) power limit tariff, and (3) power tariff. Based on the analyses, it seems that it is justified to include power based price component in distribution tariff. Generally, the impacts of both analyzed power based tariffs are quite similar. However, it seems that power tariff is a bit stronger candidate. Nevertheless, it should be noted that the benefits of the power-oriented pricing, illustrated in the paper, could be achieved only by well-designed tariff system. Although analyses are based on Finnish case, most of the results are generalizable to other countries also.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering, Lappeenranta University of Technology
Contributors: Honkapuro, S., Haapaniemi, J., Haakana, J., Lassila, J., Belonogova, N., Partanen, J., Lummi, K., Rautiainen, A., Supponen, A., Repo, S., Järventausta, P.
Publication date: 14 Jul 2017

Host publication information

Title of host publication: 2017 14th International Conference on the European Energy Market, EEM 2017
Publisher: IEEE
ISBN (Electronic): 9781509054992
ASJC Scopus subject areas: Marketing, Energy Engineering and Power Technology, Fuel Technology
Keywords: Demand response, Distribution tariffs

Bibliographical note

jufoid=70631
INT=eee,"Supponen, Antti"

Source: Scopus
Source ID: 85027133346

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Understanding consumers' renewable energy behaviour beyond 'homo economicus': An exploratory survey in four European countries

Climate change is putting global pressure for energy consumption and production to move towards sustainable solutions based on clean energy sources. Rapid advancements in technology make energy generation and storage solutions available and affordable for consumers and enable them to become relevant actors in the energy process. The actual success of sustainable energy solutions is however not so much dependent on technological readiness, which is already in place to large extent, but rather on influencing consumer adoption in an impactful way. This article explores consumers' behavioral drivers for the adoption of renewable energy solutions by comparing the economic, ecologic and social preferences of consumers in four European countries.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Industrial and Information Management, Electrical Energy Engineering
Contributors: Kotilainen, K., Valta, J., Mäkinen, S. J., Järventausta, P.
Publication date: 14 Jul 2017

Host publication information

Title of host publication: 2017 14th International Conference on the European Energy Market, EEM 2017
Publisher: IEEE
ISBN (Electronic): 9781509054992
ASJC Scopus subject areas: Marketing, Energy Engineering and Power Technology, Fuel Technology
Keywords: Consumer, Incentives, Policy, Prosumer, Renewable energy

Bibliographical note

jufoid=70631

Source: Scopus
Source ID: 85027150084

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Hafnium oxide thin films as a barrier against copper diffusion in solar absorbers

The thermal stability of copper substrate material used in solar thermal collectors was investigated with and without atomic layer deposited (ALD) hafnium oxide barrier films at temperatures of 200–400 °C. HfO2 films were studied as barriers against thermal diffusion of copper substrate atoms. The ALD HfO2 thin films were deposited in a thermal process at 200 °C using Tetrakis(Dimethylamido)Hafnium(Hf(NMe2)4) and H2O precursors, with 200, 400, and 600 cycles. The Cu substrates with and without HfO2 thin films were aged by means of heat treatment in air. The influence of the HfO2 barriers was determined by optical, microstructural, and morphological analyses before and after the ageing procedures. The optical performance of the HfO2 barriers as a part of solar absorber stack was modelled with CODE Coating Designer. The copper surface without a HfO2 barrier thin film oxidized significantly, which increased thermal emittance and surface roughness. 200 cycles of HfO2 deposition did not result in a completely continuous coating and only provided a little protection against oxidation. Films of 200 and 400 cycles gave continuous coverage and the thickest HfO2 thin film studied, which was deposited from 600 ALD cycles and had a thickness ~50 nm, prevented Cu oxidation and diffusion processes after 2 h heat treatment in air at 300 °C, and retained low thermal emissivity. At 400 °C, diffusion and formation of copper oxide hillocks were observed but the HfO2 thin film significantly retarded the degradation when compared to a Cu substrate without and with thinner barrier layers.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Research group: Surface Engineering, R&D Center for Low-Cost Plasma and Nanotechnology Surface Modifications (CEPLANT), Masaryk University
Contributors: Kotilainen, M., Krumpolec, R., Franta, D., Souček, P., Homola, T., Cameron, D. C., Vuoristo, P.
Number of pages: 7
Pages: 140-146
Publication date: 1 Jul 2017
Peer-reviewed: Yes

Publication information

Journal: Solar Energy Materials and Solar Cells
Volume: 166
ISSN (Print): 0927-0248
Ratings: 
  • Scopus rating (2017): CiteScore 9.2 SJR 1.459 SNIP 1.537
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Renewable Energy, Sustainability and the Environment, Surfaces, Coatings and Films
Keywords: Copper diffusion, Diffusion barrier, HfO thin film, Solar absorber, Thermal ageing
Source: Scopus
Source ID: 85016025672

Research output: Contribution to journalArticleScientificpeer-review

Long-Range Observation of Exciplex Formation and Decay Mediated by One-Dimensional Bridges

We report herein unprecedented long-range observation of both formation and decay of the exciplex state in donor (D)-bridge (B)-acceptor (A) linked systems. Zinc porphyrins (ZnP) as a donor were tethered to single-walled carbon nanotube (SWNT) as an acceptor through oligo(p-phenylene)s (ZnP-phn-SWNT) or oligo(p-xylene)s (ZnP-xyn-1-ph1-SWNT) with systematically varied lengths (n = 1-5) to address the issue. Exponential dependencies of rate constants for the exciplex formation (kFEX) and decay (kDEX) on the edge-to-edge separation distance between ZnP and SWNT through the bridges were unambiguously derived from time-resolved spectroscopies. Distance dependencies (i.e., attenuation factor, β) of kFEX and kDEX in ZnP-phn-SWNT were found to be considerably small (β = 0.10 for kFEX and 0.12 Å-1 for kDEX) compared to those for charge separation and recombination (0.2-0.8 Å-1) in D-B-A systems with the same oligo(p-phenylene) bridges. The small β values may be associated with the exciplex state with mixed characters of charge-transfer and excited states. In parallel, the substantially nonconjugated bridge of oligo(p-xylene)s exhibited larger attenuation values (β = 0.12 for kFEX and 0.14 Å-1 for kDEX). These results provide deep insight into the unique photodynamics of electronically strongly coupled D-B-A systems involving exciplex.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Kyoto Women's University
Contributors: Baek, J., Umeyama, T., Stranius, K., Yamada, H., Tkachenko, N. V., Imahori, H.
Number of pages: 10
Pages: 13952-13961
Publication date: 29 Jun 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 121
Issue number: 25
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2017): CiteScore 7.9 SJR 2.135 SNIP 1.133
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Energy(all), Surfaces, Coatings and Films, Physical and Theoretical Chemistry
Source: Scopus
Source ID: 85022231305

Research output: Contribution to journalArticleScientificpeer-review

CFD based reactivity parameter determination for biomass particles of multiple size ranges in high heating rate devolatilization

This work presents a methodology that combines experimental measurements and Computational Fluid Dynamics (CFD) modeling to determine the global reaction kinetics of high heating rate biomass devolatilization. Three particle size ranges of woody biomass are analyzed: small (SF), medium (MF) and large (LF) fractions. Devolatilization mass loss is measured for each fraction in a laminar Drop-Tube Reactor (DTR) in nitrogen atmosphere, using two nominal reactor temperatures of 873 and 1173 K. Single First Order Reaction (SFOR) kinetics are determined by coupling an optimization routine with CFD models of the DTR. The global pre-exponential factors and activation energies for the SF, MF and LF particles are 5880 1/s and 42.7 kJ/mol, 48.1 1/s and 20.2 kJ/mol, and 102 1/s and 24.8 kJ/mol, respectively. These parameters are optimized for the isothermal heat transfer model available in CFD programs, and it is recommended that the specific heat capacity that was used in the optimization (1500 J/kgK) is used together with the parameters. Using the SF kinetics for small wood particles and either of the MF or LF kinetics for large particles, it is expected that more accurate devolatilization predictions can be obtained for the whole fuel size distribution in large scale CFD simulations.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Power Plant and Combustion Technology, Valmet Technologies Oy
Contributors: Niemelä, N. P., Tolvanen, H., Saarinen, T., Leppänen, A., Joronen, T.
Number of pages: 12
Pages: 676-687
Publication date: 1 Jun 2017
Peer-reviewed: Yes

Publication information

Journal: Energy
Volume: 128
ISSN (Print): 0360-5442
Ratings: 
  • Scopus rating (2017): CiteScore 8.1 SJR 1.99 SNIP 1.946
Original language: English
ASJC Scopus subject areas: Pollution, Energy(all)
Keywords: Biomass, Computational Fluid Dynamics (CFD), Devolatilization, High heating rate, Pyrolysis, Single First Order Reaction (SFOR)
Source: Scopus
Source ID: 85018474683

Research output: Contribution to journalArticleScientificpeer-review

Catalytic Activity of AuCu Clusters on MgO(100): Effect of Alloy Composition for CO Oxidation

Density functional simulations have been performed for Au7Cu23 and Au23Cu7 clusters on MgO(100) supports to probe their catalytic activity for CO oxidation. The adsorption of reactants, O2 and CO, and potential O2 dissociation have been investigated in detail by tuning the location of vacancies (F-center, V-center) in MgO(100). The total charge on Au7Cu23 and Au23Cu7 is negative on all supports, regardless of the presence of vacancies, but the effect is significantly amplified on the F-center. Au7Cu23/MgO(100) and Au23Cu7/MgO(100) with an F-center are the only systems to bind O2 more strongly than CO. In each case, O2 can be effectively activated upon adsorption and dissociated to 2 × O atoms. The different reaction paths based on the Langmuir-Hinshelwood (LH) and Eley-Rideal (ER) mechanisms for CO oxidation have been explored on the Au7Cu23 and Au23Cu7 clusters on F-centers, and the results are compared with the previous findings for Au15Cu15. Overall, the reaction barriers are small, but the changes in the Au:Cu ratio tune the reactant adsorption energies and sites considerably, showing also varying selectivity for CO and O2. The microkinetic model built on the basis of the above results shows a pronounced CO2 production rate at low temperature for the clusters on F-centers.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Research group: Materials and Molecular Modeling, COMP Centre of Excellence, Department of Applied Physics, Aalto University, Aalto University, Norwegian Univ. of Sci. and Technol.
Contributors: Ma, L., Laasonen, K., Akola, J.
Number of pages: 11
Pages: 10876-10886
Publication date: 25 May 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 121
Issue number: 20
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2017): CiteScore 7.9 SJR 2.135 SNIP 1.133
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Energy(all), Surfaces, Coatings and Films, Physical and Theoretical Chemistry
URLs: 
Source: Scopus
Source ID: 85020757142

Research output: Contribution to journalArticleScientificpeer-review

Geometric Structure and Chemical Ordering of Large AuCu Clusters: A Computational Study

Understanding the structure and composition of nanosized gold-copper (AuCu) clusters is crucial for designing an effective AuCu catalyst. Global optimization of AuCu clusters using atomistic force fields is a viable solution for clusters with at least a few nm sizes, because of its fast computation. Here we develop an atomistic many-body potential for AuCu on the basis of the second-moment approximation to the tight-binding model. We show that our potential is in good agreement with density-functional theory calculations, and use it to study the structure and chemical ordering of clusters of sizes up to ∼4 nm by means of global optimization searches. We show that the clusters present a surface enrichment in Au, while subsurface and central sites are enriched in Cu. Surface enrichment in Au and center enrichment in Cu are stronger in icosahedra. Surface Cu atoms prefer terrace sites on (111) facets. Both atomistic and DFT calculations show that L10 and L12 ordered phases are not favorable, even at their ideal compositions for these sizes, because of the tendency of Au to surface segregation. The stability range of icosahedral structures is wider in AuCu nanoalloys than in Au and Cu pure clusters.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, COMP Centre of Excellence, Department of Applied Physics, Aalto University, Aalto University, Università di Genova
Contributors: Goh, J., Akola, J., Ferrando, R.
Number of pages: 8
Pages: 10809-10816
Publication date: 25 May 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 121
Issue number: 20
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2017): CiteScore 7.9 SJR 2.135 SNIP 1.133
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Energy(all), Physical and Theoretical Chemistry, Surfaces, Coatings and Films
Source: Scopus
Source ID: 85016919329

Research output: Contribution to journalArticleScientificpeer-review

The effects of calcium and potassium on CO2 gasification of birch wood in a fluidized bed

Birch wood was leached of its naturally occurring ash forming elements and doped with three concentrations of calcium or potassium before being gasified in a laboratory bubbling fluidized bed reactor. The wood samples were pelletized and inserted into a fluidized bed reactor where they were first pyrolyzed with N2 and then gasified with CO2. In addition to tracking the gas concentration of the exit gas, char samples were taken from the fluidized bed and analyzed to study the char properties. The presence of potassium in the biomass was found to have a significant influence on the structure of the resulting char, however potassium did not have an observable catalytic effect on the overall gasification reaction rate with CO2 due to the formation of a unreactive coke layer on the char surface. In contrast, calcium did increase the char conversion rate and is likely the primary active catalyst in gasification of birch wood with CO2.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Industrial Bioengineering and Applied Organic Chemistry, Chemistry and Bioengineering, Research group: Power Plant and Combustion Technology, Universidad de Sevilla, Johan Gadolin Process Chemistry Centre, Abo Akademi University, Univ of Oulu
Contributors: Kramb, J., Gómez-Barea, A., DeMartini, N., Romar, H., Doddapaneni, T. R. K. C., Konttinen, J.
Number of pages: 10
Pages: 398-407
Publication date: 15 May 2017
Peer-reviewed: Yes

Publication information

Journal: Fuel
Volume: 196
ISSN (Print): 0016-2361
Ratings: 
  • Scopus rating (2017): CiteScore 8.8 SJR 1.891 SNIP 2.127
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Fuel Technology, Energy Engineering and Power Technology, Organic Chemistry
Keywords: Biomass, Catalysts, Char, Fluidized bed, Gasification
Source: Scopus
Source ID: 85012050856

Research output: Contribution to journalArticleScientificpeer-review

Photoinduced Electron Injection from Zinc Phthalocyanines into Zinc Oxide Nanorods: Aggregation Effects

Phthalocyanines (Pc) are well-known light-harvesting compounds. However, despite the tremendous efforts on phthalocyanine synthesis, the achieved energy conversion efficiencies for Pc-based dye-sensitized solar cells are moderate. To cast light on the factors reducing the conversion efficiency, we have undertaken a time-resolved spectroscopy study of the primary photoinduced reactions at a semiconductor-Pc interface. ZnO nanorods were chosen as a model semiconductor substrate with enhanced specific surface area. The use of a nanostructured oxide surface allows to extend the semiconductor-dye interface with a hole transporting layer (spiro-MeOTAD) in a controlled way, making the studied system closer to a solid-state dye-sensitized solar cell. Four zinc phthalocyanines are compared in this study. The compounds are equipped with bulky peripheral groups designed to reduce the self-aggregation of the Pcs. Almost no signs of aggregation can be observed from the absorption spectra of the Pcs assembled on a ZnO surface. Nevertheless, the time-resolved spectroscopy indicates that there are inter-Pc charge separation-recombination processes in the time frame of 1-100 ps. This may reduce the electron injection efficiency into the ZnO by more than 50%, pointing out to a remaining aggregation effect. Surprisingly, the electron injection time does not correlate with the length of the linker connecting the Pc to ZnO. A correlation between the electron injection time and the "bulkiness" of the peripheral groups was observed. This correlation is further discussed with the use of computational modeling of the Pc arrangements on the ZnO surface. (Figure Presented).

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Instituto Madrileño de Estudios Avanzados (IMDEA)-Nanociencia, Universidad Autónoma de Madrid, Mersin University, South-Ukrainian National Pedagogical University
Contributors: Virkki, K., Hakola, H., Urbani, M., Tejerina, L., Ince, M., Martínez-Díaz, M. V., Torres, T., Golovanova, V., Golovanov, V., Tkachenko, N. V.
Number of pages: 12
Pages: 9594-9605
Publication date: 4 May 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 121
Issue number: 17
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2017): CiteScore 7.9 SJR 2.135 SNIP 1.133
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Energy(all), Surfaces, Coatings and Films, Physical and Theoretical Chemistry
Source: Scopus
Source ID: 85020915273

Research output: Contribution to journalArticleScientificpeer-review

The IDE4L Project: Defining, Designing, and Demonstrating the Ideal Grid for All

The Purpose of the IDE4L project was to define, design, and demonstrate the ideal grid for all, with an active distribution network that integrates renewable energy sources (RESs) and new loads and guarantees the reliability of classical distribution networks. The active distribution network consists of the infrastructure of power delivery, active resources, and active network management (ANM) and combines passive infrastructure with active resources, ANM functionalities, and distribution automation information and communication technology infrastructure. Active distributed energy resources (DERs) include distributed generation (DG), demand, response, and storage. The concept of a commercial aggregator offering flexibility services is also integrated in an ANM.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Energy Engineering, Research area: Power engineering, Research group: Power systems, RWTH Aachen University, Unareti SpA, Schneider Electrics, Catalonia Institute for Energy Research (IREC), Danish Energy Association (Dansk Energi), Universidad Carlos III de Madrid, VTT Technical Research Centre of Finland
Contributors: Repo, S., Ponci, F., Della Giustina, D., Alvarez, A., Corchero Garcia, C., Al-Jassim, Z., Amaris, H., Kulmala, A.
Number of pages: 11
Pages: 41-51
Publication date: 1 May 2017
Peer-reviewed: Yes

Publication information

Journal: IEEE POWER AND ENERGY MAGAZINE
Volume: 15
Issue number: 3
ISSN (Print): 1540-7977
Ratings: 
  • Scopus rating (2017): CiteScore 4 SJR 0.942 SNIP 1.356
Original language: English
ASJC Scopus subject areas: Energy Engineering and Power Technology, Electrical and Electronic Engineering

Bibliographical note

EXT="Kulmala, Anna"

Source: Scopus
Source ID: 85018954673

Research output: Contribution to journalArticleScientificpeer-review

On the Efficient Calculation of the Periodic Steady-State Response of Grid-Connected Wind Parks - Part I

This paper presents a new power systems simulation environment suitable for the swift calculation of the periodic steady-state response of large power networks with large wind parks. In order to achieve the greatest computational efficiency and solution reliability, the wind generator model uses the state-of-the-art voltage-behind-reactance model of the induction generator; in this first part of the paper, the fixed-speed wind generator model is presented. The overall solving environment for the nonlinear system of differential equations representing the power system is the so-called Poincare map method. A rather useful feature to reduce further the calculation times is the availability of an equivalent wind farm model based on multiple wakes. The Poincare acceleration yields a vastly improved numerical solution compared to existing models of fixed-speed wind parks. The application of equivalent wind farm models yields a staggering reduction in the elapsed time to only 1.16% of the time demanded by the detailed model, while retaining a good approximation of the response of the wind farm. Full comparisons of the detailed and equivalent wind park models with PSCAD/EMTDC, are carried out and the agreement of the results is excellent. In this paper the emphasis is on harmonic generation.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Energy Engineering, Research area: Power engineering, Univ. Michoacana
Contributors: Garcia, N., Acha, E.
Number of pages: 10
Pages: 458-467
Publication date: 1 Apr 2017
Peer-reviewed: Yes

Publication information

Journal: IEEE Transactions on Sustainable Energy
Volume: 8
Issue number: 2
ISSN (Print): 1949-3029
Ratings: 
  • Scopus rating (2017): CiteScore 11.4 SJR 2.318 SNIP 2.496
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment
Keywords: Induction machine, periodic steady-state, Poincaré map method, voltage behind reactance model, wind farm
Source: Scopus
Source ID: 85027504357

Research output: Contribution to journalArticleScientificpeer-review

A New Miniaturized Sensor for Ultra-Fast On-Board Soot Concentration Measurements

In this article we present a design of a new miniaturized sensor with the capacity to measure exhaust particle concentrations on board vehicles and engines. The sensor is characterized by ultra-fast response time, high sensitivity, and a wide dynamic range. In addition, the physical dimensions of the sensor enable its placement along the exhaust line. The concentration response and temporal performance of a prototype sensor are discussed and characterized with aerosol laboratory test measurements. The sensor performance was also tested with actual engine exhaust in both chassis and engine dynamometer measurements. These measurements demonstrate that the sensor has the potential to meet and even exceed any requirements around the world in terms of on-board diagnostic (OBD) sensitivity and frequency of monitoring. Further to potential OBD applications, this has the capacity to be used as an engine and combustion diagnostics sensor, for example to detect misfiring, cylinder combustion variability, exhaust gas recirculation flowrate, etc.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Research area: Aerosol Physics, Research group: The Instrumentation, Emissions, and Atmospheric Aerosols Group, Research area: Optics, Aristotle University of Thessaloniki, Finnish Meteorological Institute, Pegasor Oy
Contributors: Rostedt, A., Ntziachristos, L. D., Simonen, P., Rönkkö, T., Samaras, Z. C., Hillamo, R., Janka, K., Keskinen, J.
Number of pages: 7
Publication date: 28 Mar 2017
Peer-reviewed: Yes

Publication information

Journal: SAE International Journal of Engines
Volume: 10
Issue number: 4
ISSN (Print): 1946-3936
Ratings: 
  • Scopus rating (2017): CiteScore 3.9 SJR 1.455 SNIP 1.636
Original language: English
ASJC Scopus subject areas: Automotive Engineering, Fuel Technology
Electronic versions: 
Source: Scopus
Source ID: 85018274264

Research output: Contribution to journalArticleScientificpeer-review

Output power variation of different PV array configurations during irradiance transitions caused by moving clouds

This paper presents a study of the output power variation of different photovoltaic (PV) array configurations during irradiance transitions caused by moving clouds. The study was based on velocity and other characteristics of roughly 27,000 irradiance transitions identified in measured irradiance data and conducted using a mathematical model of irradiance transitions and an experimentally verified simulation model of a PV module. The studied electrical PV array configurations were series-parallel, total-cross-tied and multi-string. The different PV array orientations and layouts (physical shapes) of the configurations were also studied. The average rate of change of the power of these studied PV array configurations during the irradiance transitions was around 3%/s and the maximum instantaneous rates of change of the power were around 75%/s. Half of the time during the studied transitions, the rate of change in the power was over 1.2%/s, and most of the time during the transitions, it exceeded typical PV power ramp rate limits set by grid operators. The average rate of change of PV array power decreased with an increasing maximum array dimension and it was observed to be the largest when the shorter dimension of the array was parallel to the dominant movement direction of the shadow edges. The results of this study are relevant especially in terms of PV array design, maximum power point tracking algorithm development and energy storage systems sizing.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Energy Engineering, Research area: Power engineering
Contributors: Lappalainen, K., Valkealahti, S.
Number of pages: 9
Pages: 902-910
Publication date: 15 Mar 2017
Peer-reviewed: Yes

Publication information

Journal: Applied Energy
Volume: 190
ISSN (Print): 0306-2619
Ratings: 
  • Scopus rating (2017): CiteScore 12.9 SJR 3.162 SNIP 2.79
Original language: English
ASJC Scopus subject areas: Civil and Structural Engineering, Energy(all)
Keywords: Irradiance transition, Partial shading, Photovoltaic power generation, Power variation, PV array
Source: Scopus
Source ID: 85009223592

Research output: Contribution to journalArticleScientificpeer-review

Effects of PV array layout, electrical configuration and geographic orientation on mismatch losses caused by moving clouds

The mismatch losses of photovoltaic (PV) systems are mainly caused by partial shading and the largest mismatch losses are caused by sharp shadows. However, in large scale PV plants majority of shading events is caused by moving clouds which lead to gentle irradiance transitions causing typically only minor irradiance differences between adjacent PV modules. Irradiance transitions caused by the edges of cloud shadows have an average length of almost 150 m meaning that even the largest PV power plants are widely affected by them. In addition of mismatch losses, these irradiance transitions can lead to failures in maximum power point tracking and cause significant fluctuations in the output power of PV systems. In this paper, the effects of PV array shape, electrical configuration and orientation on mismatch losses caused by moving clouds were studied based on apparent velocity and other measured characteristics of roughly 27,000 irradiance transitions. The study was conducted using a mathematical model and parametrisation method of irradiance transitions and an experimentally verified simulation model of a PV module based on the well-known one-diode model of a PV cell. The studied electrical PV array configurations were series-parallel, total-cross-tied and multi-string. The results of this study confirmed a prior conclusion, namely, that the mismatch losses decrease with decreasing PV string length. It was also found that the array orientation has a considerable effect on the mismatch losses of the studied array layouts. The mismatch losses were the smallest when the dominant direction of movement of the shadow edges was perpendicular to the PV strings. The differences in the mismatch losses between the studied electrical array configurations were very small. The results indicated that the mismatch losses caused by moving clouds have only a minor effect on the overall efficiency of PV arrays.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Energy Engineering, Research area: Power engineering
Contributors: Lappalainen, K., Valkealahti, S.
Number of pages: 8
Pages: 548-555
Publication date: 1 Mar 2017
Peer-reviewed: Yes

Publication information

Journal: Solar Energy
Volume: 144
ISSN (Print): 0038-092X
Ratings: 
  • Scopus rating (2017): CiteScore 6.9 SJR 1.615 SNIP 1.781
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Materials Science(all)
Keywords: Irradiance transition, Mismatch losses, Partial shading, Photovoltaic power generation
Source: Scopus
Source ID: 85011675458

Research output: Contribution to journalArticleScientificpeer-review

Determining maximum MPP-tracking sampling frequency for input-voltage-controlled PV-interfacing converter

A maximum-power-point tracking (MPPT) algorithm is essential in all controllers of solar power electronic converters due to the nonlinear current-voltage characteristics of a photovoltaic generator. One of the most widely utilized algorithms are perturbative MPPT techniques such as perturb and observe and incremental conductance methods due to their simple implementation with relatively good tracking performance. However, in order to optimize the performance of such algorithms, the design parameters - sampling frequency and perturbation step size - need to be designed in respect to interfaced power electronic converter. Recent studies have provided state-of-art MPP-tracking design rules for single and two-stage grid-connected PV systems. Unfortunately, the analysis of those studies does not provide analytical results for PV power transient response under feedback-controlled converters. This paper provides reduced-order transfer functions for the converters equipped with either I-type or PID-type controllers in order to approximate the maximum sampling or perturbation frequency for MPP-tracking algorithms. The analysis reveals the factors affecting the transient behavior similarly as in open-loop converter providing valuable tools for optimizing MPP-tracking perturbation frequency design.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering, Research area: Power engineering, Ariel University
Contributors: Kivimäki, J., Sitbon, M., Kolesnik, S., Kuperman, A., Suntio, T.
Publication date: 13 Feb 2017

Host publication information

Title of host publication: 8th Annual IEEE Energy Conversion Congress & Exposition (ECCE 2016)
Publisher: IEEE
ISBN (Electronic): 9781509007370
ASJC Scopus subject areas: Control and Systems Engineering, Electrical and Electronic Engineering, Energy Engineering and Power Technology, Control and Optimization
Source: Scopus
Source ID: 85015446286

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Cavitation erosion, slurry erosion and solid particle erosion performance of metal matrix composite (MMC) coatings sprayed with modern high velocity thermal spray processes

Thermally sprayed metal-matrix composite (MMC) coatings are widely used to protect components and surfaces against wear in various applications. Hard and wear resistant coatings increase the component lifetime and allow the refurbishment of the worn components. This produces significant savings and promotes ecological manufacturing. The current state-of-theart coatings are produced with high velocity oxygen-fuel (HVOF) spray processes, while modern high velocity air-fuel (HVAF) spray process has become increasingly available in production and research. The current study focuses on the performance of tungsten carbide (WC-10Co4Cr) and chromium carbide (Cr3C2-25NiCr) based MMC coatings sprayed with gaseous and liquid fuelled HVOF processes and a modern HVAF spray process. Two powder feedstock types, i.e. dense particles with fine carbides and porous particles with coarse carbides, were selected for both compositions. The results show significant improvements especially for WC-10Co4Cr coatings sprayed with HVAF when compared to HVOF sprayed coatings. In addition, Cr3C2-25NiCr coatings sprayed from the dense powder resulted in improved wear resistance compared to conventional feedstock powder.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Materials Science, Research group: Surface Engineering, Research group: Materials Characterization, VZÚ Plzeh, University of West Bohemia
Contributors: Matikainen, V., Rubio, S., Ojala, N., Koivuluoto, H., Schubert, J., Houdková, S., Vuoristo, P.
Number of pages: 3
Pages: 1161-1163
Publication date: 1 Jan 2017

Host publication information

Title of host publication: Materials Science and Technology Conference and Exhibition 2017, MS and T 2017 : October 8-12, 2017, Pittsburgh, Pennsylvania USA
Volume: 2
Publisher: Association for Iron and Steel Technology, AISTECH
ISBN (Electronic): 9781510850583
ASJC Scopus subject areas: Mechanics of Materials, Materials Science (miscellaneous), Energy Engineering and Power Technology
Keywords: Cavitation erosion, Coating, Metal matrix composite, Slurry erosion, Thermal spray
Source: Scopus
Source ID: 85047650405

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Chasing measurements for real-world emissions of city buses

General information

Publication status: Published
Organisations: Physics, Research area: Aerosol Physics, Research group: The Instrumentation, Emissions, and Atmospheric Aerosols Group, Atmospheric Composition Research, Finnish Meteorological Institute, Helsinki Region Environmental Services Authority (HSY), Department of Environmental Sciences, Helsinki University
Contributors: Järvinen, A., Karjalainen, P., Bloss, M., Potila, O., Simonen, P., Kuuluvainen, H., Timonen, H., Saarikoski, S., Niemi, J. V., Keskinen, J., Rönkkö, T.
Publication date: 2017
Peer-reviewed: Unknown
Event: Paper presented at European Aerosol Conference 2017, Zürich, Switzerland.
ASJC Scopus subject areas: Automotive Engineering, Pollution, Energy (miscellaneous)
Keywords: Exhaust emissions, bus emissions, Air quality

Research output: Other conference contributionPaper, poster or abstractScientific

Controlling emissions of natural gas engines

Different selective catalytic reduction (SCR) and oxidation catalyst systems were assessed to study the effects of these catalysts on the NOx, the hydrocarbon and the particle emissions from natural gas engines. High NOx reductions were observed at low ammonia slips. A separate oxidation catalyst was used downstream of the SCR. The NOx reduction efficiency was found to depend on the exhaust gas temperature. The efficiency of a catalyst reactor to remove hydrocarbons was found to depend on the hydrocarbon species, the exhaust temperature as well as the exhaust flow. The total measured PM mass was lower downstream of the catalyst than in the engine exhaust at all temperatures studied. Catalyst systems were found to have significant effects on particulate emissions.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Physics, Research area: Aerosol Physics, Research group: The Instrumentation, Emissions, and Atmospheric Aerosols Group, VTT Technical Research Centre of Finland, Finnish Meteorological Institute, Dinex Ecocat, Wärtsilä Finland Oy
Contributors: Lehtoranta, K., Murtonen, T., Vesala, H., Koponen, P., Alanen, J., Kuittinen, N., Simonen, P., Rönkkö, T., Saarikoski, S., Timonen, H., Maunula, T., Kallinen, K., Korhonen, S.
Publication date: 2017

Host publication information

Title of host publication: Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA2017
Publisher: Air and Waste Management Association
ASJC Scopus subject areas: Environmental Science(all), Energy(all)
Source: Scopus
Source ID: 85039150198

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Cultivation of Scenedesmus acuminatus in different liquid digestates from anaerobic digestion of pulp and paper industry biosludge

Different undiluted liquid digestates from mesophilic and thermophilic anaerobic digesters of pulp and paper industry biosludge with and without thermal pretreatment were characterized and utilized for cultivating Scenedesmus acuminatus. Higher S. acuminatus biomass yields were obtained in thermophilic digestates (without and with pretreatment prior to anaerobic digestion (AD): 10.2 ± 2.2 and 10.8 ± 1.2 g L−1, respectively) than in pretreated mesophilic digestates (7.8 ± 0.3 g L−1), likely due to differences in concentration of sulfate, iron, and/or other minor nutrients. S. acuminatus removed over 97.4% of ammonium and 99.9% of phosphate and sulfate from the digestates. Color (74–80%) and soluble COD (29–39%) of the digestates were partially removed. Different AD processes resulted in different methane yields (18–126 L CH4 kg−1 VS), digestate compositions, and microalgal yields. These findings emphasize the importance of optimizing each processing step in wood-based biorefineries and provide information for pulp and paper industry development for enhancing value generation.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Tao, R., Lakaniemi, A., Rintala, J. A.
Number of pages: 8
Pages: 706-713
Publication date: 2017
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 245
Issue number: A
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2017): CiteScore 10 SJR 2.029 SNIP 1.84
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Renewable Energy, Sustainability and the Environment, Waste Management and Disposal
Keywords: Digestate characteristics, Microalgal growth, Nutrient recovery, Pulp and paper industry, Wastewater treatment
Source: Scopus
Source ID: 85029373417

Research output: Contribution to journalArticleScientificpeer-review

Design of a 25 MWe Solar Thermal Power Plant in Iran with Using Parabolic Trough Collectors and a Two-Tank Molten Salt Storage System

Nowadays, parabolic trough solar thermal plants are prevalent around the world. In different areas concerning the amount of solar radiation, their standard size is approximately between 20 and 100 MWe. Certainly, the right size of the solar field is the first selection with regard to nominal electrical power. A vast area will be economically unreasonable whereas a small area will mainly cause the power plant to operate at the part-load condition. This paper presents an economic modeling of a solar parabolic trough plant, operating at 25 MWe in Yazd, Iran. The varying types of collector dimensions have been investigated; then, by selecting autumnal equinox (22 September) at 12:00 PM as the design point, thermal performance of the solar power plant has been featured annually, in all conditions. The total operating time of the power plant is about 1726 hours (1248 hours in full-load condition). In the end, the effect of thermal storage tanks has been analyzed to save extra solar heat and use it at nights in hot months. By implementing a storage system, the total operating time will be increased to 3169 hours (2785 in full-load condition). Moreover, 7974 GJ useful thermal energy can be obtained from the solar field and storage system.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Automation and Hydraulic Engineering, University of Guilan
Contributors: Kordmahaleh, A. A., Naghashzadegan, M., Javaherdeh, K., Khoshgoftar, M.
Publication date: 2017
Peer-reviewed: Yes

Publication information

Journal: International Journal of Photoenergy
Volume: 2017
Article number: 4210184
ISSN (Print): 1110-662X
Ratings: 
  • Scopus rating (2017): CiteScore 2.8 SJR 0.341 SNIP 0.605
Original language: English
ASJC Scopus subject areas: Chemistry(all), Atomic and Molecular Physics, and Optics, Renewable Energy, Sustainability and the Environment, Materials Science(all)
Electronic versions: 

Bibliographical note

INT=aut,"Kordmahaleh, Aidin Alinezhad"

Source: Scopus
Source ID: 85038904387

Research output: Contribution to journalArticleScientificpeer-review

Numerical simulation and measurements of drying of Finnish concrete grades

A numerical simulation model is presented to predict drying of concrete slabs of certain Finnish concrete grades. The coupled equations of heat and moisture transport in porous materials including the hydration phenomenon are incorporated in the model. The simulation model and its parameters were calibrated according to long-term measurements that were performed in a laboratory for test pieces of different concrete grades. As the material properties for quantities governing moisture transport were insufficient, parameters of the functions describing the material properties were fitted to the experimental data by employing the optimization analysis coupled to the simulation. A reasonable agreement was found and the unknown material parameters were solved, the values of which can be used in further simulations of real concrete structures.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Vahanen Building Physics Ltd, Comsol Oy
Contributors: Sekki, P., Karvinen, T.
Number of pages: 6
Pages: 729-734
Publication date: 2017
Peer-reviewed: Yes

Publication information

Journal: Energy Procedia
Volume: 132
Issue number: October
ISSN (Print): 1876-6102
Ratings: 
  • Scopus rating (2017): CiteScore 1.7 SJR 0.495 SNIP 0.823
Original language: English
ASJC Scopus subject areas: Energy(all)
Keywords: Drying of concrete, early-age concrete, moisture diffusivity, numerical simulation, self-desiccation

Bibliographical note

EXT="Karvinen, Timo"

Source: Scopus
Source ID: 85033375327

Research output: Contribution to journalArticleScientificpeer-review

Photophysical properties of porphyrin dimer-single-walled carbon nanotube linked systems

Porphyrin dimers were covalently grafted onto electron-accepting single-walled carbon nanotube (SWNT) sidewalls by direct aryl radical addition reaction with an m-or p-phenylene linker with the help of p-p interaction between the porphyrins. A splitting of the porphyrin Soret band and DFT calculations supported the selective formation of the porphyrin dimers on the sidewall of SWNTs. Photoexcitation of the porphyrin dimers on the SWNT resulted in the formation of the exciplex state, which directly decayed to the ground state without yielding the complete charge-separated state. Lifetimes of the porphyrin dimer-SWNT exciplex were longer than that of a porphyrin monomer-SWNT exciplex due to the stabilization by p-electron interaction over two porphyrin rings. In addition, the weaker electronic coupling through the meta-linkage than the para-one may be responsible for the exciplex lifetime of the porphyrin dimer-SWNT with the m-phenylene linker (49 ps) longer than that with the p-phenylene one (24 ps). The results obtained here provide the basic information on the effect of the donor dimerization on the photodynamic behavior of the exciplex state in donor-acceptor linked systems. [Figure presented]

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Kyoto Women's University
Contributors: Baek, J., Umeyama, T., Mizuno, S., Tkachenko, N. V., Imahori, H.
Publication date: 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 121
Issue number: 39
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2017): CiteScore 7.9 SJR 2.135 SNIP 1.133
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Energy(all), Physical and Theoretical Chemistry, Surfaces, Coatings and Films
Source: Scopus
Source ID: 85032629899

Research output: Contribution to journalArticleScientificpeer-review

Rakennusfysiikka 2017. Uusimmat tutkimustulokset ja hyvät käytännön ratkaisut: 24.-26.10.2017, Tampere. Seminaarijulkaisu 5 - Osa 1

General information

Publication status: Published
MoE publication type: D6 Edited professional books
Organisations: Civil Engineering, Research group: Building Physics
Contributors: Vinha, J. (ed.), Kivioja, H. (ed.)
Number of pages: 370
Publication date: 2017

Publication information

Place of publication: Tampere
Publisher: Tampereen teknillinen yliopisto, Rakennustekniikka, Rakennusfysiikka
Volume: 1
ISBN (Print): 978-952-15-4022-6
Original language: Finnish
ASJC Scopus subject areas: Engineering(all), Energy(all), Materials Science(all)
Electronic versions: 

Research output: Book/ReportAnthologyProfessional

Rakennusfysiikka 2017. Uusimmat tutkimustulokset ja hyvät käytännön ratkaisut: 24.-26.10.2017, Tampere. Seminaarijulkaisu 5 - Osa 2

General information

Publication status: Published
MoE publication type: D6 Edited professional books
Organisations: Civil Engineering, Research group: Building Physics
Contributors: Vinha, J. (ed.), Kivioja, H. (ed.)
Number of pages: 256
Publication date: 2017

Publication information

Place of publication: Tampere
Publisher: Tampereen teknillinen yliopisto, Rakennustekniikka, Rakennusfysiikka
Volume: 2
ISBN (Print): 978-952-15-4023-3
Original language: Finnish
ASJC Scopus subject areas: Engineering(all), Energy(all), Materials Science(all)
Electronic versions: 

Research output: Book/ReportAnthologyProfessional

Rakennusten rakennusfysikaalisen suunnittelun ja toteutuksen periaatteet

General information

Publication status: Published
MoE publication type: D2 Article in professional manuals or guides or professional information systems or text book material
Organisations: Civil Engineering, Research group: Building Physics
Contributors: Vinha, J.
Number of pages: 60
Pages: 117-176
Publication date: 2017

Host publication information

Title of host publication: Rakentajain kalenteri 2018
Publisher: Rakennustieto Oy
Editors: Koskenvesa, A., Lyytinen, J., Laine, S.

Publication series

Name: Rakentajain kalenteri
Volume: 102
ISSN (Print): 0355-550X
ASJC Scopus subject areas: Engineering(all), Energy(all)

Research output: Chapter in Book/Report/Conference proceedingChapterProfessional

Release of Potassium during Devolatilization of Spruce Bark

The spruce bark with different particle sizes were devolatilized under various final temperatures and heating rates. The char yield and potassium release from the spruce bark at studied conditions were quantified. Lower char yields realized from the smaller fuel particles at high temperature and heating rate. It is mainly attributed to shorter residence time of volatiles in the fuel/char particles and less intensive secondary reaction of volatiles consequently. The devolatilization temperature has the most significant effects on alkali release from the studied sprue bark. At 600°C, less than 5% of alkali released from the both small and large particles regardless of heating rate. However, at 850°C, release of potassium from the small sprue bark particles sharply increased from 2.63% and 4.71% to 12.87% and 17.89%, as they were heated under heating rate of 50 K/min and 500 K/min, respectively. Large fraction of alkali released from studied fuel particles as they were devolatilized under a high heating rate. Additionally, more potassium release from small particles (125 <d<180 μm) then the larger ones (500 <d<600 μm) and this tendency increased with devolatilization temperature. In brief, intensive devolatilization conditions may limit secondary reactions of potassium containing compounds in the volatiles and thereby formation of more stable phases. The results obtained in the present work are of importance for understanding of potassium release during thermal conversion of spruce bark and proposing measures for mitigating potassium related operational problems.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, SINTEF Energy Research, Andritz AG
Contributors: Wang, L., Moilanen, A., Lehtinen, J., Konttinen, J., Matas, B. G.
Number of pages: 7
Pages: 1295-1301
Publication date: 2017
Peer-reviewed: Yes

Publication information

Journal: Energy Procedia
Volume: 105
ISSN (Print): 1876-6102
Ratings: 
  • Scopus rating (2017): CiteScore 1.7 SJR 0.495 SNIP 0.823
Original language: English
ASJC Scopus subject areas: Energy(all)
Keywords: char, devolatilization, ICP-OES, potassium, SEM-EDX, Spruce bark
Source: Scopus
Source ID: 85020700355

Research output: Contribution to journalArticleScientificpeer-review

Particle emissions characterization from a medium-speed marine diesel engine with two fuels at different sampling conditions

Particle emission characteristics for a medium-speed four-stroke marine diesel engine were studied using a variety of sampling systems. Measurements were conducted at 25% and 75% load employing a heavy fuel oil (HFO) and a lighter marine distillate oil. The measurements, especially with HFO, revealed that marine exhaust particles mostly consist of nanometer sized ash particles on which heavy volatile species condense during exhaust dilution and cooling. The soot mode number concentration was low with both fuels tested, in particular when HFO was used. Total particle number emissions ranged in the order of 5.2–6.9 × 1015 per kg of fuel and formed a monomodal size distribution when a porous tube diluter combined with an ageing chamber and operating at low dilution ratio was used for sampling. The levels and size distributions obtained in the lab using a porous tube diluter were similar to the ones reported in the literature studying ship plumes following atmospheric dilution. Lab measurements with ejector-type diluters mostly led to bi-modal distributions that did not well resemble atmospheric size distributions. Moreover, the nucleation mode formed with the ejector diluters was variable in size and concentration. When used with dilution air at ambient temperature, ejector diluters were inappropriate for primary dilution due to clogging.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Aerosol Physics Laboratory, VTT Technical Research Centre of Finland, Finnish Meteorological Institute
Contributors: Ntziachristos, L., Saukko, E., Lehtoranta, K., Rönkkö, T., Timonen, H., Simonen, P., Karjalainen, P., Keskinen, J.
Number of pages: 10
Pages: 456-465
Publication date: 15 Dec 2016
Peer-reviewed: Yes

Publication information

Journal: Fuel
Volume: 186
ISSN (Print): 0016-2361
Ratings: 
  • Scopus rating (2016): CiteScore 7.8 SJR 1.736 SNIP 2.206
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Fuel Technology, Energy Engineering and Power Technology, Organic Chemistry
Keywords: Heavy fuel oil, Light fuel oil, Marine emissions, Particle emissions, Soot particles
Source: Scopus
Source ID: 84984817885

Research output: Contribution to journalArticleScientificpeer-review

Thermal Modification of ALD Grown Titanium Oxide Ultra Thin Film for Photoanode Applications

General information

Publication status: Published
Organisations: Optoelectronics Research Centre, Research group: Surface Science
Contributors: Hannula, M. K., Lahtonen, K. T., Isotalo, T. J., Saari, J. S., Valden, M. O.
Publication date: 15 Dec 2016
Peer-reviewed: Unknown
Event: Paper presented at Symposium on Future Prospects for Photonics, Tampere, Finland.
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Surfaces, Coatings and Films, Surfaces and Interfaces, Atomic and Molecular Physics, and Optics
Keywords: Titanium dioxide, titanium silicide, Atomic layer deposition (ALD), photoemission electron microscopy, PEEM, hydrogen energy

Research output: Other conference contributionPaper, poster or abstractScientific

Optimal control of pump rotational speed in filling and emptying a reservoir: minimum energy consumption with fixed time

An effective way to save energy in pumping systems with low static head is to control the pump’s rotational speed with a variable-speed drive (VSD), which allows changing of the rotational speed when necessary. VSDs can be utilized to control batch transfer systems, for example, in filling or emptying a tank or a reservoir. In the literature, such processes have been optimized only with respect to energy consumption, but the time limit has been ignored. This means that pumping time can be very long. Our paper deals with this optimization problem and considers both pumping time and energy demand, which are often conflicting criteria. We derived a general optimal control law for rotational speed, which can easily be implemented in existing VSDs in the market. Minimum energy and minimum time schemes are special cases of this general new scheme. A constant flow rate scheme, suggested in the literature, is verified to give an optimum solution if the efficiency of the pump remains constant during operation. In addition to energy consumption, rotational speed control can have a favorable effect on the pump’s lifetime, as pointed out in the paper.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Mechanical Engineering and Industrial Systems, FS Dynamics Finland Oy Ab
Contributors: Lindstedt, M., Karvinen, R.
Number of pages: 14
Pages: 1461–1474
Publication date: Dec 2016
Peer-reviewed: Yes
Early online date: 12 Mar 2016

Publication information

Journal: Energy Efficiency
Volume: 9
Issue number: 6
ISSN (Print): 1570-646X
Ratings: 
  • Scopus rating (2016): CiteScore 2.5 SJR 0.744 SNIP 0.871
Original language: English
ASJC Scopus subject areas: Energy(all)
Keywords: Energy efficiency, Process control, Pumps, Variable-speed drives

Bibliographical note

EXT="Lindstedt, Matti"

Source: Scopus
Source ID: 84960430781

Research output: Contribution to journalArticleScientificpeer-review

Apparent velocity of shadow edges caused by moving clouds

Even the largest photovoltaic (PV) power plants are widely affected by overpassing cloud shadows which have several harmful effects on the operation of PV systems. Irradiance transitions caused by edges of cloud shadows can be very steep and large and might lead to situations where the grid inverter is not able to follow the global maximum power point. Further, partial shading of PV systems causes mismatch losses and fast fluctuations of the power fed to the electric grid can cause power balance and quality problems. In this paper, a method to determine apparent shadow edge velocity from measured data of three irradiance sensors is presented. A total of around 43,000 irradiance transitions were first identified in 15 months of data measured with one of the sensors around midsummer in 2011–2014. Out of those about 27,000 transitions were identified by all the three irradiance sensors and their apparent shadow edge velocity, length, etc. were analysed. The apparent shadow edge speed varies greatly with an average value of around 9 m/s. The lengths of irradiance transitions caused by edges of moving clouds are typically around 100 m, which is large enough to affect the operation of PV power plants of all sizes.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Electrical Engineering, Research area: Power engineering
Contributors: Lappalainen, K., Valkealahti, S.
Number of pages: 6
Pages: 47-52
Publication date: 15 Nov 2016
Peer-reviewed: Yes

Publication information

Journal: Solar Energy
Volume: 138
ISSN (Print): 0038-092X
Ratings: 
  • Scopus rating (2016): CiteScore 6.4 SJR 1.504 SNIP 1.752
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Materials Science(all)
Keywords: Apparent shadow edge velocity, Irradiance transition, Partial shading, Solar radiation
Source: Scopus
Source ID: 84987875834

Research output: Contribution to journalArticleScientificpeer-review

Multicriteria selection in concept design of a divertor remote maintenance port in the EU DEMO reactor using an AHP participative approach

The work behind this paper took place in the Eurofusion remote maintenance system project (WPRM) for the EU Demonstration Fusion Power Reactor (DEMO). Following ITER, the aim of DEMO is to demonstrate the capability of generating several hundreds of MW of net electricity by 2050. The main objective of this paper was the study of the most efficient design of the maintenance port for replacing the divertor cassettes in a Remote Handling (RH) point of view. In DEMO overall design, one important consideration is the availability and short down time operations. The inclination of the divertor port has a very important impact on all the RH tasks such as the design of the divertor mover, the divertor locking systems and the end effectors. The current reference scenario of the EU DEMO foresees a 45° inclined port for the remote maintenance (RM) of the divertor in the lower part of the reactor. Nevertheless, in the optic of the systems engineering (SE) approach, in early concept design phase, all possible configurations shall be taken into account. Even the solutions which seem not feasible at all need to be investigated, because they could lead to new and innovative engineering proposals. The different solutions were compared using an approach based on the Analytic Hierarchy Process (AHP). The technique is a multi-criteria decision making approach in which the factors that are important in making a decision are arranged in a hierarchic structure. The results of these studies show how the application of the AHP improved and focused the selection on the concept which is closer to the requirements arose from technical meetings with the experts of the RH field.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Intelligent Hydraulics and Automation, Research group: Fluid power automation in mobile machines, ENEA/CREATE/Università Degli Studi Napoli Federico II, VTT Technical Research Centre of Finland, ENEA Brasimone
Contributors: Carfora, D., Gironimo, G. D., Esposito, G., Huhtala, K., Määttä, T., Mäkinen, H., Miccichè, G., Mozzillo, R.
Number of pages: 8
Pages: 324-331
Publication date: 15 Nov 2016
Peer-reviewed: Yes

Publication information

Journal: Fusion Engineering and Design
Volume: 112
ISSN (Print): 0920-3796
Ratings: 
  • Scopus rating (2016): CiteScore 2.3 SJR 0.579 SNIP 1.022
Original language: English
ASJC Scopus subject areas: Civil and Structural Engineering, Materials Science(all), Nuclear Energy and Engineering, Mechanical Engineering
Keywords: AHP, Concept design, DEMO, Remote handling, Systems engineering
Source: Scopus
Source ID: 84994060921

Research output: Contribution to journalArticleScientificpeer-review

A Unified Modeling Approach of Multi-Terminal VSC-HVDC Links for Dynamic Simulations of Large-Scale Power Systems

This paper introduces a new and general frame-of-reference for dynamic solutions of multi-terminal VSC-HVDC systems using the Newton-Raphson method. Three VSC dynamic models are derived to conform to each pairing AC sub-network-the slack converter whose aim is to control its DC voltage, the scheduled-power converter which injects a scheduled amount of power and the passive converter which is connected to an AC network with no frequency control equipment. Each VSC unit makes provisions for the phase reactor, AC filter, DC capacitor, DC smoothing inductor and LTC transformer. The VSC itself is a positive-sequence lumped-type model whose core elements are a phase-shifting transformer and an equivalent shunt susceptance which account for the phase-shifting and scaling nature of the PWM control. In turn, the DC side of each pairing VSC unit is linked to a DC system of an arbitrary configuration. All this enables the assembly of any number of VSCs, giving rise to a comprehensive formulation of multi-terminal VSC-HVDC systems. The prowess of the proposed multi-terminal dynamic model is demonstrated by carrying out a comparison against the widely-used EMT-type package Simulink, using a three terminal VSC-HVDC system, with very good results. Furthermore, a six-terminal VSC-HVDC system forming a DC ring is used to show the applicability of the proposed unified approach when solving multi-terminal VSC-HVDC links for system-wide dynamic studies.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Electrical Engineering, Research area: Power engineering, National Autonomous University of Mexico
Contributors: Castro, L. M., Acha, E.
Number of pages: 10
Pages: 5051-5060
Publication date: 1 Nov 2016
Peer-reviewed: Yes

Publication information

Journal: IEEE Transactions on Power Systems
Volume: 31
Issue number: 6
ISSN (Print): 0885-8950
Ratings: 
  • Scopus rating (2016): CiteScore 12.1 SJR 3.368 SNIP 3.597
Original language: English
ASJC Scopus subject areas: Energy Engineering and Power Technology, Electrical and Electronic Engineering
Keywords: Multi-terminal VSC-HVDC systems, Newton-Raphson method, VSC-HVDC dynamic modeling
Source: Scopus
Source ID: 84959422989

Research output: Contribution to journalArticleScientificpeer-review

Analysis of shading periods caused by moving clouds

Fast variability of solar radiation is the main cause of fluctuating photovoltaic power production. Shadows caused by moving clouds are the main reason of such variability. Irradiance transitions caused by edges of cloud shadows can be very steep and large and might lead to failures in maximum power point tracking causing extra losses. Further, fast fluctuations of the power fed to the electric grid can cause power balance and quality problems for the grid.This paper presents a method to identify shading periods caused by moving clouds in measured irradiance data. A total of around 12,000 shading periods were identified in a measured data of 15 months around midsummer in 2011-2014 and their shading strength, duration, time of occurrence etc. were analysed. It was found that the duration of shading periods varies a lot from about four seconds up to almost 1.5 h with an average duration of around 60 s. Furthermore, the Linear Cloud Edge method was used to determine the velocity of shadows and their speed, direction of movement, length etc. were analysed. The determination of velocity was conducted by two different ways based directly on measured irradiance values and on the curve fits of a mathematical model of irradiance transitions. The use of curve fits mitigates the effects of irregularities present on shadow edges. The speed of shadows varies greatly with an average value of around 13 m/s.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Electrical Engineering, Research area: Power engineering
Contributors: Lappalainen, K., Valkealahti, S.
Number of pages: 9
Pages: 188-196
Publication date: 1 Oct 2016
Peer-reviewed: Yes

Publication information

Journal: Solar Energy
Volume: 135
ISSN (Print): 0038-092X
Ratings: 
  • Scopus rating (2016): CiteScore 6.4 SJR 1.504 SNIP 1.752
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Materials Science(all)
Keywords: Partial shading, Shading period, Shadow velocity, Solar radiation
Source: Scopus
Source ID: 84971664094

Research output: Contribution to journalArticleScientificpeer-review

Elimination of arsenic-containing emissions from gasification of chromated copper arsenate wood

The behavior of arsenic in chromated copper arsenate containing wood during gasification was modeled using thermodynamic equilibrium calculations. The results of the model were validated using bench-scale gasification tests. It is shown that over 99.6% of arsenic can be removed from the product gas by a hot filter when the gas is cooled below the predicted condensation temperature.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Industrial Bioengineering and Applied Organic Chemistry, Energy Technology and Thermal Process Chemistry, Gasification Technologies Inc., Gas Technology Institute
Contributors: Kramb, J., Konttinen, J., Backman, R., Salo, K., Roberts, M.
Number of pages: 6
Pages: 319-324
Publication date: 1 Oct 2016
Peer-reviewed: Yes

Publication information

Journal: Fuel
Volume: 181
ISSN (Print): 0016-2361
Ratings: 
  • Scopus rating (2016): CiteScore 7.8 SJR 1.736 SNIP 2.206
Original language: English
ASJC Scopus subject areas: Fuel Technology, Energy Engineering and Power Technology, Chemical Engineering(all), Organic Chemistry
Keywords: Arsenic, CCA wood, Equilibrium modeling, Gasification
Source: Scopus
Source ID: 84965081806

Research output: Contribution to journalArticleScientificpeer-review

Exposure to biological and chemical agents at biomass power plants

The increasing use and production of bioenergy means that the number of employees working in this area will inevitably grow, making it ever more important to know the health and safety issues involved in the biomass supply chain. Our aim was to determine the exposure of employees to biological and chemical agents during various work tasks at different biomass-fuelled power plants in Finland. The study included technical surveys on biomass operations and occupational measurements at three CHP plants. Workers’ main health risks were bacteria and fungi, which were easily spread to the air during heavy biomass processes. The exposure levels of actinobacteria, bacterial endotoxins and fungi were high, especially during the unloading of peat and wood chips. In addition, workers were exposed to mechanical irritation caused by organic dust, and chemical irritation caused by volatile organic compounds and components of diesel exhausts. Multiple exposures to these agents may simultaneously have synergistic health effects on workers’ lower and upper respiratory tracts. During operations, workers were also exposed to endotoxins, actinobacteria and fungi, especially during the cleaning and handling of wood chips in silos and while working near screens or crushers. The measured concentrations exceeded the limit values proposed for these agents. The highest concentration of volatile organic compounds was found near conveyors. On the basis of these measurements, we suggested best practices for the power plants. The levels of biological agents in outdoor measurements reflected only low spreading of contaminants from power plants to the environment.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Electronics and Communications Engineering, Research group: Environmental Health, Tyoterveyslaitos, VTT Technical Research Centre of Finland, Finnish Institute of Occupational Health, University of Eastern Finland
Contributors: Laitinen, S., Laitinen, J., Fagernäs, L., Korpijärvi, K., Korpinen, L., Ojanen, K., Aatamila, M., Jumpponen, M., Koponen, H., Jokiniemi, J.
Number of pages: 9
Pages: 78-86
Publication date: 1 Oct 2016
Peer-reviewed: Yes

Publication information

Journal: Biomass & Bioenergy
Volume: 93
ISSN (Print): 0961-9534
Ratings: 
  • Scopus rating (2016): CiteScore 6.4 SJR 1.198 SNIP 1.411
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Forestry, Renewable Energy, Sustainability and the Environment, Waste Management and Disposal
Keywords: Bioenergy, Biological agents, Chemical compounds, Exposure, Occupational hygiene, Power plants
Source: Scopus
Source ID: 84977492787

Research output: Contribution to journalArticleScientificpeer-review

Power flow solutions of AC/DC micro-grid structures

This paper presents a new and general frame-of-reference for the unified, power flow solution of AC and DC micro-grids using the Newton-Raphson method, where the quadratic convergence towards the solution is preserved. The cornerstone of this modeling development in power flow theory is the so-called multi-terminal VSC-HVDC system. In this frame-of-reference, an AC micro-grid of arbitrary configuration is connected to the high-voltage side of the LTC transformer of a VSC station. In turn, the DC side of each VSC is linked to a DC system of arbitrary configuration. Any number of AC micro-grids may exist and the DC system may contain single load or generation points such as a PV installation. Each VSC model takes into account, in aggregated form, the phase-shifting and scaling nature of the PWM control. It also accounts for the VSC current design limits, PWM limits within the linear range, switching losses and ohmic losses.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Department of Electrical Engineering, Research area: Power engineering, National Autonomous University of Mexico
Contributors: Acha, E., Rubbrecht, T., Castro, L. M.
Publication date: 10 Aug 2016

Host publication information

Title of host publication: 19th Power Systems Computation Conference, PSCC 2016
Publisher: IEEE
ISBN (Print): 978-1-4673-8151-2
ASJC Scopus subject areas: Computer Networks and Communications, Energy Engineering and Power Technology
Keywords: Micro-grids, multi-terminal HVDC systems, Newton-Raphson method, power flows, VSC modeling
Source: Scopus
Source ID: 84986550301

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Comparison of photovoltaic and wind generators as dynamic input sources to power processing interfaces

The paper reveals that while the equivalent circuit, representing the load side reflected low-frequency dynamics of a wind turbine generator, is similar to the electrical equivalent circuit of a photovoltaic generator, their dynamic resistances possess different behavior. While the incremental conductance of a photovoltaic generator does not change sign with terminal voltage variations, zero-crossing dynamic conductance characterizes wind turbine generator. The findings points out the complications arising during interfacing a wind turbine generator by different power processing interfaces.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Department of Electrical Engineering, Research area: Power engineering, Ariel University Center of Samaria
Contributors: Kolesnik, S., Sitbon, M., Agranovich, G., Kuperman, A., Suntio, T.
Publication date: 25 Jul 2016

Host publication information

Title of host publication: 2016 2nd International Conference on Intelligent Energy and Power Systems, IEPS 2016 - Conference Proceedings
Publisher: IEEE
ISBN (Electronic): 9781509017690
ASJC Scopus subject areas: Energy Engineering and Power Technology, Renewable Energy, Sustainability and the Environment, Control and Systems Engineering, Electrical and Electronic Engineering
Keywords: dynamic resistance, equivalent electrical circuit, Photovoltaic generator, wind turbine
Source: Scopus
Source ID: 84983341165

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Cost-causation based approach in forming power-based distribution network tariff for small customers

This paper discusses the development of electricity distribution network tariffs. In the paper, the present state of distribution network tariffs of small customers is discussed together with key future challenges of the distribution network business. As a potential solution to these challenges, power-based tariffs of the small customers are discussed and preliminary results of a case study are presented where tariffs are formed by applying data of one Finnish Distribution System Operator (DSO).

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Department of Electrical Engineering, Research area: Power engineering, Helen Ltd.
Contributors: Lummi, K., Rautiainen, A., Järventausta, P., Heine, P., Lehtinen, J., Hyvärinen, M.
Publication date: 25 Jul 2016

Host publication information

Title of host publication: 2016 13th International Conference on the European Energy Market, EEM 2016
Publisher: IEEE COMPUTER SOCIETY PRESS
ISBN (Electronic): 9781509012978
ASJC Scopus subject areas: Marketing, Energy Engineering and Power Technology, Fuel Technology
Keywords: Electricity distribution business, electricity distribution network tariff, power-based distribution tariff
Source: Scopus
Source ID: 84983343584

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Network impacts of distribution power tariff schemes with active customers

In this paper we study the network impacts of power based distribution tariff which has been widely discussed in Finland as a future electricity distribution tariff also for small customers. The abundance of smart meters in Finland has enabled new forms of electricity pricing schemes, most notably hourly based energy pricing utilized by many Finnish retailers presently. However, the distribution pricing schemes are currently virtually same as during pre-deregulation and before the automatic meter reading (AMR) infrastructure. The paper presents the network impacts (voltage and current violations) of proposed tariff scheme based on load flow simulation of large-scale real-life distribution network from Finland. Simulations include the impact of both the retail and the distribution tariffs. Customers having large enough energy consumption (electric heating customers) are simulated to have a home automation for energy management. The results show that customer energy optimization can cause significant investment needs to the network and that power based distribution tariff can mitigate these issues.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Department of Electrical Engineering, Research area: Power engineering
Contributors: Supponen, A., Rautiainen, A., Lummi, K., Järventausta, P., Repo, S.
Publication date: 25 Jul 2016

Host publication information

Title of host publication: 2016 13th International Conference on the European Energy Market, EEM 2016
Publisher: IEEE COMPUTER SOCIETY PRESS
ISBN (Electronic): 9781509012978
ASJC Scopus subject areas: Marketing, Energy Engineering and Power Technology, Fuel Technology
Keywords: Electricity Distribution Pricing, Energy management/optimization, Network Impacts, Power Tariff

Bibliographical note

AUX=DEE,"Supponen, Antti"

Source: Scopus
Source ID: 84983371980

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

The role of residential prosumers initiating the energy innovation ecosystem to future flexible energy system

This paper explores prosumer role in Smart Grid innovation ecosystem as part of the energy market transition from traditional energy system to future flexible energy ecosystem based on renewable energy sources. This transition is facilitated by international agendas and government actions to slow down climate change globally and technological advancements in multiple areas like consumer electronics (e.g. smart appliances) and Information and Communication Technologies (ICT). These developments render industries to converge and traditional structures are changing. Despite the technology developments and top-down policy push, the Smart Grid innovation ecosystem diffusion has not reached mass-market adoption yet. We review theoretical basis for energy system transition based on which we suggest a series of exploratory propositions for prosumer role in initiating the Smart Grid innovation ecosystem.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Department of Industrial Management, Research group: Center for Innovation and Technology Research, Department of Electrical Engineering, Research area: Power engineering
Contributors: Kotilainen, K., Mäkinen, S. J., Järventausta, P., Rautiainen, A., Markkula, J.
Publication date: 25 Jul 2016

Host publication information

Title of host publication: 2016 13th International Conference on the European Energy Market, EEM 2016
Publisher: IEEE COMPUTER SOCIETY PRESS
ISBN (Electronic): 9781509012978
ASJC Scopus subject areas: Marketing, Energy Engineering and Power Technology, Fuel Technology
Keywords: demand response, diffusion of innovation, Flexible electrical energy system, innovation ecosystem, prosumer, Smart Grid
Source: Scopus
Source ID: 84983320429

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

A generalized frame of reference for the incorporation of, multi-terminal VSC-HVDC systems in power flow solutions

This paper introduces a new and general frame-of-reference for true unified, iterative solutions of AC/DC power flows using the Newton-Raphson method. The emphasis is placed on the so-called multi-terminal VSC-HVDC systems. This frame-of-reference accommodates quite naturally any number of AC/DC sub-networks generated by an arbitrary number of VSC converters. Besides, each AC sub-network may contain any number of FACTS devices. The modeling approach adopted for the multi-terminal VSC-HVDC systems is incremental in nature. An AC system of arbitrary configuration is connected to the high-voltage side of the VSC's LTC transformer. In turn, the DC side of each pairing VSC is linked to a DC system of arbitrary configuration. The new model represents a paradigm shift in the way the fundamental frequency, positive sequence modeling of VSC-HVDC links are modeled, where the VSCs are not treated as idealized, controllable voltage sources but rather as compound transformer devices with which key control properties of the PWM-based converters are linked. In contrast to other contemporary approaches, the power flow iterative solutions carried out using the reference frame put forward in this paper exhibits a true quadratic convergence characteristic - in most credible cases, convergence to a tight power mismatch tolerance of e-12 would be achieved in five or less iterations.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Electrical Engineering, Research area: Power engineering, Department of Electrical Engineering
Contributors: Acha, E., Castro, L. M.
Number of pages: 10
Pages: 415-424
Publication date: 1 Jul 2016
Peer-reviewed: Yes

Publication information

Journal: Electric Power Systems Research
Volume: 136
ISSN (Print): 0378-7796
Ratings: 
  • Scopus rating (2016): CiteScore 4.6 SJR 1.032 SNIP 1.517
Original language: English
ASJC Scopus subject areas: Energy Engineering and Power Technology, Electrical and Electronic Engineering
Keywords: MT-HVDC systems, Newton-Raphson method, Power flows, VSC-HVDC modeling
Source: Scopus
Source ID: 84962658013

Research output: Contribution to journalArticleScientificpeer-review

Modeling of the catalytic effects of potassium and calcium on spruce wood gasification in CO2

Using previously reported thermogravimetric analysis measurements, the effects of calcium and potassium on the char gasification rate of spruce wood were modeled. Spruce wood was leached of inorganic ash elements and doped with measured amounts of potassium and calcium. The wood was gasified in an isothermal thermogravimetric analysis device in CO2 where the devolatilization of the wood, char formation and char gasification all occurred inside the preheated reactor. A new method for separating the effects of devolatilization and char gasification is presented. Kinetic models were evaluated for their ability to describe the observed catalytic effects of potassium and calcium on the gasification rate. Two modified versions of the random pore model were able to accurately describe the measured conversion rates and the parameters of the kinetic models were found to be dependent on the calcium and potassium concentrations. Empirical correlations were developed to predict the char conversion rate from only the potassium and calcium concentration of the sample.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Industrial Bioengineering and Applied Organic Chemistry, Johan Gadolin Process Chemistry Centre, Abo Akademi University, VTT Technical Research Centre of Finland
Contributors: Kramb, J., DeMartini, N., Perander, M., Moilanen, A., Konttinen, J.
Number of pages: 10
Pages: 50-59
Publication date: 1 Jul 2016
Peer-reviewed: Yes

Publication information

Journal: Fuel Processing Technology
Volume: 148
ISSN (Print): 0378-3820
Ratings: 
  • Scopus rating (2016): CiteScore 6.8 SJR 1.397 SNIP 1.769
Original language: English
ASJC Scopus subject areas: Fuel Technology, Energy Engineering and Power Technology, Chemical Engineering(all)
Keywords: Biomass, Gasification, Modeling, Reaction kinetics

Bibliographical note

EXT=”Moilanen, Antero"

Source: Scopus
Source ID: 84959431503

Research output: Contribution to journalArticleScientificpeer-review

Liquid fertilizer products from anaerobic digestion of food waste: Mass, nutrient and energy balance of four digestate liquid treatment systems

This study compared four different digestate liquid treatment systems of a theoretical anaerobic digestion plant in order to facilitate the utilization of municipal food waste nutrients in agriculture. The mass, nutrient and energy balances of a theoretical plant digesting 60 kt/y of food waste were used to evaluate the feasibility of the treatments to concentrate nutrients into liquid fertilizer products. The studied technologies for digestate liquid treatment were ammonia stripping, ammonia stripping combined with reverse osmosis (RO), evaporation combined with RO, and stripping combined with both evaporation and RO. As a result, processing of digestate into concentrated fertilizer products consumed less than 10% of the produced energy from food wastes and was also sufficient for the heat-demanding digestate liquid treatments, evaporation and stripping. The digestate liquid treatment systems were considered as nitrogen and potassium concentration methods which were able to concentrate up to 67% of the feedstock nitrogen into transportable fertilizer products with low mass. Of the studied digestate systems evaporation combined with RO was evaluated as the most efficient nutrient recovery technology for the production of transportable fertilizer products due to the high concentration of nutrients and nutrient availability as well as low product mass and energy consumption. Overall, the selection of the treatment technology is dependent on the location of the anaerobic digestion plant relative to the agricultural land and the type of fertilizer products needed.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Industrial Bioengineering and Applied Organic Chemistry, Natural Resources Institute Finland (Luke)
Contributors: Tampio, E., Marttinen, S., Rintala, J.
Number of pages: 11
Pages: 22–32
Publication date: Jul 2016
Peer-reviewed: Yes

Publication information

Journal: Journal of Cleaner Production
Volume: 125
ISSN (Print): 0959-6526
Ratings: 
  • Scopus rating (2016): CiteScore 7.4 SJR 1.659 SNIP 2.53
Original language: English
ASJC Scopus subject areas: Industrial and Manufacturing Engineering, Renewable Energy, Sustainability and the Environment, Environmental Science(all), Strategy and Management
Keywords: Anaerobic digestion, Digestate liquid treatment, Evaporation, Food waste, Reverse osmosis, Stripping
Source: Scopus
Source ID: 84963538041

Research output: Contribution to journalArticleScientificpeer-review

Stand-Off Radioluminescence Mapping of Alpha Emitters under Bright Lighting

Remote detection of alpha emitters is achieved by measuring the secondary radioluminescence light (air fluorescence) that is induced by alpha particles when absorbed in air. A telescope was used to collect the radioluminescence photons to a photomultiplier tube, which is operated in the photon counting mode. Careful matching of photocathode response and filter pass-band allows the sensing of a faint radioluminescence emission in a brightly illuminated environment, which is essential for operative use. A minimum detectable alpha activity of 4 kBq was reached at 1 m distance in 10 s time, when ultraviolet-free lighting is present, and 800 kBq under bright fluorescent lighting. These sensitivities are realized using an ultra-bialkali and cesium-telluride photocathodes in the aforementioned environments respectively. The presented approach is a robust and affordable solution to remotely detect and localize moderate alpha activities in a field environment, providing a means for automated alpha contamination mapping. Moreover, it is shown that a signal increase of more than two orders of magnitude (150-420) can be achieved in deep ultraviolet (close to 260 nm), if nitrogen or argon purge are used to enhance the detection.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Research area: Optics, Research group: Applied Optics, STUK - Radiation and Nuclear Safety Authority, European Commission Joint Research Centre, Institute for Transuranium Elements Karlsruhe, HT Nuclear Ltd
Contributors: Sand, J., Nicholl, A., Hrnecek, E., Toivonen, H., Toivonen, J., Peräjrvi, K.
Number of pages: 7
Pages: 1777-1783
Publication date: 1 Jun 2016
Peer-reviewed: Yes

Publication information

Journal: IEEE Transactions on Nuclear Science
Volume: 63
Issue number: 3
ISSN (Print): 0018-9499
Ratings: 
  • Scopus rating (2016): CiteScore 3.1 SJR 0.566 SNIP 1.048
Original language: English
ASJC Scopus subject areas: Electrical and Electronic Engineering, Nuclear Energy and Engineering, Nuclear and High Energy Physics
Keywords: air fluorescence, alpha particle detectors, optical devices, radioluminescence

Bibliographical note

EXT=”Sand, Johan”

Source: Scopus
Source ID: 84979017346

Research output: Contribution to journalArticleScientificpeer-review

Correlation of wear and work in dual pivoted jaw crusher tests

A laboratory sized jaw crusher with uniform movement of the jaws, the Dual Pivoted Jaw Crusher (DPJC), was used to determine the relationship between wear and work. Wear was concentrated on the jaw plates opposing each other and was measured as mass loss of the specimens. Work was measured directly from the force and the displacement of the instrumented jaw, which allowed work to accumulate only from the actual crushing events. The tests were conducted with several jaw geometries and with two motional settings, where the relation of compressive and sliding motion between the jaws was varied.
The comminution of rock is presumed to be irreversible, meaning that the energy used for crack formation in the rock particles eventually results in the fracture of the particles. Therefore, the amount of energy needed to comminute rock particles should be roughly constant and not dependent on the loading conditions, if the speed of the loading contact is not changed. The DPJC test method allows the separation of work components into comminution specific work and sliding specific work. The results can be used to compare the crushability of minerals without the influence of the used test geometry or the selected jaw plate materials. The sliding work can be used for the comparison of the wear of the jaw plate materials

General information

Publication status: Published
MoE publication type: D3 Professional conference proceedings
Organisations: Materials Science, Research group: Materials Characterization, Research group: Materials Characterization, Metso Minerals, Inc.
Contributors: Terva, J., Valtonen, K., Siitonen, P., Kuokkala, V.
Publication date: Jun 2016

Host publication information

Title of host publication: The 17th Nordic Symposium on Tribology - NORDTRIB 2016
ASJC Scopus subject areas: Materials Science(all), Engineering (miscellaneous), Energy (miscellaneous)
Keywords: Jaw crusher, Comminution, Work, Wear, Abrasive wear
Electronic versions: 

Research output: Chapter in Book/Report/Conference proceedingConference contributionProfessional

Power quality in distribution networks with electric vehicle charging - A research methodology based on field tests and real data

In this paper power quality measurement results of electric vehicle (EV) battery charging are presented. The power quality issues of EV charging are a rising concern among power utilities, as a rapid penetration of EVs on automotive markets is expected to happen in a few years to come. For evaluating the impact of EV charging a series of field measurements are conducted and harmonic current profiles based on the measurements were created. Paper also discusses the calculation methodology of harmonic current flow in distribution networks using the harmonic profiles. For this purpose an OpenDSS based calculation tool is developed and preliminary simulation results are presented.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Department of Electrical Engineering, Research area: Power engineering
Contributors: Supponen, A., Rautiainen, A., Markkula, J., Mäkinen, A., Järventausta, P., Repo, S.
Publication date: 20 May 2016

Host publication information

Title of host publication: 2016 11th International Conference on Ecological Vehicles and Renewable Energies, EVER 2016
Publisher: IEEE
ISBN (Print): 9781509024643
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Automotive Engineering
Keywords: Distribution Network Analysis, Electric Vechicles, Harmonic currents, OpenDSS, Power Quality

Bibliographical note

INT=dee,"Supponen, Antti"

Source: Scopus
Source ID: 84974530660

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Influence of As/group-III flux ratio on defects formation and photovoltaic performance of GaInNAs solar cells

The correlation between the As to group III flux ratio and photovoltaic performance of GaIn0.1N0.03As solar cells fabricated by molecular beam epitaxy is systematically investigated. The results show that flux ratio has a remarkable influence on the formation of defect traps. Furthermore, the formation of defects at different flux ratios is correlating with the variation of the background doping level and the photovoltaic performance. In particular, this study reveals a linear dependency between current generation, dark saturation current, defect densities, photoluminescence peak intensity and the flux ratio. A significant increase in solar cell performance, exhibiting maximum external quantum efficiency of 90%, is obtained when As/group-III ratio is decreased close to the stoichiometric limit. For optimized growth condition, the 1 eV GaIn0.1N0.03As solar cell exhibits a short circuit current density as high as 17.9 mA/cm2 calculated from the external quantum efficiency data (AM0 conditions) with 870 nm high-pass filter. This value reflects the potential of the GaInNAs cell for current matching and power generation in high efficiency solar cells incorporating three- or four- junctions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Optoelectronics Research Centre, Research group: Semiconductor Technology and Applications
Contributors: Polojärvi, V., Aho, A., Tukiainen, A., Raappana, M., Aho, T., Schramm, A., Guina, M.
Number of pages: 8
Pages: 213-220
Publication date: 1 May 2016
Peer-reviewed: Yes

Publication information

Journal: Solar Energy Materials and Solar Cells
Volume: 149
ISSN (Print): 0927-0248
Ratings: 
  • Scopus rating (2016): CiteScore 8.8 SJR 1.599 SNIP 1.697
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Electronic, Optical and Magnetic Materials, Surfaces, Coatings and Films
Keywords: Defects, Dilute nitrides, III-V semiconductors, Material characterization, Molecular beam epitaxy, Multijunction solar cells
Source: Scopus
Source ID: 84957536411

Research output: Contribution to journalArticleScientificpeer-review

Effect of Hole Transporting Material on Charge Transfer Processes in Zinc Phthalocyanine Sensitized ZnO Nanorods

The photoinduced electron transfer processes were studied for hybrid systems consisting of self-assembled monolayer of zinc phthalocyanine (ZnPc) assembled on ZnO nanorods and a film of organic hole transporting material (HTM) atop. Polythiophene (P3HT) or Spiro-OMeTAD were used as HTM. The study was carried out by ultrafast transient absorption spectroscopy technique with selective excitation of ZnPc at 680 nm or P3HT at 500 nm. Data analysis revealed that photoexcitation of ZnPc in the structure ZnO|ZnPc|P3HT results in a fast (1.8 ps) electron transfer from ZnPc to ZnO, which is followed by a hole transfer from the ZnPc cation to P3HT roughly in 30 ps. However, in the case of ZnO|ZnPc|Spiro-OMeTAD structure, the primary reaction upon excitation of ZnPc is a fast (0.5 ps) hole transfer from ZnPc to Spiro-OMeTAD, and the second step is electron injection from the ZnPc anion to ZnO in roughly 120 ps. Thus, we demonstrate two structurally very similar hybrid architectures that implement two different mechanisms for photoinduced charge separation found in dye-sensitized or in organic solar cells.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Supramolecular photochemistry
Contributors: Hakola, H., Sariola-Leikas, E., Efimov, A., Tkachenko, N. V.
Number of pages: 8
Pages: 7044-7051
Publication date: 21 Apr 2016
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 120
Issue number: 13
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2016): CiteScore 7.9 SJR 1.964 SNIP 1.189
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Electronic, Optical and Magnetic Materials, Surfaces, Coatings and Films, Energy(all)
Source: Scopus
Source ID: 84964529902

Research output: Contribution to journalArticleScientificpeer-review

Antireflection composite coatings for organic solar cells

Experimental studies on increasing the transmittance of a light–receiving element (LRE) by applying an antireflection coating were carried out. As an antireflection coating on the solar furnace, the fluoride composite material MgF2–CaF2 was synthesized. Transmission spectra of the LRE without the antireflection coating and with the antireflection coating were measured. The effect of translucence (increase of transmittance) of the LRE after applying the antireflection coating is observed in the spectral region of 0.4–1.1 μm.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Academy of Sciences of the Republic of Uzbekistan, Ohio State University
Contributors: Suleimanov, S. K., Berger, P., Dyskin, V. G., Dzhanklich, M. U., Bugakov, A. G., Dudko, O. A., Kulagina, N. A., Kim, M.
Number of pages: 2
Pages: 157-158
Publication date: 1 Apr 2016
Peer-reviewed: Yes

Publication information

Journal: Applied Solar Energy (English translation of Geliotekhnika)
Volume: 52
Issue number: 2
ISSN (Print): 0003-701X
Ratings: 
  • Scopus rating (2016): CiteScore 0.8 SJR 0.238 SNIP 0.742
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment
Source: Scopus
Source ID: 84988345161

Research output: Contribution to journalArticleScientificpeer-review

Ambient-Pressure XPS Study of a Ni-Fe Electrocatalyst for the Oxygen Evolution Reaction

Chemical analysis of solid-liquid interfaces under electrochemical conditions has recently become feasible due to the development of new synchrotron radiation techniques. Here we report the use of "tender" X-ray ambient-pressure X-ray photoelectron spectroscopy (APXPS) to characterize a thin film of Ni-Fe oxyhydroxide electrodeposited on Au as the working electrode at different applied potentials in 0.1 M KOH as the electrolyte. Our results show that the as-prepared 7 nm thick Ni-Fe (50% Fe) film contains Fe and Ni in both their metallic as well as oxidized states, and undergoes further oxidation when the sample is subjected to electrochemical oxidation-reduction cycles. Metallic Fe is oxidized to Fe3+ and metallic Ni to Ni2+/3+. This work shows that it is possible to monitor the chemical nature of the Ni-Fe catalyst as a function of potential when the corresponding current densities are small. This allows for operando measurements just above the onset of OER; however, current densities as they are desired in photoelectrochemical devices (∼1-10 mA cm-2) could not be achieved in this work, due to ohmic losses in the thin electrolyte film. We use a two-dimensional model to describe the spatial distribution of the electrochemical potential, current density, and pH as a function of the position above the electrolyte meniscus, to provide guidance toward enabling the acquisition of operando APXPS at high current density. The shifts in binding energy of water with applied potential predicted by the model are in good agreement with the experimental values.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Optoelectronics Research Centre, Research group: Surface Science, SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, Department of Chemical and Biomolecular Engineering, Berkeley, Materials Sciences Division, Lawrence Berkeley National Laboratory, Materials and Corrosion Engineering, Exponent, Inc., Polymer Science and Materials Chemistry
Contributors: Ali-Löytty, H., Louie, M. W., Singh, M. R., Li, L., Sanchez Casalongue, H. G., Ogasawara, H., Crumlin, E. J., Liu, Z., Bell, A. T., Nilsson, A., Friebel, D.
Number of pages: 7
Pages: 2247-2253
Publication date: 4 Feb 2016
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 120
Issue number: 4
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2016): CiteScore 7.9 SJR 1.964 SNIP 1.189
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Electronic, Optical and Magnetic Materials, Surfaces, Coatings and Films, Energy(all)
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 84957588014

Research output: Contribution to journalArticleScientificpeer-review

Planning land use for biogas energy crop production: The potential of cutaway peat production lands

Each year, thousands of hectares of peatland that had been harvested are being released in Finland, which can offer an opportunity to increase energy crops and attain the bioenergy targets for non-agriculture lands. In this study, the Geographic Information System (GIS) method was used to improve the assessment of decentralized renewable energy resources. The amount of peat production lands and future cutaway areas for energy crop production was calculated as a case study by using ArcGIS and the Finnish Topographic database. There are almost 1000 km2 of peat production lands in Finland, and theoretically, approximately 300 km2 of cutaway peatlands could be used for energy crops after 30 years. The dry biomass yield of reed canary grass (Phalaris arundinacea) or timothy-fescue grass (mix of Phleum pratense and Festuca pratensis) could be higher than 100 Gg a-1 in these lands indicating methane potential of approximately 300 GWh. The exhausted peat production areas in the western region of Finland have significant potential for use for energy crops; North and South Ostrobothnia account for almost 45% of the total peat production land. A future goal could be to use the cutaway peat production lands more efficiently for bioenergy to mitigate climate change. Since the use of wastelands (including peatlands) are being considered in Europe as a way to avoid competition with food production, the GIS method used in the study to identify suitable peat lands could be applicable to biomass resource studies being conducted in many countries.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Industrial Bioengineering and Applied Organic Chemistry, University of Jyväskylä
Contributors: Laasasenaho, K., Lensu, A., Rintala, J.
Number of pages: 8
Pages: 355-362
Publication date: 1 Feb 2016
Peer-reviewed: Yes

Publication information

Journal: Biomass & Bioenergy
Volume: 85
ISSN (Print): 0961-9534
Ratings: 
  • Scopus rating (2016): CiteScore 6.4 SJR 1.198 SNIP 1.411
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Forestry, Renewable Energy, Sustainability and the Environment, Waste Management and Disposal
Keywords: Bioenergy, Festuca pratensis, GIS, Phalaris arundinacea, Phleum pratense, Wasteland

Bibliographical note

EXT="Laasasenaho, Kari"

Source: Scopus
Source ID: 84953292007

Research output: Contribution to journalArticleScientificpeer-review

Microbial electrochemical technologies with the perspective of harnessing bioenergy: Maneuvering towards upscaling

Microbial electrochemical technologies have gained much attention in the recent years during which basic research has been carried out to provide proof of concept by utilizing microorganisms for generating bioenergy in an electro redox active environment. However, these bio-electrocatalyzed systems pose significant challenges towards up-scaling and practical applications. Various parameters viz., electrodes, materials, configuration, biocatalyst, reaction kinetics, fabrication and operational costs, resistance for electron transfer etc. will critically govern the performance of microbial catalyzed electrochemical systems. Majorly, the surface area of electrode materials, biofilm coverage on the electrode surface, enrichment of electrochemically active electrode respiring bacteria and reduction reactions at cathode will aid in increasing the reaction kinetics towards the upscaling of microbial electrochemical technologies. Enrichment of electroactive microbial community on anode electrode can be promoted with electrode pretreatment, controlled anode potential or electrical current, external resistance, optimal operation temperature, chemical additions and bioaugmentation. Inhibition of the growth of methanogens also increases the columbic efficiency, an essential parameter that determines the efficacy of bioelectricity generation. Considering the practical implementation of these microbial electrochemical technologies, the current review addresses the challenges and strategies to improve the performance of bio-electrocatalyzed systems with respect to the operational, physico-chemical and biological factors towards scale up. Besides, the feasibility for long term operation, the scope for future research along with the operational and maintenance costs are discussed to provide a broad spectrum on the role of the system components for the implementation of these bio-electrochemical technologies for practical utility.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Department of Chemistry and Bioengineering, Research group: Industrial Bioengineering and Applied Organic Chemistry, CSIR-Indian Institute of Chemical Technology, Indian Institute of Technology, Delhi, India, Department of Environmental Engineering, Yildiz Technical University, Department of Chemical Engineering, Bioengineering and Environmental Sciences (BEES), CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Sustainable Environergy Research Laboratory (SERL), Indian Institute of Technology Delhi
Contributors: Butti, S. K., Velvizhi, G., Sulonen, M. L. K., Haavisto, J. M., Oguz Koroglu, E., Yusuf Cetinkaya, A., Singh, S., Arya, D., Annie Modestra, J., Vamsi Krishna, K., Verma, A., Ozkaya, B., Lakaniemi, A., Puhakka, J. A., Venkata Mohan, S.
Pages: 462-476
Publication date: Jan 2016
Peer-reviewed: Yes

Publication information

Journal: Renewable and Sustainable Energy Reviews
Volume: 53
ISSN (Print): 1364-0321
Ratings: 
  • Scopus rating (2016): CiteScore 12.9 SJR 2.998 SNIP 3.543
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment
Keywords: Biocatalyst, Bioelectrochemical system, Electrode materials, Fuel celldesign, Microbial fuelcell
Source: Scopus
Source ID: 84942275042

Research output: Contribution to journalReview ArticleScientificpeer-review

High efficiency dilute nitride solar cells: Simulations meet experiments

Parameter extraction procedure and simulation of dilute nitride solar cells are reported. Using PC1D simulation and fitting to experimental current-voltage and external quantum efficiency data, we retrieve the phenomenological material parameters for GaInNAs solar cells. Based on these, we have constructed a model that can explain the changes in short circuit current and open circuit voltage of n-i-p solar cells subjected to rapid thermal annealing. The model reveals that non-annealed MBE-grown GaInNAs material has an n-type doping that evolves to p-type upon rapid thermal annealing. The change of doping type and the shift of the physical location of the pn-junction were confirmed by Kelvin-probe force microscopy. The PC1D modelling was found to work well also for GaInNAs p-i-n solar cells with opposite polarity. It was also found that the GaInNAs lower doping levels in p-i-n solar cells grown at lowered As/III flux ratios were associated with increased carrier lifetimes.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Optoelectronics Research Centre, Research group: Semiconductor Technology and Applications
Contributors: Tukiainen, A., Aho, A., Polojärvi, V., Ahorinta, R., Guina, M.
Number of pages: 20
Pages: 113-132
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: Journal of Green Engineering
Volume: 5
Issue number: 3-4
Article number: 8
ISSN (Print): 1904-4720
Ratings: 
  • Scopus rating (2016): CiteScore 0.7 SJR 0.132 SNIP 0.294
Original language: English
ASJC Scopus subject areas: Environmental Engineering, Energy(all), Physics and Astronomy(all), Materials Science(all)
Source: Scopus
Source ID: 84983050025

Research output: Contribution to journalArticleScientificpeer-review

Influence of temperature-induced copper diffusion on degradation of selective chromium oxy-nitride solar absorber coatings

Temperature-induced copper diffusion process and its influences on optical degradation and long-term stability of solar absorber coatings on copper substrates were investigated at intermediate temperatures of 248-500. °C. The studied absorbers were sputtered chromium oxy-nitride absorbers having tin oxide anti-reflection coatings. The absorbers were aged by means of thermal accelerated ageing studies and short-period heat treatments up to 500. °C for two hours.Ageing mechanisms and degradation of the absorbers were analysed before and after the ageing studies by optical measurements (solar absorptance with a UV/Vis/NIR spectrophotometer and thermal emittance by FTIR spectrophotometry), microstructural analysis using a field-emission scanning electron microscope (FESEM) equipped with an energy dispersive X-ray spectrometer (EDS) and a transmission electron microscope (TEM) with an EDS, composition by time-of-flight elastic recoil detection analysis (TOF-ERDA) and an X-ray photoelectron spectroscope (XPS), and adhesion by tensile test. The relation between optical degradation and diffusion mechanisms was studied using optical modelling and simulation. The results clearly revealed the mechanism of outward copper diffusion: diffusion of copper substrate atoms into the coating and through the coating to the surface, formation of copper oxide islands on the surface of the coating, and formation of voids in the substrate surface. The relation between the diffusion mechanisms and increase in thermal emittance of the absorber surface was demonstrated.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Research group: Surface Engineering, Research group: Materials Characterization, University of Helsinki
Contributors: Kotilainen, M., Honkanen, M., Mizohata, K., Vuoristo, P.
Number of pages: 10
Pages: 323-332
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: Solar Energy Materials and Solar Cells
Volume: 145
ISSN (Print): 0927-0248
Ratings: 
  • Scopus rating (2016): CiteScore 8.8 SJR 1.599 SNIP 1.697
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Electronic, Optical and Magnetic Materials, Surfaces, Coatings and Films
Keywords: Coating, Copper, Diffusion mechanisms, Solar absorber, Thermal diffusion, Void growth
Source: Scopus
Source ID: 84949090386

Research output: Contribution to journalArticleScientificpeer-review

Roll-to-roll application of photocatalytic TiO2 nanoparticles for printed functionality

In this work ultraviolet A (UVA) light controlled photocatalytic activity of TiO2 nanoparticles is utilized on paper, paperboard, and plastic films for controlled wetting and oxygen sensors for modified atmosphere packages (MAPs). A liquid flame spray (LFS) process is used for a large-area TiO2 nanoparticle deposition on natural fibre based substrates such as paperboard that results in a superhydrophobic surface. Controlled wettability is achieved using an UVA light activation that converts the surface to hydrophilic whereas an oven heat treatment recovers the initial superhydrophobicity. On the other hand, a TiO2 nanoparticles with methylene blue (MB) dye is used to detect the presence of oxygen in modified atmosphere packages. We believe that photocatalytically active surfaces with tailorable properties will find many applications in the near future, for example, with printed functional devices.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Department of Physics, Research area: Aerosol Physics, Research group: Aerosol Synthesis, Center for Functional Materials at Biological Interfaces (FUNMAT), Abo Akad Univ, Abo Akademi University, Dept Phys, Omya International AG, AGH University of Science and Technology, Aerosol Physics Laboratory
Contributors: Saarinen, J. J., Valtakari, D., Bollström, R., Stepien, M., Haapanen, J., Mäkelä, J. M., Toivakka, M.
Number of pages: 4
Pages: 47-50
Publication date: 2016

Host publication information

Title of host publication: Advanced Manufacturing, Electronics and Microsystems : TechConnect Briefs 2016
Volume: 4
Publisher: TechConnect
ISBN (Electronic): 9780997511734
ASJC Scopus subject areas: Fluid Flow and Transfer Processes, Biotechnology, Surfaces, Coatings and Films, Fuel Technology
Keywords: Controlled wetting, Nanoparticles, O sensor, Photocatalysis, TiO
Source: Scopus
Source ID: 84988974879

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

The formation and physical properties of the particle emissions from a natural gas engine

Natural gas engine particle emissions were studied using an old gasoline engine modified to run with natural gas. The tests were steady-state tests performed on two different low loads in an engine dynamometer. Exhaust particle number concentration, size distribution, volatility and electric charge were measured. Exhaust particles were observed to have peak diameters below 10 nm. To get the full picture of particle emissions from natural gas engines, size range 1-5 nm is relevant and important to take into consideration. A particle size magnifier (PSM) was used in this engine application for measuring particles smaller than 3 nm and it proved to be a useful instrument when measuring natural gas engine exhaust particles. It is concluded that the detected particles probably originated from the engine cylinders or their vicinity and grew to detectable sizes in the sampling process because a small fraction of the particles were observed to carry electric charge and the particles did not evaporate totally at 265°C.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Research area: Aerosol Physics, Research group: The Instrumentation, Emissions, and Atmospheric Aerosols Group, Engineering materials science and solutions (EMASS), Urban circular bioeconomy (UrCirBio), Atmospheric Composition Research, VTT Technical Research Centre of Finland, Finnish Meteorological Institute
Contributors: Alanen, J., Saukko, E., Lehtoranta, K., Murtonen, T., Timonen, H., Hillamo, R., Karjalainen, P., Kuuluvainen, H., Harra, J., Keskinen, J., Rönkkö, T.
Number of pages: 7
Pages: 155-161
Publication date: 15 Dec 2015
Peer-reviewed: Yes

Publication information

Journal: Fuel
Volume: 162
ISSN (Print): 0016-2361
Ratings: 
  • Scopus rating (2015): CiteScore 6.9 SJR 1.781 SNIP 2.111
Original language: English
ASJC Scopus subject areas: Fuel Technology, Energy Engineering and Power Technology, Chemical Engineering(all), Organic Chemistry
Keywords: Fine particle emission, Internal combustion engine, Natural gas, Particle formation
Source: Scopus
Source ID: 84941782885

Research output: Contribution to journalArticleScientificpeer-review

Metabolic engineering of Acinetobacter baylyi ADP1 for removal of Clostridium butyricum growth inhibitors produced from lignocellulosic hydrolysates

Background: Pretreatment of lignocellulosic biomass can produce inhibitory compounds that are harmful for microorganisms used in the production of biofuels and other chemicals from lignocellulosic sugars. Selective inhibit