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  • 1.
    Alvfors, Per
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Arnell, Jenny
    IVL.
    Berglin, Niklas
    Innventia.
    Björnsson, Lovisa
    LU.
    Börjesson, Pål
    LU.
    Grahn, Maria
    Chalmers/SP.
    Harvey, Simon
    Chalmers.
    Hoffstedt, Christian
    Innventia.
    Holmgren, Kristina
    IVL.
    Jelse, Kristian
    IVL.
    Klintbom, Patrik
    Kusar, Henrik
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Lidén, Gunnar
    LU.
    Magnusson, Mimmi
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Pettersson, Karin
    Chalmers.
    Rydberg, Tomas
    IVL.
    Sjöström, Krister
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Stålbrand, Henrik
    LU.
    Wallberg, Ola
    LU.
    Wetterlund, Elisabeth
    LiU.
    Zacchi, Guido
    LU.
    Öhrman, Olof
    ETC Piteå.
    Research and development challenges for Swedish biofuel actors – three illustrative examples: Improvement potential discussed in the context of Well-to-Tank analyses2010Report (Other academic)
    Abstract [en]

    Currently biofuels have strong political support, both in the EU and Sweden. The EU has, for example, set a target for the use of renewable fuels in the transportation sector stating that all EU member states should use 10% renewable fuels for transport by 2020. Fulfilling this ambition will lead to an enormous market for biofuels during the coming decade. To avoid increasing production of biofuels based on agriculture crops that require considerable use of arable area, focus is now to move towards more advanced second generation (2G) biofuels that can be produced from biomass feedstocks associated with a more efficient land use. Climate benefits and greenhouse gas (GHG) balances are aspects often discussed in conjunction with sustainability and biofuels. The total GHG emissions associated with production and usage of biofuels depend on the entire fuel production chain, mainly the agriculture or forestry feedstock systems and the manufacturing process. To compare different biofuel production pathways it is essential to conduct an environmental assessment using the well-to-tank (WTT) analysis methodology. In Sweden the conditions for biomass production are favourable and we have promising second generation biofuels technologies that are currently in the demonstration phase. In this study we have chosen to focus on cellulose based ethanol, methane from gasification of solid wood as well as DME from gasification of black liquor, with the purpose of identifying research and development potentials that may result in improvements in the WTT emission values. The main objective of this study is thus to identify research and development challenges for Swedish biofuel actors based on literature studies as well as discussions with the the researchers themselves. We have also discussed improvement potentials for the agriculture and forestry part of the WTT chain. The aim of this study is to, in the context of WTT analyses, (i) increase knowledge about the complexity of biofuel production, (ii) identify and discuss improvement potentials, regarding energy efficiency and GHG emissions, for three biofuel production cases, as well as (iii) identify and discuss improvement potentials regarding biomass supply, including agriculture/forestry. The scope of the study is limited to discussing the technologies, system aspects and climate impacts associated with the production stage. Aspects such as the influence on biodiversity and other environmental and social parameters fall beyond the scope of this study. We find that improvement potentials for emissions reductions within the agriculture/forestry part of the WTT chain include changing the use of diesel to low-CO2-emitting fuels, changing to more fuel-efficient tractors, more efficient cultivation and manufacture of fertilizers (commercial nitrogen fertilizer can be produced in plants which have nitrous oxide gas cleaning) as well as improved fertilization strategies (more precise nitrogen application during the cropping season). Furthermore, the cultivation of annual feedstock crops could be avoided on land rich in carbon, such as peat soils and new agriculture systems could be introduced that lower the demand for ploughing and harrowing. Other options for improving the WTT emission values includes introducing new types of crops, such as wheat with higher content of starch or willow with a higher content of cellulose. From the case study on lignocellulosic ethanol we find that 2G ethanol, with co-production of biogas, electricity, heat and/or wood pellet, has a promising role to play in the development of sustainable biofuel production systems. Depending on available raw materials, heat sinks, demand for biogas as vehicle fuel and existing 1G ethanol plants suitable for integration, 2G ethanol production systems may be designed differently to optimize the economic conditions and maximize profitability. However, the complexity connected to the development of the most optimal production systems require improved knowledge and involvement of several actors from different competence areas, such as chemical and biochemical engineering, process design and integration and energy and environmental systems analysis, which may be a potential barrier.

  • 2.
    Alvfors, Per
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Svedberg, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Modelling of the simultaneous calcination, sintering and sulphation of limestone and dolomite1992In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 47, no 8, p. 1903-1912Article in journal (Refereed)
    Abstract [en]

    The partially sintered spheres model, describing the sulphation of a sorbent particle consisting of CaO and inert content, is incorporated in a model taking into account the calcination of the limestone or dolomite and the sintering of the nascent oxide resulting from the calcination. The model is applicable, for example, to the sulphation of limestone or dolomite when injected into the furnace of a pulverized coal-fired boiler. The simulations show a temperature optimum in the calcium conversion. Increased calcium conversion is found when inert material is present. Satisfactory experimental verifications of the model are shown.

  • 3.
    Alvfors, Per
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Svedberg, Gunnar
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Modelling of the sulphation of calcined limestone and dolomite—a gas-solid reaction with structural changes in the presence of inert solids1988In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 43, no 5, p. 1183-1193Article in journal (Refereed)
    Abstract [en]

    The partially sintered spheres model is further developed to account for the influence of inert material present in the solid reactant. This model is applicable, for example, to the sulphation of CaO with a variable amount of inert material. An example is the reaction between calcined dolomite, CaO·MgO, and SO2, when used as an SO2 sorbent in a boiler furnace. The results show that the rate of reaction increases and the active part of the sorbent reaches a higher degree of conversion when inert material is present.

  • 4. Chutichai, Bhawasut
    et al.
    Im-Orb, Karittha
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Arpornwichanop, Amoynchai
    Design of an integrated biomass gasification and proton exchange membrane fuel cell system under self-sustainable conditions: Process modification and heat-exchanger network synthesis2017In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 42, no 1, p. 448-458Article in journal (Refereed)
    Abstract [en]

    The design and analysis of an integrated biomass gasification and PEMFC system to generate heat and power demand for residential applications are presented in this study. Two biomass gasification configurations using sawdust as a feedstock are considered: air steam biomass gasification (AS-BG-PEMFC) and steam-only biomass gasification (SO-BG-PEMFC). The biomass processing consists of a biomass gasification which is used to produce H-2-rich gas (syngas), followed by high- and low-temperature shift reactors and a preferential oxidation reactor. Pinch analysis is performed to evaluate and design a heat-exchanger network in the two biomass gasification systems. The remaining useful heat is recovered and employed for a reactant preparation step and for a heating utility system in a household. The simulation results indicate that the SO-BG-PEMFC generates syngas with a greater H2 content than the AS-BG-PEMFC, resulting in higher fuel processor and electric efficiencies. However, the AS-BG-PEMFC provides a higher thermal efficiency because a high temperature gaseous product is obtained, and more energy is thereby recovered to the system. The total heat and power efficiencies of the AS-BG-PEMFC and the SO-BG-PEMFC are 83% and 70%, respectively. The Sankey diagram of energy flows reveals that the performance improvement depends entirely on the utilization of useful energy in the exhaust gas.

  • 5.
    Folkesson, Anders
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Andersson, Christian
    Lund Univ, Dept Ind Elect Engn & Automat.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alaküla, Mats
    Lund Univ, Dept Ind Elect Engn & Automat.
    Overgaard, Lars
    Bus Chassis Pre Dev Dept, Scania.
    Real life testing of a hybrid PEM fuel cell bus2003In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 118, no 1-2, p. 349-357Article in journal (Refereed)
    Abstract [en]

    Fuel cells produce low quantities of local emissions, if any, and are therefore one of the most promising alternatives to internal combustion engines as the main power source in future vehicles. It is likely that urban buses will be among the first commercial applications for fuel cells in vehicles. This is due to the fact that urban buses are highly visible for the public, they contribute significantly to air pollution in urban areas, they have small limitations in weight and volume and fuelling is handled via a centralised infrastructure.

    Results and experiences from real life measurements of energy flows in a Scania Hybrid PEM Fuel Cell Concept Bus are presented in this paper. The tests consist of measurements during several standard duty cycles. The efficiency of the fuel cell system and of the complete vehicle are presented and discussed. The net efficiency of the fuel cell system was approximately 40% and the fuel consumption of the concept bus is between 42 and 48% lower compared to a standard Scania bus. Energy recovery by regenerative braking saves up 28% energy. Bus subsystems such as the pneumatic system for door opening, suspension and brakes, the hydraulic power steering, the 24 V grid, the water pump and the cooling fans consume approximately 7% of the energy in the fuel input or 17% of the net power output from the fuel cell system.

    The bus was built by a number of companies in a project partly financed by the European Commission's Joule programme. The comprehensive testing is partly financed by the Swedish programme "Den Grona Bilen" (The Green Car). A 50 kW(el) fuel cell system is the power source and a high voltage battery pack works as an energy buffer and power booster. The fuel, compressed hydrogen, is stored in two high-pressure stainless steel vessels mounted on the roof of the bus. The bus has a series hybrid electric driveline with wheel hub motors with a maximum power of 100 kW.

    Hybrid Fuel Cell Buses have a big potential, but there are still many issues to consider prior to full-scale commercialisation of the technology. These are related to durability, lifetime, costs, vehicle and system optimisation and subsystem design. A very important factor is to implement an automotive design policy in the design and construction of all components, both in the propulsion system as well as in the subsystems.

  • 6.
    Folkesson, Anders
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Lindfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Saxe, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Study of the fuel economy improvement potential of fuel cell buses by vehicle simulationArticle in journal (Other academic)
  • 7.
    Guan, Tingting
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    An overview of biomass-fuelled proton exchange membrane fuel cell (PEMFC) systems2015In: CLEAN, EFFICIENT AND AFFORDABLE ENERGY FOR A SUSTAINABLE FUTURE, Elsevier, 2015, p. 2003-2008Conference paper (Refereed)
    Abstract [en]

    PEMFC fuelled by biomass-derived hydrogen is an efficient and sustainable energy system for small-scale residential applications. Gasification and anaerobic digestion combined with steam reforming are seen as the most suitable conversion processes for hydrogen production. Since the biomass-derived hydrogen contains many kinds of contaminants including CO, CO2, H2S, NH3 and N-2, extensive work has been done on the mechanism and mitigation methods for their poisoning the PEMFC. Although the biomass-fuelled PEMFC systems have been tested in several experiments and checked through simulation work for different perspectives, further research and demonstration work are required to improve the system efficiency and reliability. (C) 2015 The Authors. Published by Elsevier Ltd.

  • 8.
    Guan, Tingting
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Cogeneration PEM fuel cell system fuelled by olive mill wastes for its application in an olive oil plantManuscript (preprint) (Other academic)
  • 9.
    Guan, Tingting
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    The economic performance of an integrated biogas plant and Proton Exchange Membrane Fuel Cell Combined Heat and Power system (PEMFC-CHP) in Sweden2014Conference paper (Refereed)
    Abstract [en]

    A Proton Exchange Membrane Fuel Cell Combined Heat and Power system (PEMFC-CHP) fuelled by the hydrogen-rich gas reformed from biogas may be seen as an efficient and sustainable technology. This system can provide electrical and thermal energy dynamically to residential applications. In this study, an assessment of the economic performance of an integrated biogas plant and PEMFC-CHP for Swedish electricity and heat prices is presented. The economic factors considered are the capital and operation & maintenance (O&M) costs of the biogas plant and the PEMFC-CHP, the price of heat and electricity, and the value of the digestate as fertilizer. The analysis includes two cases: 1) both biogas plant and PEMFC-CHP are located on the farm. The farm sells the electricity and heat to the power grid and district heating system, respectively; 2) the PEMFC-CHP is located in a centralized-biogas plant, not on the farm. The manure is transported from farms to the plant. The plant also sells the electricity and heat to the power grid and district heating system. The results show that the farm-based and the centralized biogas plant have almost the same biogas production cost. The electricity cost of today, expected for 2020, and for the break-even of this integrated system are 530, 305 and 197 €/MWh, respectively. With the current trend of the fuel cell industry development, this break-even price may be reached in the near future.

  • 10.
    Guan, Tingting
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Investigation of the prospect of energy self-sufficiency and technical performance of an integrated PEMFC (proton exchange membrane fuel cell), dairy farm and biogas plant system2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 130, p. 685-691Article in journal (Refereed)
    Abstract [en]

    A PEMFC fuelled with hydrogen is known for its high efficiency and low local emissions. However, the generation of hydrogen is always a controversial issue for the application of the PEMFC due to the use of fossil fuel and the possible carbon dioxide emissions. Presently, the PEMFC-CHP fed with renewable fuels, such as biogas, appears to be the most attractive energy converter-fuel combination. In this paper, an integrated PEMFC-CHP, a dairy farm and a biogas plant are studied. A PEMFC-CHP fed with reformate gas from the biogas plant generates electricity and heat to a dairy farm and a biogas plant, while the dairy farm delivers wet manure to the biogas plant as the feedstock for biogas production. This integrated system has been modelled for steady-state conditions by using Aspen Plus (R). The results indicate that the wet manure production of a dairy farm with 300 milked cows can support a biogas plant to give 1280 MW h of biogas annually. Based on the biogas production, a PEMFC-CHP with a stack having an electrical efficiency of 40% generates 360 MW h electricity and 680 MW h heat per year, which is enough to cover the energy demand of the whole system while the total efficiency of the PEMFC-CHP system is 82%. The integrated PEMFC-CHP, dairy farm and biogas plant could make the dairy farm and the biogas plant self-sufficient in a sustainable way provided the PEMFC-CHP has the electrical efficiency stated above. The effect of the methane conversion rate and the biogas composition on the system performance is discussed. Moreover, compared with the coal-fired CUP plant, the potentially avoided fossil fuel consumption and CO2 emissions of this self-sufficient system are also calculated.

  • 11.
    Guan, Tingting
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Chutichai, Bhawasut
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Arpornwichanop, Amornchai
    Biomass-fuelled PEMFC systems: Evaluation of two conversion pathsrelevant for different raw materials2015In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 106, p. 1183-1191Article in journal (Refereed)
    Abstract [en]

    Biomass-fuelled polymer electrolyte membrane fuel cells (PEMFCs) offer a solution for replacing fossilfuel with hydrogen production. This paper uses simulation methods for investigating biomass-fuelledPEMFCs for different raw materials and conversion paths. For liquid and solid biomass, anaerobic diges-tion (AD) and gasification (GF), respectively, are relatively viable and developed conversion technologies.Therefore, the AD-PEMFC system and the GF-PEMFC system are simulated for residential applications inorder to evaluate the performance of the biomass-fuelled PEMFC systems. The results of the evaluationshow that renewable hydrogen-rich gas from manure or forest residues is usable for the PEMFCs andmakes the fuel cell stack work in a stable manner. For 100 kWe generation, the GF-PEMFC system yieldsan excellent technical performance with a 20% electric efficiency and 57% thermal efficiency, whereas theAD-PEMFC system only has an 9% electric efficiency and 13% thermal efficiency due to the low efficiencyof the anaerobic digester (AD) and the high internal heat consumption of the AD and the steam reformer(SR). Additionally, in this study, the environmental performances of the AD-PEMFC and the GF-PEMFC interms of CO2emission offset and land-use efficiency are discussed.

  • 12.
    Görling, Martin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Larsson, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Bio-methane via fast pyrolysis of biomass2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, no SI, p. 440-447Article in journal (Refereed)
    Abstract [en]

    Bio-methane, a renewable vehicle fuel, is today produced by anaerobic digestion and a 2nd generation production route via gasification is under development. This paper proposes a poly-generation plant that produces bio-methane, bio-char and heat via fast pyrolysis of biomass. The energy and material flows for the fuel synthesis are calculated by process simulation in Aspen Plus®. The production of bio-methane and bio-char amounts to 15.5. MW and 3.7. MW, when the total inputs are 23. MW raw biomass and 1.39. MW electricity respectively (HHV basis). The results indicate an overall efficiency of 84% including high-temperature heat and the biomass to bio-methane yield amounts to 83% after allocation of the biomass input to the final products (HHV basis). The overall energy efficiency is higher for the suggested plant than for the gasification production route and is therefore a competitive route for bio-methane production.

  • 13.
    Haraldsson, Kristina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Effects of Ambient Conditions on Fuel Cell Vehicle Performance2005In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 145, no 2, p. 298-306Article in journal (Refereed)
    Abstract [en]

    Ambient conditions have considerable impact on the performance of fuel cell hybrid vehicles. Here, the vehicle fuel consumption, the air compressor power demand, the water management system and the heat loads of a fuel cell hybrid sport utility vehicle (SUV) were studied. The simulation results show that the vehicle fuel consumption increases with 10% when the altitude increases from 0 m up to 3000 m to 4.1 L gasoline equivalents/100 km over the New European Drive Cycle (NEDC). The increase is 19% on the more power demanding highway US06 cycle. The air compressor is the major contributor to this fuel consumption increase. Its load-following strategy makes its power demand increase with increasing altitude. Almost 40% of the net power output of the fuel cell system is consumed by the air compressor at the altitude of 3000 m with this load-following strategy and is thus more apparent in the high-power US06 cycle.

    Changes in ambient air temperature and relative humidity effect on the fuel cell system performance in terms of the water management rather in vehicle fuel consumption. Ambient air temperature and relative humidity have some impact on the vehicle performance mostly seen in the heat and water management of the fuel cell system. While the heat loads of the fuel cell system components vary significantly with increasing ambient temperature, the relative humidity did not have a great impact on the water balance. Overall, dimensioning the compressor and other system components to meet the fuel cell system requirements at the minimum and maximum expected ambient temperatures, in this case 5 and 40 degrees C, and high altitude, while simultaneously choosing a correct control strategy are important parameters for efficient vehicle power train management.

  • 14.
    Haraldsson, Kristina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Folkesson, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Fuel Cell Buses in the Stockholm CUTE Project: First Experiences from a Climate Perspective2005In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 145, no 2, p. 620-631Article in journal (Refereed)
    Abstract [en]

    This paper aims to share the first experiences and results from the operation of fuel cell buses in Stockholm within the Clean Urban Transport for Europe (CUTE) project. The project encompasses implementation and evaluation of both a hydrogen fuel infrastructure and fuel cell vehicles in nine participating European cities. In total, 27 fuel cell buses, 3 in each city, are in revenue service for a period of 2 years.

    The availability of the fuel cell buses has been better than expected, about 85% and initially high fuel consumption has been reduced to approximately 2.2 kg H-2/10 km corresponding to 7.51 diesel equivalents/10 km. Although no major breakdowns have occurred so far, a few cold climate-related issues did arise during the winter months in Stockholm.

  • 15.
    Haraldsson, Kristina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Folkesson, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Saxe, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    A First Report on the Attitude towards Hydrogen Fuel Cell Buses in Stockholm2006In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 31, no 3, p. 317-325Article in journal (Refereed)
    Abstract [en]

    Surveys of the attitude towards hydrogen fuel cell buses among passengers and bus drivers were performed in Stockholm during the autumn of 2004. Another field survey of the attitude of the fuel cell bus passengers is planned towards the end of the CUTE Stockholm project, i.e. during the autumn of 2005.

    The main results from the surveys are:

    People are generally positive towards fuel cell buses and feel safe with the technology.

    Newspapers and bus stops are where most people get information about the buses.

    The passengers, furthermost those above the age of 40, desire more information about fuel cells and hydrogen.

    The drivers are generally positive to the fuel cell bus project.

    Although the environment is rated as an important factor, 64% of the bus passengers were not willing to pay a higher fee if more fuel cell buses were to be used.

  • 16.
    Haraldsson, Kristina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Molin, Andreas
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Cold Climate Thermal Management for Fuel Cells Using Phase Change MaterialsIn: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755Article in journal (Other academic)
  • 17.
    Hedström, Lars
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Holmström, Nicklas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Saxe, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Ridell, Bengt
    Rissanen, Markku
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Operating Experience and Results from 3310 hours of Operation of a Biogas-powered 5 kW SOFC System in GlashusEttManuscript (preprint) (Other academic)
  • 18.
    Hedström, Lars
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Saxe, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Folkesson, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Wallmark, Cecilia
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Haraldsson, Kristina
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Bryngelsson, Mårten
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Key factors in planning a sustainable energy future including hydrogen and fuel cells2006In: Bulletin of Science, Technology & Society, ISSN 0270-4676, E-ISSN 1552-4183, Vol. 26, no 4, p. 264-277Article in journal (Refereed)
    Abstract [en]

    In this article, a number of future energy visions, especiallythose basing the energy systems on hydrogen, are discussed.Some often missing comparisons between alternatives, from asustainability perspective, are identified and then performedfor energy storage, energy transportation, and energy use invehicles. It is shown that it is important to be aware of thelosses implied by production, packaging, distribution, storage,and end-use of hydrogen when suggesting a "hydrogen economy."It is also shown that for stationary electric energy storage,fuel cell electrolyzers could be feasible. Zero-tailpipeemissionvehicles are compared. The battery electric vehicle has thehighest electrical efficiency, but other requirements implythat plug-in hybrids or fuel cell hybrids might be a betteroption in some types of vehicles. Finally, a simplified exampleis applied to the overall results and used to discuss the needsand nature of an energy system based on intermittent energysources. 

  • 19.
    Hedström, Lars
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Tingelöf, Thomas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Experimental results from a 5 kW PEM fuel cell stackoperated on simulated reformate from highly dilutedhydrocarbon fuels: Efficiency, dilution, fuel utilisation,CO poisoning and design criteria2009In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, no 34, p. 1508-1514Article in journal (Refereed)
    Abstract [en]

    The present article analyses the effects of dilute biogas on efficiency, fuel utilisation, dynamics, control strategy, and design criteria for a polymer electrolyte fuel cell (PEFC) system. The tested fuel compositions are exemplified by gas compositions that could be attained within various Swedish biofuel demonstration projects. Experimental data which can serve as a basis for design of PEFC biogas systems operating in load-following, or steady-state mode, are reported for a 5 kW PEFC stack.

  • 20.
    Hedström, Lars
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Wallmark, Cecilia
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Alvfors, Per
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Rissanen, Markku
    Stridh, Bengt
    Ekman, Josefin
    Description and modelling of the solar–hydrogen–biogas-fuel cell system in GlashusEtt2004In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, no 131, p. 340-350Article in journal (Refereed)
    Abstract [en]

    The need to reduce pollutant emissions and utilise the world's available energy resources more efficiently has led to increased attention towards e.g. fuel cells, but also to other alternative energy solutions. In order to further understand and evaluate the prerequisites for sustainable and energy-saving systems, ABB and Fortum have equipped an environmental information centre, located in Hammarby Sjostad, Stockholm, Sweden, with an alternative energy system. The system is being used to demonstrate and evaluate how a system based on fuel cells and solar cells can function as a complement to existing electricity and heat production. The stationary energy system is situated on the top level of a three-floor glass building and is open to the public. The alternative energy system consists of a fuel cell system, a photovoltaic (PV) cell array, an electrolyser, hydrogen storage tanks, a biogas burner, dc/ac inverters, heat exchangers and an accumulator tank. The fuel cell system includes a reformer and a polymer electrolyte fuel cell (PEFC) with a maximum rated electrical output of 4 kW(el) and a maximum thermal output of 6.5 kW(th). The fuel cell stack can be operated with reformed biogas, or directly using hydrogen produced by the electrolyser. The cell stack in the electrolyser consists of proton exchange membrane (PEM) cells. To evaluate different automatic control strategies for the system, a simplified dynamic model has been developed in MATLAB Simulink. The model based on measurement data taken from the actual system. The evaluation is based on demand curves, investment costs, electricity prices and irradiation. Evaluation criteria included in the model are electrical and total efficiencies as well as economic parameters.

  • 21.
    Johansson, Kristina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    The Effect of Drive Cycles on the Performance of a PEM Fuel Cell System for Automotive Applications2001In: Proceedings, ATTCE 2001-Automotive and Transport Technology Congress and Exhibition, 2001, p. 417-426Conference paper (Refereed)
    Abstract [en]

    The purpose of this system study was to compare the performance and fuel consumption of a pure fuel cell vehicle ( i.e. with no battery included) with an internal combustion engine (ICE) vehicle of similar weight in different drive cycles. Both light and heavy duty vehicles are studied.

    For light duty vehicles, the New European drive cycle, NEDC [70/220/EEC], the FTP75 [EPA] and a Swedish driving pattern from the city of Lund [ Ericsson, 2000 ] are utilised. The fuel consumption for these drive cycles was compared with ICE vehicles of similar weight, an Ibiza Stella 1.4 (year 2000) from Seat and a Volvo 960 2.5 E sedan (year 1995). For heavy duty vehicles, urban buses in this study, two drive cycles were employed, the synthetic CBD14 and the real bus route 85 from Gothenburg, Sweden.

    It can be concluded that marked improvements in fuel economy can be achieved for hydrogen-fuelled light and heavy duty vehicles. The fuel consumption of a small fuel cell vehicle was 50% less than the corresponding ICE vehicle in both the NEDC and the FTP75. With proper dimensioning of the system components, e.g. the engine, further reductions in fuel consumption can be achieved. The range of more than 500 km with 5 kg of hydrogen in a 345 bar fuel tank was comparable to an ICE vehicle. If the pressure is raised to 690 bar, a driving range of 600 km could be achieved. As the auxiliary system counteracts the increase in fuel cell efficiency, raising the minimum operating voltage from 0.6 to 0.75 V in a 50 kW fuel cell system, provides only a 5% reduction in fuel consumption. A fuel cell bus operated in the CBD14 and the bus route 85, compared with diesel-fuelled urban bus of similar weight, demonstrates a reduction in fuel consumption of 33 and 37 % respectively.

  • 22. Larsson, M.
    et al.
    Mohseni, F.
    Wallmark, C.
    Grönkvist, Stefan
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Energy system analysis of the implications of hydrogen fuel cell vehicles in the Swedish road transport system2014In: 20th World Hydrogen Energy Conference, WHEC 2014, 2014, p. 2084-2091Conference paper (Refereed)
    Abstract [en]

    The focus on pathways to reduce the use of fossil fuels in the transport sector is intense in many countries worldwide. Considering that biofuels have a limited technical production potential and that battery electric vehicles suffer from technical limitations that put constraints on their general use in the transport sector, hydrogen-fuelled fuel cell vehicles may become a feasible alternative. Introduction of hydrogen in the transport sector will also transform the energy sector and create new interactions. The aim of this paper is to analyse the consequences and feasibility of such an integration in Sweden. Different pathways for hydrogen, electricity and methane to the transport sector are compared with regard to system energy efficiency. The efficiencies for hydrogen and electricity are used for estimating the energy resources needed for hydrogen production and electric vehicles for a future Swedish transport sector based on renewable fuels. The analysis reveal that the well to wheel system efficiencies for hydrogen fuel cell vehicles are comparable to those of methane gas vehicles, even when methane gas is the primary energy source. The results further indicate that an increased hydrogen demand may have a less than expected impact on the primary energy supply in Sweden.

  • 23.
    Larsson, Mårten
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Grönkvist, Stefan
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Barriers and drivers for upgraded biogas in Sweden2013Conference paper (Other academic)
  • 24.
    Larsson, Mårten
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Grönkvist, Stefan
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Synthetic fuels from electricity for the Swedish transport sector: comparison of well to wheel energy efficiencies and costs2015In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, p. 1875-1880Article in journal (Refereed)
    Abstract [en]

    Synthetic fuels based on electricity, water, and carbon dioxide (CO2) may be necessary to cover the fuel demand in a sustainable transport sector based on renewable energy sources. The aim of this paper is to compare hydrogen, methane, methanol and diesel produced in this way. The main parameters for the analysis are well to wheel energy efficiency and costs, and the fuels are analysed in a Swedish context. The results indicate that methane and diesel could have the potential to be cost competitive in the near term, at least if common incentivesfor renewable transportation fuels are applied. Moreover, that hydrogen is the best option in terms of well to wheel energy efficiency, and that it in the longer term also may be cost competitive to the other fuels.

  • 25.
    Larsson, Mårten
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Grönkvist, Stefan
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Upgraded biogas for transport in Sweden: effects of policy instruments on production, infrastructure deployment and vehicle sales2016In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 112, p. 3774-3784Article in journal (Refereed)
    Abstract [en]

    Sweden is a leading country in the development of upgraded biogas for use in the transport sector. The introduction of a new vehicle fuel is complex when the production, infrastructure, and vehicle fleet must be developed simultaneously. The aim of this article is to present and analyse the development of upgraded biogas in the Swedish transport sector in relation to policy instruments and the availability of a natural gas grid. Plausible implications for the future development of the biogas system are also analysed.

    The development of upgraded biogas in Sweden's transport sector is heavily influenced in several ways by domestic policy instruments. Investment support schemes and exemptions from energy and carbon dioxide taxes have been key instruments in initiating the construction of new biogas production facilities and infrastructure. The study of the biogas development in relation to the natural gas grid presented in this article indicates that it may not be necessary to construct a comprehensive network of pipelines for methane (natural gas) to develop the market – at least not initially. In Sweden and elsewhere the biogas volumes will still be quite small in the near future and it is possible to achieve biogas development without an available methane gas grid.

    Public procurement, investment schemes and reduced fringe benefit tax have likely been important policy instruments in the introduction of biogas vehicles, whereas the support for private biogas cars has been short-sighted in some ways, and not sufficient to achieve a competitive cost of ownership for biogas cars in relation to diesel cars.

    The future strategy for biogas should be based on a realistic potential for using biogas in the transport sector; this would determine whether further market expansion is necessary or if incentives should be focused on development of the production side to cover the current demand for vehicle gas.

    The development of biogas production likely depends on continued tax exemptions, which are currently available only until the end of 2015; it is uncertain whether they will remain in place. If biogas should be promoted further among private car owners, more visible incentives for private cars are needed together with incentives for expanding the fuelling infrastructure network.

  • 26.
    Larsson, Mårten
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Görling, Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Bio-methane upgrading of pyrolysis gas from charcoal production2013In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 3, p. 66-73Article in journal (Refereed)
    Abstract [en]

    This article presents a novel route for bio-methane synthesis utilizing pyrolysis gas from charcoal production. It is a retrofit option that may increase overall process efficiency in charcoal production while adding a valuable product. The pyrolysis gas from charcoal production can be used for bio-methane production instead of burning, while the required heat for the charcoal production is supplied by additional biomass. The aim is to evaluate the energy efficiency of bio-methane upgrading from two types of charcoal plants, with and without recovery of liquid by-products (bio-oil). Aspen simulations and calculations of the energy and mass balances are used to analyse the system. The yield of bio-methane compared to the import of additional biomass is estimated to be 81% and 85% (biomass to bio-methane yield) for the syngas case and the pyrolysis vapour case, respectively. When the biomass necessary to produce the needed electricity (assuming ηel = 33%) is included, the yields amount to 65% and 73%. The results show that the suggested process is a competitive production route for methane from lignocellulosic biomass.

  • 27.
    Larsson, Mårten
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Jansson, Mikael
    Innventia, Sweden.
    Grönkvist, Stefan
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Techno-economic assessment of anaerobic digestion in a typical Kraft pulp mill to produce biomethane for the road transport sector2015In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 104, p. 460-467Article in journal (Refereed)
    Abstract [en]

    Renewable waste-based fuels may decrease the resource use and environmental impact of the road transport sector; one of the options is biogas produced via anaerobic digestion of waste streams from pulp and paper mills. This paper describes process simulation and economic assessments for two options for integrating anaerobic digestion and production of liquid biogas in a typical Nordic Kraft pulp mill: (1) a high-rate anaerobic reactor in the wastewater treatment, and (2) an external anaerobic stirred tank reactor for the treatment of primary and secondary sludge as well as Kraft evaporator methanol condensate. The results revealed an annual production potential of 26-27 GWh biogas in an average Nordic Kraft pulp mill, which is equivalent to a daily production of 7600 L of diesel in terms of energy, and the production cost was estimated to (sic)0.47-0.82 per litre diesel equivalent, comparable with the Swedish price of (sic)0.68 per litre diesel.

    However, for the cases with liquid biogas (LBG), a discounted payback period of about 8 years may not be considered profitable by the industry. Other pre-requisites may, however, improve the profitability: a larger mill; production of compressed biogas instead of liquid biogas; or, for case 1, a comparison with the alternative cost for expanding the wastewater treatment capacity with more process equipment for activated sludge treatment. The results reveal that anaerobic digestion at pulp mills may both expand the production of renewable vehicle fuel but also enable increased efficiency and revenue at Kraft pulp mills.

  • 28.
    Larsson, Mårten
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Mosheni, Farzad
    Sweco, Sweden.
    Wallmark, Cecilia
    Sweco, Sweden.
    Grönkvist, Stefan
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Energy system analysis of the implications of hydrogen fuel cell vehicles in the Swedish road transport system2015In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 40, no 35, p. 11722-11729Article in journal (Refereed)
    Abstract [en]

    The focus on pathways to reduce the use of fossil fuels in the transport sector is intense in many countries worldwide. Considering that biofuels have a limited technical production potential and that battery electric vehicles suffer from technical limitations that put constraints on their general use in the transport sector, hydrogen-fuelled fuel cell vehicles may become a feasible alternative. Introduction of hydrogen in the transport sector will also transform the energy sector and create new interactions. The aim of this paper is to analyse the consequences and feasibility of such an integration in Sweden. Different pathways for hydrogen, electricity and methane to the transport sector are compared with regard to system energy efficiency. The well-to-wheel energy efficiencies for hydrogen and electricity are used for estimating the energy resources needed for hydrogen production and electric vehicles for a future Swedish transport sector based on renewable fuels. The analysis reveal that the well-to-wheel system efficiencies for hydrogen fuel cell vehicles are comparable to those of methane gas vehicles, even when biomethane is the energy source. The results further indicate that an increased hydrogen demand may have a less than expected impact on the primary energy supply in Sweden.

  • 29.
    Magnusson, Mimmi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Biogas from mechanical pulping industry: Potential improvement for increased biomass vehicle fuels2012In: Proceedings of the 25th International Conference on Efficiency, Cost, Optimization and Simulation of Energy Conversion Systems and Processes, ECOS 2012, 2012, Vol. 5, p. 56-67Conference paper (Refereed)
    Abstract [en]

    Biogas is a vehicle fuel of the first generation of biofuels with great potential for reducing the climate impact from the transport sector. Today biogas is mainly produced by digestion in Sweden and the total amounts to 1.4 TWhLHV/year (2010) of which about 0.6 TWhLHV is upgraded and used in the transport sector. Using industrial wastewater, e.g. from a pulp and paper mill, as substrate for production of biogas, the amount of renewable fuel to the transport sector could be increased. In the pulping industry, substantial amounts of organic matter are generated; this is commonly treated aerobically to reduce the chemical oxygen demand (COD) in the effluent streams before discharge to a recipient. Treating these effluent streams mainly anaerobically instead could contribute to the transport sector's energy supply. The aim of this study is to investigate the potential for using effluent streams from the Swedish mechanical pulp and paper industry to produce biogas. A typical Swedish mechanical pulp mill is considered for anaerobic treatment of the wastewaters. This type of pulp mill presently uses conventional methods for wastewater treatment to reduce COD, but converting most of this to anaerobic treatment would increase the amount of biogas produced. When considering this conversion in a larger context, supposing that anaerobic treatment would be applied to all Swedish mechanical pulp mills, which stand for about 30% of the total Swedish pulp production, it is shown that the production could amount to as much as 0.5 TWhLHV/year of biogas. This represents about one third of the biogas produced in Sweden today. The main conclusion of this study is that if anaerobic treatment of effluent streams from the pulping industry were introduced, the biogas production in Sweden could be significantly increased, thus moving one step further in reducing the transport sector's climate impact.

  • 30.
    Magnusson, Mimmi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Biogas potential in the Swedish pulp and paper industry2012In: Proceedings of ICCE 2012: International conference on clean energy, 2012, p. 61-68Conference paper (Refereed)
    Abstract [en]

    The European Union target of 10 % renewable fuels in the transport sector by 2020 is still far off, with 2.6% renewables on the EU level (2007) and 5.7% nationally in Sweden (2010). Biogas today accounts for a minor share of the renewable vehicle fuels in Sweden, but has the potential to increase. This study estimates the potential for producing biogas by anaerobic digestion as a part of the wastewater treatment in Swedish pulp and paper mills. The technology is mature and is used for example in municipal wastewater facilities but not as yet in the Swedish pulp and paper industry even though many of the effluent streams are well-suited for it. The results show that applying anaerobic wastewater treatment at Sweden’s pulp and paper mills may render as much as 1 TWhLHV/year, which would increase the present biogas production of 1.4 TWhLHV (2010) by 70%.

  • 31.
    Magnusson, Mimmi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Integrated production of biogas and cellulosic ethanol: A potential source for renewable vehicle fuelsManuscript (preprint) (Other academic)
  • 32.
    Magnusson, Mimmi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Mohseni, Farazad
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Görling, Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Introducing Renewable Electricity to increase Biogas Production Potential2010In: International Conference on Applied Energy 2010, 2010Conference paper (Refereed)
    Abstract [en]

    Facing the challenge of CO2 reduction in the transport sector, the focus on alternative fuels has been growing rapidly. Several fuels and production methods have been proposed which illustrate various aspects of how to contribute to CO2 mitigation.This paper presents how biogas production from a given amount of biomass may be increased. To enhance biogas production, process improvements for today’s digestion process and also biogas produced from biomass gasification are suggested. Both biogas production via digestion and gasification of biomass produce CO2 as a by-product. To increase the biogas production, this green CO2 could be used to produce additional methane using the well-known Sabatier reaction. The hydrogen required for the reaction is proposed to originate from electrolysis of water, where the electricity needed is preferably produced from a renewable source, e.g. wind power. Reusing carbon in such manner reduces the need for fossil methane while supplying fuel to the transport sector.In this study, a base case scenario describing plants of typical sizes and efficiencies is presented for both digestion and gasification. It is shown that, using the Sabatier process on this base case, the methane production from gasification may be increased by about 140 %. For the digestion, the increase, including process improvements, is about 74 %. By using this method more biogas may be produced, without adding new raw material to the process. This would present a great way to meet society’s increasing demand for renewable fuels, while simultaneously reusing CO2.

  • 33.
    Mohseni, Farzad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Görling, Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    The competitiveness of synthetic natural gas as a propellant in the Swedish fuel market2013In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 52, p. 810-818Article in journal (Refereed)
    Abstract [en]

    The road transport sector today is almost exclusively dependent on fossil fuels. Consequently, it will need to face a radical change if it aims to switch from a fossil-based system to a renewable-based system. Even though there are many promising technologies under development, they must also be economically viable to be implemented. This paper studies the economic feasibility of synthesizing natural gas through methanation of carbon dioxide and hydrogen from water electrolysis. It is shown that the main influences for profitability are electricity prices, synthetic natural gas (SNG) selling prices and that the by-products from the process are sold. The base scenario generates a 16% annual return on investment assuming that SNG can be sold at the same price as petrol. A general number based on set conditions was that the SNG must be sold at a price about 2.6 times higher per kWh than when bought in form of electricity. The sensitivity analysis indicates that the running costs weigh more heavily than the yearly investment cost and off-peak production can therefore still be economically profitable with only a moderate reduction of electricity price. The calculations and prices are based on Swedish prerequisites but are applicable to other countries and regions.

  • 34.
    Mohseni, Farzad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Magnusson, Mimmi
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Görling, Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Biogas from renewable electricity: Increasing a climate neutral fuel supply2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 90, no 1, p. 11-16Article in journal (Refereed)
    Abstract [en]

    If considering the increased utilisation of renewable electricity during the last decade, it is realistic to assume that a significant part of future power production will originate from renewable sources. These are normally intermittent and would cause a fluctuating electricity production. A common suggestion for stabilising intermittent power in the grid is to produce hydrogen through water electrolysis thus storing the energy for later. It could work as an excellent load management tool to control the intermittency, due to its flexibility. In turn, hydrogen could be used as a fuel in transport if compressed or liquefied. However, since hydrogen is highly energy demanding to compress, and moreover, has relatively low energy content per volume it would be more beneficial to store the hydrogen chemically attached to carbon forming synthetic methane (i.e. biogas). This paper presents how biogas production from a given amount of biomass could be increased by addition of renewable electricity. Commonly biogas is produced through digestion of organic material. Recently also biomass gasification is gaining more attention and is under development. However, in both cases, a significant amount of carbon dioxide is produced as by-product which is subject for separation and disposal. To increase the biogas yield, the separated carbon dioxide (which is considered as climate neutral) could, instead of being seen as waste, be used as a component to produce additional methane through the well-known Sabatier reaction. In such process the carbon could act as hydrogen carrier of hydrogen originating from water electrolysis driven by renewable sources. In this study a base case scenario, describing biogas plants of typical sizes and efficiencies, is presented for both digestion and gasification. It is assessed that, if implementing the Sabatier process on gasification, the methane production would be increased by about 110%. For the digestion, the increase, including process improvements, would be about 74%. Hence, this method results in greatly increased biogas potential without the addition of new raw material to the process. Additionally, such model would present a great way to meet the transport sector's increasing demand for renewable fuels, while simultaneously reducing net emissions of carbon dioxide.

  • 35.
    Niklasson, Mårten
    et al.
    Lund Institute of Technology.
    Gårsjö, David
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Folkesson, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Sunnerstedt, Eva
    City of Stockholm, Environment and Health Administration.
    Hägvall, Joakim
    FOI.
    Safety issues with hydrogen as a vehicle fuel2005In: Electrical Vehicle Symposium 21: Monaco, 2005, 2005Conference paper (Refereed)
  • 36.
    Saxe, Maria
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Advantages of integration with industry for electrolytic hydrogen production2007In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 32, no 1, p. 42-50Article in journal (Refereed)
    Abstract [en]

    This paper evaluates possible synergies with industry, such as heat and oxygen recovery from the hydrogen production. The hydrogen production technology used in this paper is electrolysis and the calculations include the cost and energy savings for integrated hydrogen production. Electrolysis with heat recovery leads to both cost reduction and higher total energy efficiencies of the hydrogen production. Today about 15–30% of the energy supplied for the production is lost and most of it can be recovered as heat. Utilization of the oxygen produced in electrolysis gives further advantages. The integration potential has been evaluated for a pulp and paper industry and the Swedish energy system, focusing on hydrogen for the transportation sector. The calculated example shows that the use of the by-product oxygen and heat greatly affects the possibility to sell hydrogen produced from electrolysis in Sweden. Most of the energy losses are recovered in the example; even gains in energy for not having to produce oxygen with cryogenic air separation are shown. When considering cost, the oxygen income is the most beneficial but when considering energy efficiency, the heat recovery stands for the greater part.

  • 37.
    Saxe, Maria
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Folkesson, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    A follow-up and conclusive report on the attitude towards hydrogen fuel cell buses in the CUTE project: From passengers in Stockholm to bus operators in Europe2007In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 32, no 17, p. 4295-4305Article in journal (Refereed)
    Abstract [en]

    This paper concerns the attitude towards the fuel cell bus and the hydrogen technology used in the CUTE project, represented by two passenger surveys performed in Stockholm, a survey performed among drivers in four cities and final statements as well as recommendations for future projects by project partners.

    Main results are:

    The passengers' willingness to pay for having more fuel cell buses in public transport was still low after one year of operation.

    Concern about safety is not an issue among passengers or drivers.

    The acceleration was rated as inferior to that of regular buses by 50% of the drivers; this differs from earlier findings in Stockholm.

    The operators were pleased with the reliability of the buses and the trust in the new technology grew stronger during the project period. Main problems were lack of spare parts and insufficient information sharing due to confidentiality.

  • 38.
    Saxe, Maria
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Folkesson, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Energy system analysis of the fuel cell buses operated in the project: Clean Urban Transport for Europe2008In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 33, no 5, p. 689-711Article in journal (Refereed)
    Abstract [en]

    During the project Clean Urban Transport for Europe (CUTE), which ended in May 2006, 27 fuel cell buses were operated in nine European cities. In this paper key performance parameters from the operation of the fuel cell buses in the project are reported, the energy system of the bus is analysed and drive cycle tests in five cities are presented and analysed. The focus of the paper is on fuel consumption and optimisation potential but experiences of, and recommendations for, evaluation in large demonstration projects are also presented. The results show that although the total fuel cell system efficiency was found to be high (36–41%), the fuel consumption was higher for the fuel cell buses than for diesel buses. Since the CUTE buses were a pre-commercial generation of fuel cell buses, with standard auxiliaries and extensive reliability measures, large fuel consumption reduction is possible. Suggestions on how to increase the efficiency is presented in this paper. Minimising the reliability measures would decrease fuel consumption by about 20% and lowering the weight by 2 tonnes would decrease fuel consumption by another 10%. Hybridisation in combination with using electrical auxiliaries could save an additional 5–10% or more.

  • 39.
    Saxe, Maria
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Hedström, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Rissanen, Markku
    ABB AB, Corporate Research.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Ridell, Bengt
    Grontmij AB, Energy Systems.
    Operating experience and energy system analysis of the biogas-powered 5 kW SOFC system in GlashusEtt2008In: Proceedings of the WREC X conference, 2008Conference paper (Refereed)
  • 40.
    Sevencan, Suat
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Guan, Tingting
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Ridell, Bengt
    Fuel cell based cogeneration: Comparison of electricity production cost for Swedish conditions2013In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 38, no 10, p. 3858-3864Article in journal (Refereed)
    Abstract [en]

    A good portion of greenhouse gas emissions is caused by the energy used in the built environment. Emission reduction goals may be achieved by combining cogeneration with fuel cells (PC). This paper investigates electricity production costs for PC based cogeneration systems with recent data for Swedish conditions. The types of FCs that are investigated are proton exchange membrane PC and molten carbonate FC. Based solely on cost, PC based cogeneration systems cannot compete with conventional systems. However, our results show that Molten Carbonate PC based cogeneration systems will be profitable by 2020. To compete with conventional systems, the capital cost, lifetime and efficiency of FCs must be improved. Creation of a reasonably broad market is essential since it will greatly help to reduce capital costs and operation and maintenance (O&M) costs, the dominating parts of the overall costs according to the analysis.

  • 41.
    Sevencan, Suat
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Economic feasibility study of a fuel cell-based combined cooling, heating and power system for a data centre2016In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 111, p. 218-223Article in journal (Refereed)
    Abstract [en]

    The energy use of data centres is increasing as the data storage needs increase. One of the largest items in the energy use of these facilities is cooling. A fuel cell-based combined cooling, heating and power system can efficiently meet such a centre's need for cooling and in the meantime generate enough electricity for the centre and more. In this paper the economic feasibility of a fuel cell-based combined cooling, heating and power system that meets the energy demands of such a facility is investigated using operational data from an existing data centre in Stockholm, Sweden. The results show that although the system is not feasible with current energy prices and technology it may be feasible in the future with the projected changes in energy prices.

  • 42.
    Tingelöf, Thomas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Hedström, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Holmström, Nicklas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    The influence of CO2, CO and air bleed on the current distribution of a polymer electrolyte fuel cell2008In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, no 33, p. 2064-2072Article in journal (Refereed)
    Abstract [en]

    The influence of CO2, CO and air bleed on current distribution was studied during transient operation, and the dynamic response of the fuel cell was evaluated. CO causes significant changes in the current distribution in a polymer electrolyte fuel cell. The current distribution reaches steady state after approximately 60 min following addition of 10 ppm CO to the anode fuel stream. Air bleed may recover the uneven current distribution caused by CO and also the drop in cell voltage due to CO and CO2 poisoning. The recovery of cell performance during air bleed occurs evenly over the electrode surface even when the O-2 partial pressure is far too low to fully recover the CO poisoning. The O-2 supplied to the anode reacts on the anode catalyst and no O-2 was measured at the cell outlet for air bleed levels up to 2.5%.

  • 43.
    Vernersson, Thomas
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Johansson, Kristina
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    On-Board Hydrogen Storage for Fuel Cell Vehicle2001In: Proceedings of the 36th Intersociety Energy Conversion Engineering Conference: Savannah, GA: 29 July 2001 through 2 August 2001, 2001, p. 581-588Conference paper (Refereed)
    Abstract [en]

    Methods for onboard storage of hydrogen were evaluated for use in a fuel cell vehicle. Compressed hydrogen gas and cryogenic liquid hydrogen seem to be the two most viable options. Both these storage options were modelled, for storage of 5 kg hydrogen, to be implemented in an automotive fuel cell system simulation model. Hydrogen discharge was simulated for different values of cell stack operating pressure and temperature, using a constant rate of hydrogen release, and the power requirement for heating of the hydrogen to fuel cell stack operating temperature was calculated. The calculations show that compressed gaseous hydrogen storage requires a heating capacity of 0.72 - 1 kW for stack operating temperatures of 343-368 K. In the case of liquid hydrogen storage, heating demand for vaporisation and heating of the fuel was calculated to between 10 and 13 kW for stack operating temperatures of 343-368 K. The fuel cell stack produces surplus heat that can be used for fuel heating. Calculations show that the heat content of the cooling medium is sufficient to heat the fuel stream to approximately 20 K below stack temperature, with temperature differences in heat exchangers being the limiting factor. The radiator/compartment heating and humidifier will also extract heat from the cooling medium. However, to reach system temperature an auxiliary heat source will be required. This could be in the form of an electrical heater or a hydrogen burner. Also, for liquid hydrogen storage, a power demand arises for maintaining operating pressure inside the storage vessel during hydrogen release. This was calculated to between 13 and 28 W for the fuel cell stack operating conditions simulated, and this power demand can be supplied by directing a stream of released and heated hydrogen through a coil running inside the storage vessel.

  • 44.
    Wallmark, Cecilia
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Alvfors, Per
    KTH, Superseded Departments, Chemical Engineering and Technology.
    A pinch and exergy analysis of the configuration of a stationary polymer electrolyte fuel cell system2004In: Energy-Efficient, Cost-Effective and Environmentally-Sustainable Systems and Processes, Vols 1-3 / [ed] Rivero, R; Monroy, L; Pulido, R; Tsatsaronis, G, MEXICO: INST MEXICANO DEL PETROLEO , 2004, p. 703-715Conference paper (Refereed)
    Abstract [en]

    In this paper, a pinch-based evaluation and a detailed exergy analysis are applied in order to evaluate the configuration of a stationary polymer electrolyte fuel cell system. The low-pressure fuel cell system includes natural gas steam reforming and is designed to supply a building with heat and power. The exergy balance is calculated from the exergy content of the flows in the system, with the condensed water taken into consideration. By introducing the heat supplied from the combustor to the pinch composite curves, the design and evaluation of the heat exchanger network is aided. The convenient presentation obtained of the energy balance and the exergy destruction points out the importance of the different losses within the 23 components in the fuel cell system and will be used as a basis for future research. The analysis makes it clear that the total efficiency of the system configuration is nearly optimised at 98 % LHV (89 % HHV), but that the electrical efficiency is low. To increase the electrical efficiency, the design of the fuel cell stack has to be improved. The only way to increase the thermal efficiency without changing any system parameters is to decrease the return temperature from the heat sink. The modelling work is described in comparison to measured data. The thermodynamic equations, including a methodology for handling condensed water, are attached to the paper.

  • 45.
    Wallmark, Cecilia
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Design of stationary PEFC system configurations to meet heat and power demands2002In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 106, no 02-jan, p. 83-92Article in journal (Refereed)
    Abstract [en]

    This paper presents heat and power efficiencies of a modeled PEFC system and the methods used to create the system configuration. The paper also includes an example of a simulated fuel cell system supplying a building in Sweden with heat and power. The main method used to create an applicable fuel cell system configuration is pinch technology. This technology is used to evaluate and design a heat exchanger a PEFC system working under stationary conditions, in order to find a solution with high heat utilization. The heat exchanger network for network in the system connecting the reformer, the burner, gas cleaning, hot-water storage and the PEFC stack will affect the heat transferred to the hot-water storage and thereby the heating of the building. The fuel, natural gas, is reformed to a hydrogen-rich gas within a slightly pressurized system. The fuel processor investigated is steam reforming, followed by high- and low-temperature shift reactors and preferential oxidation. The system is connected to the electrical grid for backup and peak demands and to a hot-water storage to meet the varying heat demand for the building. The procedure for designing the fuel cell system installation as co-generation system is described, and the system is simulated for a specific building in Sweden during I year. The results show that the fuel cell system in combination with a burner and hotwater storage could supply the building with the required heat without exceeding any of the given limitations. The designed co-generation system will provide the building with most of its power requirements and would further generate income by sale of electricity to the power grid.

  • 46.
    Wallmark, Cecilia
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Technical design and economic evaluation of a stand-alone PEFC system for buildings in Sweden2003In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 118, no 02-jan, p. 358-366Article in journal (Refereed)
    Abstract [en]

    This paper deals with the prerequisites for a stand-alone fuel cell system installed to avoid replacing or upgrading an ageing, distant power grid connection which only supplies a few buildings with their power demands. The importance of sizing the included components in the energy system is presented in economic terms. The size of the fuel cell system and the energy storage system (battery, hot-water storage and hydrogen storage) are discussed in relation to the yearly distribution of the buildings' power demand. The main design idea is to decrease the size of the fuel cell system without making the battery too expensive and that the power requirements are fulfilled over test periods with decided length and power output. The fuel cell system installation is not economically viable for the presented conditions, but in the paper future feasible scenarios are presented. The calculated incomes are shown as a function of the size of the fuel cell system and energy storage, the electricity costs, the fuel costs including transportation, the prices of electricity and heat, and the fuel cell system costs and efficiencies. The main factor in the system's economic performance is the fuel price, which contributes more than half the costs for the fuel cell system-based energy system. The cost of the power grid is also determining for the result, where the distance to the main power grid is the important factor. The evaluation is performed from the utility company's point of view.

  • 47.
    Wallmark, Cecilia
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Enback, Sofia
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Rissanen, Markku
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Integration of the components in a small-scale stationary research PEFC system2006In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 159, no 1, p. 613-625Article in journal (Refereed)
    Abstract [en]

    With the primary aim of studying the integration of the components in a polymer electrolyte fuel cell (PEFC) system, a test facility for research on small-scale stationary PEFC systems has been built at the Royal Institute of Technology in Stockholm. In this paper the PEFC system with control system and measurement equipment is described in detail together with the first experimental data. The research PEFC system has a flexible configuration and allows fuel cell systems from approximately 0.2 to 4 kW(el) to be tested. The main feed is natural gas, but the fuel cell stack can also be run on humidified hydrogen. The main limitation in the system integration is the power mismatch of the fuel cell stack and fuel processor. The paper begins with a literature review of research/test PEFC systems.

  • 48.
    Wikström, Martina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Biogas or electricity as vehicle fuels derived from food waste-the case of stockholm2012In: Proceedings of the 25th International Conference on Efficiency, Cost, Optimization and Simulation of Energy Conversion Systems and Processes, ECOS 2012, Åbo Akademi University Press, 2012, Vol. 5, p. 68-77Conference paper (Refereed)
    Abstract [en]

    The demand for renewable energy is increasing in Stockholm as well as the rest of the world. Imperative factors, such as the need to reduce anthropogenic green house gas emissions and security of supply, force this development. The European Commission distinguishes the organic compound in municipal solid waste as food waste. Food waste may be digested, form biogas and after upgrading, the biogas may be used as fuel in automotive applications. 

    This study is based on the food waste potential estimations performed by the Stockholm County Administration Board in the County of Stockholm, both in 2009 and in 2030. The County Administration Board aim for this food waste to be converted to the vehicle fuel biogas since this would improve the share of renewable transport fuels and, simultaneously, decrease the green house gas emissions coupled with the degradation of organic material. In 2009, Stockholm generated 122 000 tonnes of food waste which could have been converted to 130 GWh biogas. This amount of biogas corresponds to approximately 15 million litres of petrol. In 2030, the County Administration Board estimates the food waste has increased to 152 000 tonnes, which converted would correspond to 170 GWh biogas. This study will expand the analysis and will consider the option where the biogas from the food waste is use to generate electricity to fuel electric vehicles in Stockholm.  In 2009, no large-scale introduction of electric vehicles in Stockholm had begun but it is vital for decision-makers to assess this option for 2030 in order to obtain a resource and energy efficient Stockholm.

    When considering electricity as vehicle fuel, converting the energy carrier will include additional steps such as electricity generation, distribution, charging of the vehicle as well as the electric powertrain. The overall energy efficiency, from biogas to electric propulsion, is in the order of 40 %. Even though when adding process steps, which imply losses, the more energy efficient energy carrier is electricity. Converting the biogas from the food waste to electricity adds approximately another 10 % of driving distance. Assuming an annual driving distance of 15 000 kilometres, in 2030 this would imply either 27 450 biogas or 30 200 electric passenger cars in the county of Stockholm. The most resource and energy efficient usage of the biogas from food waste would be to convert it to electricity for electric vehicles.

  • 49.
    Wikström, Martina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Sunnerstedt, E.
    Obstacle 1: Capturing the experiences of Swedish electric vehicle users2014In: 2013 World Electric Vehicle Symposium and Exhibition, EVS 2014, 2014Conference paper (Refereed)
    Abstract [en]

    The Swedish National Procurement of Electric Vehicles and Plug-in Hybrids scheme is a technology procurement project aimed at facilitating a market introduction and market expansion in Sweden. The paper describes the development of the data collection method over the course of the project, with the aim of contributing to more efficient evaluations of demonstration fleets of electric vehicles. Combining multiple sources of data may enable a socio-technical understanding of electric vehicle operations. The methods used for data collection in the project are vehicle logbooks, GPS equipment, questionnaires and interviews. Focus groups have been carried out to validate the socio-technical findings. The paper will describe the method development process and the lessons learned are divided into three categories: avoiding misunderstandings, time-saving measures and increasing engagement.

  • 50.
    Wikström, Martina
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Folkesson, Anders
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Analysis of the fuel economy improvement potential of ethanol hybrid buses2011In: Proceedings of the 24th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2011, Nis University , 2011, p. 2220-2229Conference paper (Refereed)
    Abstract [en]

    With the ambitions to further increase its share of renewable fuels and to reduce the amount of carbon dioxide emissions, local emissions and noise, Stockholm Public Transport (SL) hosted a one-year project to evaluate the performance of ethanol hybrid buses. An important part of the project was the duty cycle tests according to SORT - Standardised On-Road Tests cycles (developed by the International Association of Public Transport, UITP). The duty cycle tests generated experimental data, on which this paper’s discussion is based upon. The purpose of this article is to evaluate the potential of energy-efficiency improving measures on the powertrain. The ethanol hybrid bus is a series hybrid vehicle with regenerative braking. A start/stop software to avoid idling was optional. A bus with similar exterior properties, but with the ethanol internal combustion engine coupled to a conventional automatic gearbox instead of a hybrid powertrain was used as a reference throughout the project. Based on both experimental data and simulations, several measures to increase the overall energy-efficiency may be proposed. Assessed measures to increase the energy-efficiency include size optimization of powertrain components, such as energy storage and electric motor, and internal combustion engine (identified by using Sankey diagrams), adjustment of the super capacitors energy management system and utilisation of engine start/stop functionality. Analysis shows that the size of the energy storage is well attuned if applied as urban transport. It would be possible to downsize the ICE, from approximately 200 kW to approximately 150 kW, without losing substantial performance. Using the start/stop software reduces the fuel consumption with 15 % in the standardized city duty cycle but has the potential for even further fuel economy improvements in real traffic with more idling.

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