| 1. |
- Ahlgren, Erik, 1962, et al.
(författare)
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Biokombi Rya - slutrapporter från ingående delprojekt
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Inom projektet Biokombi Rya har ett flertal olika forskargrupper samarbetat för att studera system¬effekterna av förgasning av biobränsle ur olika aspekter. Syftet med projektet är att öka kunskapen om biobränsleförgasning i Sverige samt att utreda förutsättningar för att sådana anläggningar ska vara ekonomiskt och miljömässigt intressanta. En referensgrupp har varit kopplad till projektet där förutsättningar, resultat och slutsatser har behandlats.I denna underlagsrapport har slutrapporterna från projektets delprojekt samlats. De beskriver förutsättningar, metodansatser, använda data och resultat utförligt och utgör på så sätt ett viktigt komplement till den mer övergripande beskrivningen i projektets syntesrapport. De delrapporter som ingår har valts för att täcka in samtliga delar av projektet som är av allmänt intresse. Projektresultat som publicerats på annat sätt berörs dock mer kortfattat.Projektet Biokombi Rya har pågått under två år (2005-2006) och drivits av Chalmers EnergiCentrum. Förutom de omfattande analysinsatser som författarna till denna rapport står för, har Avdelningen för kemisk teknologi vid KTH, Siemens Industrial Turbines AB och Göteborg Energi AB bidragit med expertstöd. CIT Industriell Energianalys, med undertecknad som projektledare, har stått för projektledning och koordination.Projektet har finansierats av Energimyndigheten, Göteborg Energis forsknings¬stiftelse samt Göteborg Energi AB.
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| 2. |
- Fahlén, Elsa, 1981, et al.
(författare)
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Accounting for external costs in a study of a Swedish district-heating system - An assessment of environmental policies
- 2010
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Ingår i: Energy Policy. - : Elsevier BV. - 0301-4215. ; 38:9, s. 4909-4920
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Tidskriftsartikel (refereegranskat)abstract
- Sweden has historically had strict emission control by implementation of economic policy instruments with the aim of internalising the external costs of air pollution. This study aims to evaluate how well current Swedish policy instruments reflect the environmental costs associated with heat generation in several district-heating (DH) plants in the DH system of Goteborg. Furthermore, it aims to simulate and evaluate the operation of the DH system based on its social cost-effectiveness which takes into account the DH system's private and external costs (non-internalised environmental costs). The study shows that the economic policy instruments do not fully internalise all external costs whereas for certain technologies, the costs in terms of taxes, emission permits, environmental fees, etc. are higher than the environmental costs caused by the pollutants, given the environmental cost estimates used in the study. The simulation results show that the deviating internalisation of external costs affects the economic ranking of the different plants within the studied DH system. The estimated loss in social-cost effectiveness of the operation of the DH system of Goteborg is noticable but relatively small if compared to the variable heat generation costs for most of the studied DH plants. (C) 2010 Elsevier Ltd. All rights reserved.
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| 3. |
- Fahlén, Elsa, 1981, et al.
(författare)
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Accounting for external environmental costs in a study of a Swedish district-heating system - an assessment of simplified approaches
- 2012
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 27, s. 165-176
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Tidskriftsartikel (refereegranskat)abstract
- External cost (XC) accounting of air pollution has been applied in a number of energy system studies in order to find least-cost solutions from a social-cost perspective. In these studies, the economic evaluation covers the XCs apart from the private costs. The greater number of life cycle processes, pollutants and environmental impacts covered, the more accurate the results will be but, obviously, the XC accounting process will be more complex and time-consuming. There is also the risk of increasing uncertainty as complexity increases, and the question is to decide on the appropriate level of comprehensiveness. The purpose of this paper is to evaluate certain simplified XC accounting approaches applied to a study of the district-heating (DH) system of Gothenburg, Sweden. The methodology applied is to vary the inclusion of pollutants and life cycle processes in the XC accounting under different scenarios. The results show that if environmental costs are estimated to be substantial and the net power generated in the DH system is assumed to replace generation in coal-fuelled power plants, limiting the coverage of life cycle processes and pollutants outside the DH system would not be appropriate. Instead, if assuming that power generation based on natural gas were replaced, the application of all simplified approaches studied leads to DH solutions that are congruent with those obtained employing a more comprehensive approach and is, thus, considered to be sufficient. However, results also show that certain simplified approaches are justified regardless of the assumed power generation replacement and given a wide range of environmental cost estimates used in the study, such as limiting the number of covered pollutants to the most relevant ones (CO2, SO2 and NOx). Thus, a less comprehensive XC accounting process may be considered appropriate for finding least social-cost solutions in the Gothenburg DH system, as well as potentially in many other DH systems featuring similar technical and environmental performance.
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| 4. |
- Fahlén, Elsa, 1981
(författare)
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Assessing District-Heating Sustainability – Case Studies of CO2 Mitigation Strategies and Environmental Cost Accounting
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- District heating (DH) may play an important role in achieving the EU goal of a secure, competitive and sustainable energy supply. Integrated energy solutions based on technologies, such as biomass gasification for transport fuel, electricity and heat production and heat-driven absorption cooling, create new optimisation possibilities through the linkage between heat, power, cooling and transport fuel markets which may reduce the global warming contribution of the energy sector. With increasing focus on climate change impacts of greenhouse gas emissions, the environmental effects of other air pollutants should not be neglected. To achieve both a competitive and a sustainable energy supply, it is necessary to integrate environmental considerations into economic policies. Through accounting for external costs of air pollution in energy system modelling and analysis, sustainability aspects may be integrated into DH assessments.The aim of this thesis is to develop, apply and evaluate methodologies for assessing conventional and new technology solutions in a DH system; the assessments are made from a DH perspective with respect to two factors – cost-effectiveness and environmental impacts – which are either assessed separately or integrated through external cost accounting. Various CO2 mitigation strategies are evaluated with regard to the robustness of the DH system in meeting future developments of energy market prices and policies. The studies are performed using a systems approach by using the simulating DH supply model MARTES as applied to the DH system of Göteborg, Sweden.This thesis concludes that the integration of biomass gasification technology and absorption cooling technology in DH systems has the potential for cost-effective CO2 emission reduction, in line with other EU goals to increase the share of renewable sources in energy use and to increase energy efficiency. Accounting for external costs of not only climate change but also other environmental impacts of air pollution may strongly influence least-cost operations of DH systems, especially in systems that include combined heat and power plants. However, case study results show that effects on cost-effectiveness of annual DH generation are generally minor.Applying life cycle thinking to economic and environmental analyses of energy systems proves to be of great importance to the outcome and reliability of DH assessments. This thesis emphasises the importance of paying attention to environmental impacts of airborne emissions other than CO2, including emissions from upstream processes. As life cycle processes, pollutants and impact categories are covered in external cost accounting to a greater extent, the more accurate the results will be, while the accounting process will be more complex and time-consuming. However, this thesis illustrates that an external cost accounting based on a simplified approach may be as accurate as employing a more comprehensive approach.
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| 5. |
- Fahlén, Elsa, 1981, et al.
(författare)
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Assessment of absorption cooling as a district heating system strategy - A case study
- 2012
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Ingår i: Energy Conversion and Management. - : Elsevier. - 0196-8904 .- 1879-2227. ; 60:SI, s. 115-124
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Tidskriftsartikel (refereegranskat)abstract
- Heat load variations, daily as well as seasonal, are constraining co-generation of high-value energy products as well as excess heat utilisation. Integration of heat-driven absorption cooling (AC) technology in a district heating and cooling (DHC) system raises the district heat (DH) demand during low-demand periods and may thus contribute to a more efficient resource utilisation. In Sweden, AC expansion is a potentially interesting option since the cooling demand is rapidly increasing, albeit from low levels, and DH systems cover most of the areas with potential cooling demand. This study aims to assess the potential for cost and CO2 emission reduction due to expansion of DH-driven AC instead of electricity-driven compression cooling in the DHC system of Goteborg, characterised by a high share of low-cost excess heat sources. The DHC production is simulated on an hourly basis using the least-cost model MARTES. Despite recent advances of compression chillers, the results show potential for cost-effective CO2 emission reduction by AC expansion, which is robust with regards to the different scenarios applied of energy market prices and policies. While the effects on annual DHC system results are minor, the study illustrates that an increased cooling demand may be met by generation associated with low or even negative net CO2 emissions - as long as there is high availability of industrial excess heat in the DHC system, or if e.g. new biomass-based combined heat and power capacity is installed, due to the avoided and replaced marginal power generation.
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| 6. |
- Fahlén, Elsa, 1981
(författare)
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Assessment of existing and potential developments of district-heating systems
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- District heating (DH) may play an important role for achieving the EU goal of a secure, competitive and sustainable energy supply. DH benefits from the possibilities of utilising local resources such as municipal solid waste and other low-quality fuels, as well as low-cost waste heat from industries and from combined heat and power plants (CHP). This may contribute not only to a more competitive energy supply but also to lower environmental impacts due to the avoidance of emissions from other fuels. There is a large diversity of production-mix solutions, especially among, and within the Swedish district-heating systems (DHS). This helps to spread the risks of future availability and price trends of limited energy sources as well as the risks of changes in policy instruments.With increasingly stringent targets for reduction of CO2 emissions and for the share of the energy and transport fuel supply based on renewable energy sources, the pressure on limited biomass resources is expected to increase. This will certainly favour efficiency measures and efficient resource utilisation. Technologies for gasification of biomass may then play a key role given their potential for high electrical efficiency and polygeneration, i.e. combined production of e.g. not only electricity but also bio-derived transport fuels (BTF) and district heat.The air pollution associated with energy use causes different kinds of damage to e.g. human health, ecosystems and buildings. If the damage costs are not included in the market prices and not accounted for in the polluter’s economy, these costs are so-called external costs. To achieve both a competitive and a sustainable energy supply it is necessary to integrate the environmental considerations into energy policy and internalise external costs in energy systems studies.The aim of this thesis is to develop, apply and evaluate methodologies for assessment of existing and potential developments of DHS, considering more efficient resource utilisation with respect to economic, environmental and social aspects. The first appended paper evaluates the economic consequences, and the CO2 reduction potential, of integration of different biomass gasification alternatives in a Swedish DHS. The second appended paper assesses the socio-economic cost-effectiveness of a DHS’s operation which takes external costs into account. A systems modelling approach is applied in the studies and the MARTES model is used, which is a simulating DH supply model, here applied to the DHS of Göteborg.The first paper’s main findings show that the generation of electricity and transport fuel based on renewable energy sources can be significantly increased by integration of biomass gasification technology in the DHS of Göteborg, and that it can lead to cost-effective reduction of global CO2 emissions, given the assumptions of marginal power generation technologies and alternative use of transport fuels. The economic results show that gasified biomass, upgraded to synthetic natural gas, is better used as BTF than for substitution of natural gas in an existing combined cycle CHP plant. The study also stresses the importance of assumptions for the base load options when analysing a system with high availability of waste heat.In the second paper, the socio-economic cost-effectiveness of a DHS’s operation has been assessed by studying the DHS’s total costs which include external costs, referred to as the social system cost. The results show that the studied DHS’s marginal heat production differs due to optimisations regarding external costs or current Swedish policy instruments, and that these differences result in various social system costs and external costs. The results also show that the contribution of CO2 emissions dominates the external costs associated with the DHS’s operation, whereas the local and regional pollutants, in this case SO2 and NOx emissions, have a small impact on the results.
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| 7. |
- Fahlén, Elsa, 1981, et al.
(författare)
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Assessment of integration of different biomass gasification alternatives in a district-heating system
- 2009
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Ingår i: Energy. - 0360-5442 .- 1873-6785. ; 34, s. 2184-2195
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Tidskriftsartikel (refereegranskat)abstract
- With increasingly stringent CO2 emission reduction targets, incentives for efficient use of limited biomass resources increase. Technologies for gasification of biomass may then play a key role given their potential for high electrical efficiency and multiple outputs; not only electricity but also bio transport fuels and district heat. The aim of this study is to assess the economic consequences and the potential for CO2reduction of integration of a biomass gasification plant into a district-heating (DH) system. The study focuses on co-location with an existing natural gas combined cycle heat and power plant in the municipal DH system of Go¨ teborg, Sweden. The analysis is carried out using a systems modeling approach. The so-called MARTES model is used. MARTES is a simulating, DH systems supply model with a detailed time slice division. The economic robustness of different solutions is investigated by using different sets of parameters for electricity price, fuel prices and policy tools. In this study, it is assumed that not only tradable green certificates for electricity but also tradable green certificates for transport fuels exist. The economic results show strong dependence on the technical solutions and scenario assumptions but in most cases a stand-alone SNG-polygeneration plant with district-heat delivery is the cost-optimal solution. Its profitability is strongly dependent on policy tools and the price relation between biomass and fossil fuels. Finally, the results show that operation of the biomass gasification plants reduces the (DH) system’s net emissions of CO2.
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| 8. |
- Fahlén, Elsa, 1981, et al.
(författare)
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Integration of biomass gasification plants in district-heating systems – a systems analysis
- 2007
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Ingår i: Proceedings of ECOS 2007 20th International Conference, Padova, Italy. ; Vol. 1, s. 533-540
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Tidskriftsartikel (refereegranskat)abstract
- With higher targets for CO2 reduction, incentives increase for an efficient use of limited biomass resources. Technologies for gasification of biomass may then play a key role given their potential for high electrical efficiency and multiple outputs; not only electricity but also district heat and transport fuels. The aim of this study is to evaluate the economic consequences of integration of a biomass gasification plant in a district-heating system. The study focuses on co-location with an existing natural gas combined cycle heat and power plant in the municipal district-heating system of Göteborg. The analysis is carried out using a systems modelling approach. The so-called MARTES model is used, which is a simulating, district-heating systems supply model with a detailed time slice division. The results show strongly dependence on the technical solution and the scenario assumptions. For some parameter sets of fuel and electricity prices and policy tools, certain technical solutions for integration of biomass gasification technology in district-heating systems are the cost-optimal solutions.
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| 9. |
- Fahlén, Elsa, 1981, et al.
(författare)
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Internalisation of external costs in studies of local district-heating based energy systems
- 2008
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Ingår i: Proceedings of 11th International Symposium on District Heating and Cooling, Reykjavik, Iceland. ; , s. 233-240
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Konferensbidrag (refereegranskat)abstract
- This study aims to investigate how external costs can be internalised in an energy systems study of local district-heating aiming to assess the socio-economic cost-effectiveness of the district heating system’s operation. It shows that current Swedish energy policy instruments lead to a socio-economic suboptimal operation on the marginal production of heat in the studied district heating system of Göteborg.
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| 10. |
- Fahlén, Elsa, 1981, et al.
(författare)
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Potential CO2 Reduction by Increased Integration of Absorption Cooling in a Swedish District Energy System
- 2011
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Ingår i: Proceedings in: 24th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, Novi Sad, Serbia July 4-7, 2011.
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Konferensbidrag (refereegranskat)abstract
- Comfort cooling demand is increasing also in temperate countries. There, the cooling demand is characterised by strong seasonal as well as daily demand variations. The utilisation of heat-driven absorption chillers instead of conventional electricity-driven compression chillers is decreasing the power used for cooling but this option is mainly of interest where there is low-cost heat available. Thus, within district-heating (DH) systems with large excess heat supplies this might be a particularly attractive solution. In other DH systems this may instead provide the basis for expanded combined heat and power operation. In Sweden, this is a potentially interesting option since cooling demand is rapidly increasing, albeit from low levels, and DH systems cover most of the areas with potential cooling demand. The aim of the study is to analyse the potential CO2 reduction due to increased substitution of compression chillers by DH-driven absorption chillers. The study is a case study using the district heating and cooling (DHC) system of Göteborg, characterised by a high share of industrial and municipal solid waste incineration excess heat. The DHC production is simulated with a detailed time slice division using the least-cost DH supply model MARTES. The heat needed in the absorption chillers is assumed to be supplied by marginally produced DH. The results show that an increased share of absorption cooling capacity can lead to cost-effective CO2 emissions reduction. The simulation results show that the heat used in the absorption chillers mainly is low-cost industrial excess heat. As long as this is available, or if e.g. new biomass-based CHP is installed within the DHC system, an increased cooling demand can be met by generation associated with low net CO2 emissions due to the avoided and replaced marginal power generation.
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