| 1. |
- Grahn, Maria, 1963, et al.
(författare)
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Biomass for heat or as transportation fuel? - a comparison between two model based studies
- 2007
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Ingår i: Biomass & Bioenergy. ; 31, s. 747-758
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Tidskriftsartikel (refereegranskat)abstract
- In two different energy economy models of the global energy system, the cost-effective use of biomass under a stringent carbon constraint has been analyzed. Gielen et al. conclude that it is cost-effective to use biofuels for transportation, whereas Azar et al. find that it is more cost-effective to use most of the biomass to generate heat and process heat, despite the fact that assumptions about the cost of biofuels production is similar in the models. In this study, we compare the two models with the purpose of finding an explanation for these different results. It was found that both models suggest that biomass is most cost-effectively used for heat production for low carbon taxes (below 50–100 USD/tC, depending on the year in question). But for higher carbon taxes, the cost-effective choice reverses in the BEAP model, but not in the GET model. The reason for this is that GET includes hydrogen from carbon-free energy sources as a technology option, whereas that option is not allowed in the BEAP model. In all other sectors, both models include carbon-free options above biomass. Thus, with higher carbon taxes, biomass will eventually become the cost-effective choice in the transportation sector in BEAP, regardless of its technology cost parameters.
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| 2. |
- Grahn, Maria, 1963, et al.
(författare)
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BIOMASS FOR HEAT OR AS TRANSPORTATION FUEL? A COMPARISON BETWEEN TWO MODEL BASED STUDIES
- 2005
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Ingår i: The 14th European Conference and Technology Exhibition on Biomass for Energy, Industry and Climate in Paris, 17-21 October.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In two different energy economy models of the global energy system, the cost-effective use of biomass under a stringent carbon constraint has been analyzed. Gielen et al. conclude that it is cost-effective to use biofuels for transportation, whereas Azar et al. find that it is more cost-effective to use most of the biomass to generate heat and process heat, despite the fact that assumptions about the cost of biofuels production is rather similar in the models. In this study, we compare the two models with the purpose to find an explanation for these different results. It is found that both models suggest that biomass is most cost-effectively used for heat production for low carbon taxes (below 50-100 USD/tC, depending on the year in question). But for higher carbon taxes the cost effective choice reverses in the BEAP model, but not in the GET model. The reason for that is that GET includes hydrogen from carbon free energy sources as a technology option, whereas that option is not allowed in the BEAP model. In allother sectors, both models include carbon free options above biomass. Thus with higher carbon taxes, biomass will eventually become the cost-effective choice in the transportation sector in BEAP, regardless of its technology cost parameters.
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| 3. |
- Grahn, Maria, 1963, et al.
(författare)
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Cost-effective choices of marine fuels under stringent carbon dioxide targets
- 2013
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Ingår i: Proceedings of 3rd International conference on technologies, operations, logistics and modelling in Low Carbon Shipping, University College London..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In order to investigate cost-effective choices of future marine fuels in a carbon constrained world, the linear optimisation model of the global energy system, GET-RC 6.1, has been modified to GET-RC 6.2, including a more detailed representation of the shipping sector. In this study the GET-RC 6.2 model was used to assess what fuel/fuels and propulsion technology options for shipping are cost-effective to switch to when achieving global stabilisation of atmospheric CO2 concentrations at 400 ppm. The aim is to investigate (i) when is it cost-effective to start to phase out the oil from the shipping sector and what determines the speed of the phase out, (ii) under what circumstances are LNG or methanol cost-effective replacers and (iii) the role of bioenergy as a marine fuel. In our base analysis we analyse results from assuming that CCS will be large-scale available in future as well as if it will not. In the sensitivity analysis different parameters have been varied in order to investigate which impact for example different supply of primary energy sources and different costs for different transportation technologies will have on the choice of fuels in the shipping sector. Three main conclusions are presented (i) it seems to be cost-effective to start to phase out the oil from the shipping sector nearest decades, (ii) natural gas based fuels, i.e. fossil methanol and LNG are the two most probable replacers, of which methanol has been shown to dominate in the case with CCS (methanol or LNG depends on the availability of natural gas, on the methane slip and on infrastructure costs) and (iii) limited supply and competition for bioenergy among other end use sectors makes the contribution of bioenergy small, in the shipping sector.
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| 4. |
- Grahn, Maria, 1963
(författare)
-
Cost-effective fuel and technology choices in the transportation sector in a future carbon constrained world: Results from the Global Energy Transition (GET) model
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis analyzes future fuel and technology choices focusing on transport in a carbon constrained world. The analysis tool used in all five appended papers is the cost-minimizing Global Energy Transition (GET) model. Paper I analyzes cost-effective fuel and technology choices for passenger vehicles under a variety of vehicle cost-assumptions and how these choices depend on technology paths in the electricity sector. We find that cost estimates as well as the availability of carbon capture and storage technology and concentrating solar power have a substantial impact, ranging from a dominance of hydrogen to a dominance of electricity. Paper II analyzes the cost-effectiveness of biofuels for transportation, assuming that industrialized regions start reducing their CO2 emissions some decades ahead of developing regions. We find that biofuels may play a more important role for transportation in industrialized regions if these regions assume their responsibilities and reduce emissions before developing regions start reducing theirs, compared to the case in which all countries take action under a global cap and trade emissions reduction regime. Paper III analyzes how policy instruments aimed at increasing the use of biofuels for transportation in industrialized regions affect CO2 emissions in industrialized and developing regions. We find that such policy instruments may lead to avoided emissions in industrialized regions, especially during the first 50 years, and in a few specific cases in the developing regions, too. However, in the majority of cases, such a biofuels policy leads to increased emissions in the developing regions, i.e., to “carbon leakage.” Paper IV analyzes why two global energy systems models reach different results on the cost-effectiveness of biofuels, although the models have strong similarities. We find biomass most cost-effectively used for heat production at low CO2 taxes in both models. Biomass allocation at higher CO2 taxes may depend on whether CO2-neutral hydrogen and/or electricity are assumed available for the transportation sector at sufficiently low cost. Paper V investigates prices and costs in the GET model, and how these change over time, to get a deeper understanding of why biofuels generally are not a cost-effective transportation fuel choice in the model. We compare the total cost per km for each fuel choice, based on the primary energy prices and carbon tax generated by the model. We find that the required carbon tax level for biofuels to become cost-effective, compared to fossil-based fuels, is a “moving target.” The required tax level increases with an increase in carbon taxes, since the latter increases the price of biomass energy in the model.
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| 5. |
- Grahn, Maria, 1963, et al.
(författare)
-
Cost effective fuel choices in the transportation sector under different international climate regimes – results from a regionalized version of the global energy transition model, GET-R
- 2007
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Ingår i: Proceedings Book of 15th European Biomass Conference and Exhibition from Research to Market Deployment, Industry and Climate, Berlin, Germany, 7-11 May.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- ABSTRACT: The aim of this study is to analyze cost-effective fuel choices in the transportation sector, given that the industrialized regions take the lead in mitigating global warming. The analysis is carried out with a regionalized version of the global energy transition model, GET-R 6.0. It is a linear programming model and it has three end-use sectors: electricity, heat and transportation fuels. It is set up to generate the energy supply mix that meets exogenously given energy demands and carbon constraints at the lowest global energy system cost under different international climate regimes. Two different CO2 reduction scenarios are applied, both meeting an atmospheric CO2 concentration target of 450 ppm by the year 2100. In the first scenario, global CO2 emissions trading are allowed. In the second scenario, it is assumed that emission reductions are not tradable across regions and that the industrialized regions take the lead in mitigating global warming. They start to reduce their CO2 emissions from 2010 while developing regions wait several decades. In this second scenario CO2 emissions are assumed to meet an equal per capita distribution of 1.0 tC/capita, in all six regions, in 2050 and then jointly follow an emission reduction path, towards 0.17 tC/capita (equal to a global emission of 2 GtC) in 2100. The results show that biofuels for transport in industrialized regions reach a mean value of 16% of the total fuel use over this century in the second scenario compared to less than half of that, 6%, in the first scenario.
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| 6. |
- Grahn, Maria, 1963
(författare)
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Cost-effective fuel choices in the transportation sector under stringent CO2-emission reduction targets - Global energy systems modelling
- 2006
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis analyzes the worlds future energy supply in general, and cost-effective fuel choices in the transportation sector in particular, under stringent CO2 constraints. The analysis is carried out with the help of a global energy systems model (GET), developed and modified specifically for each project. GET is a linear programming model and it has three end-use sectors: electricity, heat and transportation fuel. It is set up to generate the energy supply mix that would meet exogenously given energy demand levels at the lowest global cost. This thesis consists of the following three papers (i) an analysis of why two similar global energy systems models, GET and BEAP, give different results as to whether biofuels will become cost-effective in the transportation sector, (ii) an analysis of cost effective fuel choices in a regionalized version of the GET model and (iii) an analysis of the cost dynamics in the GET model in a further developed version of the model. Conclusions drawn within the scope of this thesis are that biomass is most cost-effectively used for heat production at low CO2 taxes, up to about 75 USD/tC, as shown in both the GET and the BEAP model. The sector in which biomass is most cost-effectively used at higher CO2 taxes depends on assumed possible energy carriers and technologies. If hydrogen and/or electricity derived from carbon free energy sources will not be available in the transportation sector at sufficiently low costs, biofuels become an important option if low or zero carbon emissions are to be achieved. Thus, the long run future for the cost-effective transportation fuel choice is still in the open. Regionalizing the GET 1.0 model will not affect the overall pattern of transportation fuel choices, i.e. that gasoline/diesel remain for some decades in the transportation sector until the carbon constraint becomes increasingly stringent and that solar based hydrogen dominates by the end of this century. In paper III, we find that the required carbon tax level where biofuels become cost-efficient, compared to fossil based fuels, is evasive. The tax level moves upwards with increasing carbon taxes, since this leads to an increasing biomass primary energy price in the model.
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| 7. |
- Grahn, Maria, 1963, et al.
(författare)
-
Cost-effective use of biomass - A comparison between two model based studies
- 2006
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Ingår i: Book of Proceedings, RIO6, World Climate and Energy Event, Nov 17-18, 2006, Hotel Othon Palace, Rio de Janeiro, Brazil. - 8590271048 ; , s. 149-153
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In two different energy economy models of the global energy system, the cost-effective use of biomass under a stringent carbon constraint has been analyzed. Gielen et al. conclude that it is cost-effective to use biofuels for transportation, whereas Azar et al. find that it is more cost-effective to use most of the biomass to generate heat and process heat, despite the fact that assumptions about the cost of biofuels production is rather similar in the models. In this study, we compare the two models with the purpose to find an explanation for these different results. It is found that both models suggest that biomass is most cost-effectively used for heat production for low carbon taxes (below 50-100 USD/tC, depending on the year in question). But for higher carbon taxes the cost effective choice reverses in the BEAP model, but not in the GET model. The reason for that is that GET includes hydrogen from carbon free energy sources as a technology option, whereas that option is not allowed in the BEAP model. In all other sectors, both models include carbon free options above biomass. Thus with higher carbon taxes, biomass will eventually become the cost-effective choice in the transportation sector in BEAP, regardless of its technology cost parameters.
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| 8. |
- Grahn, Maria, 1963, et al.
(författare)
-
Cost-effective vehicle and fuel technology choices in a carbon constrained world: insights from global energy systems modelling
- 2010
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Ingår i: Electric and Hybrid Vehicles: Power Sources, Models, Sustainability, Infrastructure and the Market. Editor: Gianfranco Pistoia, Elsevier. ISBN: 798-0-444-53565-8. ; , s. 91-110
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- There is no abstract to this Elsevier book chapter. Here is instead our Discussion/Conclusion chapter: The goal of this work was to investigate the factors influencing the cost-effective vehicle and fuel technology choices in a carbon constrained world. We approached this goal by further developing an existing global energy systems model with the most important addition being a more detailed description of light-duty vehicle technologies (GET RC 6.1). The model is not intended to provide a forecast of the future, but it does provide insight into the system behavior. We have shown how CCS and CSP, technological options that have the potential to significantly reduce CO2 emissions associated with electricity and heat generation, may affect cost-effective fuel and vehicle technologies for transport. We find that the availability of CCS and CSP have substantial impacts on the fuel and technology options for passenger vehicles in meeting global CO2 emission target of 450 ppm at lowest system cost. Four key findings emerge.First, the introduction of CCS increases, in general, the use of coal (in the energy system) and ICEV (for transport). By providing relatively low-cost approaches to reducing CO2 emissions associated with electricity and heat generation, CCS reduces the “CO2 task” for the transportation sector, extends the time span of conventional petroleum-fueled ICEVs, and enables the use of liquid biofuels as well as GTL/CTL for transportation. Second, the introduction of CSP reduces the relative cost of electricity in relation to hydrogen and tends to increase the use of electricity for transport (at the expense of hydrogen).Third, the combined introduction of both CCS and CSP reduces the cost-effectiveness of shifting away from petroleum and ICEVs for a prolonged period of time (e.g., compare the results in Figure X.2D with those in Figure X.2A). Advanced energy technologies (CCS and CSP) reduce the cost of carbon mitigation (in the model) and therefore the incentives to shift to more advanced vehicle technologies. Fourth, the cost estimates for future vehicle technologies are very uncertain (for the time span considered) and therefore it is too early to express firm opinions about the future cost-effectiveness or optimality of different fuel and powertrain combinations. Sensitivity analyses in which these parameters were varied over reasonable ranges result in large differences in the cost-effective fuel and vehicle technology solutions. For instance, for low battery costs ($150/kWh) electrified powertrains dominate and for higher battery costs ($450/kWh) hydrogen-fueled vehicles dominate, regardless of CCS and CSP availability. Thus, our results summarized above should not be interpreted to mean that the electricity production options alone will have a decisive impact on the cost-effective fuel and vehicle options chosen.General results on cost-effective primary energy choices include observations that the use of coal increases substantially when CCS is available and that the use of solar energy (mainly solar-based hydrogen) increases when neither CCS nor CSP are available.Our findings have several policy and research implications. From a policy perspective, the findings highlight the need to recognize, and account for, the interaction between sectors (e.g., that illustrated by the impact of CCS availability in the present work) in policy development. From a research perspective, the findings illustrate the importance of pursuing the research and development of multiple fuel and vehicle technology pathways to achieve the desired result of affordable and sustainable personal mobility.
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| 9. |
- Grahn, Maria, 1963, et al.
(författare)
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Description of the global energy systems model GET-RC 6.1
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- To provide a tool for decision makers to understand meeting global energy demand with global energy supply at a minimum cost and in a sustainable way, we have developed a global energy model (GET-RC 6.1) that includes a detailed description of passenger vehicle technology options. The model can be used to better understand the fuel and vehicle technology choices available for passenger vehicles and how these fit into the larger global energy system, where different energy sectors compete for the same limited primary energy sources. The original linear programming Global Energy Transition (GET) model is designed to meet exogenously given energy demand levels, subject to a CO2 constraint, at the lowest global energy system cost (all costs are in US$). The GET model is being developed and extended to address research questions related to the sustainable development of the global energy system. Several different versions of the GET model are available. The aim of this report is to describe the version used in collaboration between staff at Ford Motor Company and Chalmers University of Technology during the period 2008-2013. The model version used, GET-RC 6.1, was developed to address research questions related to light duty passenger vehicles, where R stands for regionalized and C for cars. The report contains a description of the settings that are defined in the model (i.e., the sets, parameters and variables), the equations used in the model, suggestion for how to implement the model step by step, and the mathematical description of the model.
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| 10. |
- Grahn, Maria, 1963, et al.
(författare)
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Fuel and Vehicle Technology Choices for Passenger Vehicles in Achieving Stringent CO2 Targets: Connections between Transportation and Other Energy Sectors
- 2009
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Ingår i: Environmental Science and Technology. - 1382-3124. ; 43:9, s. 3365-3371
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Tidskriftsartikel (refereegranskat)abstract
- The regionalized Global Energy Transition (GET-R 6.0) modelhas been modified to include a detailed description of light-duty vehicle options and used to investigate the potential impact of carbon capture and storage (CCS) and concentrating solar power (CSP) on cost-effective fuel/vehicle technologies in a carbon-constrained world. Total CO2 emissions were constrained to achieve stabilization at 400-550 ppm, by 2100, at lowest total system cost. The dominant fuel/vehicle technologies varied significantly depending on CO2 constraint, future cost of vehicle technologies, and availability of CCS and CSP. For many cases, no one technology dominated on a global scale. CCS provides relatively inexpensive low-CO2 electricity and heat which prolongs the use of traditional ICEVs. CSP displaces fossil fuel derived electricity, prolongs the use of traditional ICEVs, and promotes electrification of passenger vehicles. In all cases considered, CCS and CSP availability had a major impact on the lowest cost fuel/vehicle technologies, and alternative fuels are needed in response to expected dwindling oil and natural gas supply potential by the end of the century.
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