Maria Grahn

Climate impact of transportation A model comparison

Transportation contributes to a significant and rising share of global energy use and GHG emissions. Therefore modeling future travel demand, its fuel use, and resulting CO2 emission is highly relevant for climate change mitigation. In this study we compare the baseline projections for global service demand (passenger-kilometers, ton-kilometers), fuel use, and CO2 emissions of five different global transport models using harmonized input assumptions on income and population. For four models we also evaluate the impact of a carbon tax. All models project a steep increase in service demand over the century. Technology change is important for limiting energy consumption and CO2 emissions, the study also shows that in order to stabilise or even decrease emissions radical changes would be required. While all models project liquid fossil fuels dominating up to 2050, they differ regarding the use of alternative fuels (natural gas, hydrogen, biofuels, and electricity), because of different fuel price projections. The carbon tax of 200 USD/tCO2 in 2050 stabilizes or reverses global emission growth in all models. Besides common findings many differences in the model assumptions and projections indicate room for further understanding long-term trends and uncertainty in future transport systems.

Cost-effective choices of marine fuels in a carbon-constrained world: results from a global energy model.

The regionalized Global Energy Transition model has been modified to include a more detailed shipping sector in order to assess what marine fuels and propulsion technologies might be cost-effective by 2050 when achieving an atmospheric CO2 concentration of 400 or 500 ppm by the year 2100. The robustness of the results was examined in a Monte Carlo analysis, varying uncertain parameters and technology options, including the amount of primary energy resources, the availability of carbon capture and storage (CCS) technologies, and costs of different technologies and fuels. The four main findings are (i) it is cost-effective to start the phase out of fuel oil from the shipping sector in the next decade; (ii) natural gas-based fuels (liquefied natural gas and methanol) are the most probable substitutes during the study period; (iii) availability of CCS, the CO2 target, the liquefied natural gas tank cost and potential oil resources affect marine fuel choices significantly; and (iv) biofuels rarely play a major role in the shipping sector, due to limited supply and competition for bioenergy from other energy sectors.

Low-CO2 Electricity and Hydrogen: A Help or Hindrance for Electric and Hydrogen Vehicles?

The title question was addressed using an energy model that accounts for projected global energy use in all sectors (transportation, heat, and power) of the global economy. Global CO(2) emissions were constrained to achieve stabilization at 400-550 ppm by 2100 at the lowest total system cost (equivalent to perfect CO(2) cap-and-trade regime). For future scenarios where vehicle technology costs were sufficiently competitive to advantage either hydrogen or electric vehicles, increased availability of low-cost, low-CO(2) electricity/hydrogen delayed (but did not prevent) the use of electric/hydrogen-powered vehicles in the model. This occurs when low-CO(2) electricity/hydrogen provides more cost-effective CO(2) mitigation opportunities in the heat and power energy sectors than in transportation. Connections between the sectors leading to this counterintuitive result need consideration in policy and technology planning.

Transport biofuels in global energy–economy modelling – a review of comprehensive energy systems assessment approaches

The high oil dependence and the growth of energy use in the transport sector have increased the interest in alternative nonfossil fuels as a measure to mitigate climate change and improve energy security. More ambitious energy and environmental targets and larger use of nonfossil energy in the transport sector increase energy–transport interactions and system effects over sector boundaries. While the stationary energy sector (e.g., electricity and heat generation) and the transport sector earlier to large degree could be considered as separate systems with limited interaction, integrated analysis approaches and assessments of energy–transport interactions now grow in importance. In recent years, the scientific literature has presented an increasing number of global energy–economy future studies based on systems modelling treating the transport sector as an integral part of the overall energy system and/or economy. Many of these studies provide important insights regarding transport biofuels. To clarify similarities and differences in approaches and results, the present work reviews studies on transport biofuels in global energy–economy modelling and investigates what future role comprehensive global energy–economy modelling studies portray for transport biofuels in terms of their potential and competitiveness. The results vary widely between the studies, but the resulting transport biofuel market shares are mainly below 40% during the entire time periods analysed. Some of the reviewed studies show higher transport biofuel market shares in the medium (15–30 years) than in the long term (above 30 years), and, in the long‐term models, at the end of the modelling horizon, transport biofuels are often substituted by electric and hydrogen cars.

CHAPTER FOUR – Cost-Effective Vehicle and Fuel Technology Choices in a Carbon-Constrained World: Insights from Global Energy Systems Modeling

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 (

Cost-effective vehicle and fuel technology choices in a carbon constrained world: insights from global energy systems modelling

150/kWh) electrified powertrains dominate and for higher battery costs (

The potential for electrofuels production in Sweden utilizing fossil and biogenic CO2 point sources

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.

Sustainable Mobility: Insights from a Global Energy Model

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 (

A COMPARATIVE ASSESSMENT OF CURRENT AND FUTURE FUELS FOR THE TRANSPORT SECTOR

150/kWh) electrified powertrains dominate and for higher battery costs (

Workshop Report: Nordic Action for a Transformation to Low-carbon Shipping

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.