Fuel and Vehicle Technology Choices for Passenger Vehicles in a Sustainable World

The multi-sector regionalized Global Energy Transition (GET-RC 6.1) model covers the global energy system and is designed to meet exogenously-given energy demand levels while stabilizing at a specific atmospheric CO2 concentration at the lowest system cost. Energy demand is aggregated into three sectors: (i) electricity, (ii) transportation, and (iii) "heat" which comprises all stationary uses of energy (industry, commercial, residential) except those associated with providing electricity or transportation fuels. The model includes passenger and freight transportation by air, road, rail, and water. We have updated the model to include a detailed description of fuel and vehicle technologies for passenger vehicles. Five fuel options (petroleum, natural gas, synthetic fuels [coal to liquid, CTL; gas to liquid, GTL; biomass to liquid, BTL], electricity, and hydrogen) were considered. Five vehicle powertrain technologies (internal combustion engine vehicles [ICEVs], hybrid electric vehicles [HEVs], plug-in hybrid electric vehicles [PHEVs], battery electric vehicles [BEVs], and fuel cell vehicles [FCVs]) were included. Carbon capture and storage (CCS) and concentrating solar power (CSP) were available in the model as examples of low-CO2 electricity and/or hydrogen technologies. Passenger vehicle technology and fuel choices consistent with stabilization of atmospheric CO2 at 400-550 ppm by 2100 at the lowest total system cost were investigated.

With regard to passenger vehicle technology, three key findings emerged from the model results. First, recognition of the future connections between transportation and the other energy sectors is very important. Addressing climate change in a cost-effective manner requires a multi-sector perspective. Second, there is no silver bullet; given current uncertainties in future costs/efficiencies there is no clear fuel/vehicle technology winner. In many cases there was no single technology that dominated on a global scale. Third, alternative fuels are needed in response to expected dwindling oil and natural gas supply potential by the end of the century.