What Future for Electrofuels in Transport? Analysis of Cost Competitiveness in Global Climate Mitigation

The transport sector is often seen
as the most difficult sector
to decarbonize. In recent years, so-called electrofuels have been
proposed as one option for reducing emissions. Electrofuelshere
defined as fuels made from electricity, water, and carbon dioxidecan
potentially help manage variations in electricity production, reduce
the need for biofuels in the transportation sector while utilizing
current infrastructure, and be of use in sectors where fuel switching
is difficult, such as shipping. We investigate the cost-effectiveness
of electrofuels from an energy system perspective under a climate
mitigation constraint (either 450 or 550 ppm of CO2 in
2100), and we find the following: (i) Electrofuels are unlikely to
become cost-effective unless options for storing carbon are very limited;
in the most favorable case modeledan energy system without
carbon storage and with the more stringent constraint on carbon dioxide
emissionsthey provide approximately 30 EJ globally in 2070
or approximately 15% of the energy demand from transport. (ii) The
cost of the electrolyzer and increased availability of variable renewables
appear not to be key factors in whether electrofuels enter the transport
system, in contrast to findings in previous studies.