We develop a framework for comparing carbon-neutral synthetic fuels (CNSFs) with battery electric vehicles (BEVs) as alternatives to reducing CO2 emissions from light-duty vehicles. CNSFs can be divided into fuels produced from biomass via gasification and electrofuels produced from CO2 and water using electricity. We develop CNSF cost estimates for first-of-a-kind plants operating at commercial scale. Although already competitive over short distances, we find that longer-range BEVs are likely to remain more expensive than CNSFs even if low (∼$125/kWh) battery costs are achieved, and all three options would require carbon prices in excess of $130/tCO2 or oil prices in excess of $100/bbl to become commercially viable relative to petroleum. The viability of electrofuels ultimately depends on access to low-cost, ultra-low-carbon power systems or sources of zero-carbon electricity with high annual availability. Priorities should include deploying a portfolio of CNSF technologies to help appraise decarbonization pathways, economies of scale, and learning by doing.