One or two non-fossil technologies in the decarbonized transport sector?

What factors determine whether policymakers should promote one or more technologies in a decarbonized road transport sector, and what policies should governments choose? We investigate these questions theoretically and numerically through a static, partial equilibrium model for the road transport market. We find that one important factor is how close substitutes the two vehicle technologies are. Further, the number of vehicles of one technology depends on the number of vehicles of the other technology, both in the market and in the first-best solution. The first-best policy involves a subsidy of the markup on charging and filling, where the markup is higher the more utility increases with the number of stations. However, as there are several possible market equilibria, additional policies may be needed to avoid an unwanted lock-in.