A comparison between renewable transport fuels that can supplement or replace biofuels in a 100% renewable energy system

Identifying renewable energy alternatives in transport is particularly complicated, since the end-user can vary from a single-person car to a cargo ship. The aim of this paper is to aid this process by comparing 7 different methods for producing transport fuels in terms of the resources required, the conversion processes used, the fuel obtained, and the transport demand met. The results indicate that electricity should be prioritised as a transport fuel in the future since it is the most efficient and cheapest pathway. However, since electricity is not suitable for all modes of transport, some form of energy dense fuel is also necessary. The results in this paper suggest that this fuel will be produced by hydrogenating either biomass or carbon dioxide, depending on the residual biomass available. Biomass gasification, steam electrolysis, and carbon capture are key technologies in the future for these fuels. Based on the assumptions in this study, some of the renewable fuels proposed here would be cheaper than oil in the year 2050. However, this is based on fuel production costs only and does do not consider other key costs, such as the infrastructure costs, which will be considered in the future research.