Biomethane in the transport sector--An appraisal of the forgotten option

The last 20 years efforts to find a long-term and large-scale biofuel alternative to petrol and diesel for the transport sector have been intensified with a focus on liquid biofuels, such as ethanol, methanol and Fischer-Tropsh diesel derived from wood. The large-scale production of biomethane has so far largely been overlooked in comparative studies that focus on the long-term renewable options. The aim of this article fills this gap and to provide a broad and systematic assessment of the future potential of biomethane compared to other biofuels. In order to become a large-scale option, biomethane production from woody biomass via gasification needs to be developed and commercialized. However, biomethane exhibits a clear development path with relatively low financial and technical risks starting with local solutions utilizing wet biomass resources towards medium and eventually large-scale gasification with economics similar to liquid second generation biofuels. The disadvantage of being a gaseous fuel is not insurmountable and can furthermore be relaxed by the integration and dual-use of the existing distribution system for natural gas. This assessment concludes that more emphasize should be given to biomethane as a large-scale option given the opportunity to use woody biomass from gasification.