A review of techno-economic analyses and life cycle greenhouse gas emissions of biomass-to-hydrocarbon “drop-in” fuels

Abstract

Synthetic “drop-in” fuels are compatible with existing fuel and vehicle infrastructures and, when produced sustainably, they could play an important role in mitigating the emissions of greenhouse gases (GHG) from transportation, especially in the hard-to-decarbonise sectors like freight and aviation. However, there is a need to understand the availability of biomass resources for drop-in fuel applications and the potential challenges associated with using these feedstocks including the supply chain issues. Hence, this paper offers a critical review of non-food biomass and drop-in fuel production including the biomass availability in the UK, the production of drop-in fuels from biomass feedstocks via thermochemical routes, estimated fuel production prices and volumes, and life cycle GHG impacts. The paper explores several fuel production factors, including energy and hydrogen requirements, as well as supply-chain considerations, which were used to estimate the drop-in fuel potential in the UK economy. We estimate the availability of non-food biomass resources in the UK to be in the range of 167–205 Mtpa (wet) [839–1033 PJ per year], as more than 50 % of these volumes are from high moisture content feedstocks such as biogenic municipal waste and sewage sludge. Other biomass feedstocks that are produced in significant quantities include straw and wood waste. Also, it is estimated that the total UK drop-in fuel manufacturing potential is in the range of 269–563 PJ per year. When used to displace fossil fuels in road transportation, this could lead to a total GHG reduction of 18.7–64.4 Mt. CO2eq per year which is 18.8–64.7 % relative to the UK's overall road transport emissions from all fuels in 2021.