In this new journal article published in Energy Policy, we quantify the degree to which biomass- and waste-derived alternative jet fuels (AJF) could contribute to global aviation CO2 reductions by 2050, by assessing: the availability of feedstock; AJF volumes that could be produced from that feedstock; the lifecycle emissions of AJF compared to petroleum-derived fuel; and the number of bio-refineries and capital investment required to achieve the calculated emissions reductions. The paper finds that the use of AJF could reduce aviation's lifecycle GHG emissions in 2050 by a maximum of approximately two thirds, but that this would require: prices or policies significantly incentivizing feedstock production; and that AJF production is prioritized over other potential uses of these resources. Reductions of even 15% by 2050 would require construction of ~60 new bio-refineries annually (similar to growth in global biofuel refinery capacity in the early 2000s), and capital investment of ~12 billion USD per year (~1/5 annual capital investment in petroleum refining).
This work has been used to inform global regulation for international aviation at the International Civil Aviation Organization, specifically on the expected contribution of alternative fuels to meet binding international aviation CO2 emissions reductions agreed to under the CORSIA system.