Hydroprocessing of fossil fuel-based aviation kerosene – Technology options and climate impact mitigation potentials

Aviation contributes about 4 % of global anthropogenic climate forcing primarily by contrails, CO₂ and NO_x emissions. Renewably sourced aviation kerosene can help to reduce the climate impact from CO₂ and from contrails, but so far, its production capacities are very small. Hence, the climate impact of using fossil fuel-based kerosene with a hydrogen content increased by hydroprocessing as short term mitigation measure is studied here. Therefore, the change in net energy forcing (ΔEF_net) in 2019 is calculated as the sum of the change in contrail energy forcing (ΔEF_contrail) and additional CO₂ emissions (ΔEF_{hydroprocessing}) from aviation kerosene hydroprocessing (ΔEF_net = ΔEF_contrail + ΔEF_{hydroprocessing}). The results show that hydroprocessed aviation kerosene can reduce the net energy forcing EF_net by about 33 % with ΔEF_{hydroprocessing} penalty of 5 %-points. Increasing the hydroprocessing severity increases the relative climate benefit, which is only slightly affected by the emissions factor for hydroprocessing or the choice of the time horizon. Data limitations about fuel composition and its effect on contrails and climate cause considerable uncertainties and the fuel's compliance with specification standards needs consideration. This study on the climate effect of hydroprocessed fossil kerosene can help to assess near-term measures to reduce the climate impact from aviation.