Mitigating carbon emissions through sustainable aviation fuels: costs and potential

In general, the certified pathways for the production of sustainable aviation fuels (SAFs) are still far from being competitive with fossil kerosene, although they have the potential to reduce greenhouse gas (GHG) emissions. However, the mitigation costs related to SAFs and how they compete with the carbon credits market remain unclear. The present study addressed these issues, evaluating SAF pathways based on hydrotreatment (HEFA process) of soybean oil, palm oil, used cooking oil (UCO) and beef tallow; dehydration and oligomerization of ethanol (ATJ technology) obtained from sugarcane, lignocellulosic residues, and steel off-gases; and the thermochemical conversion of lignocellulosic residues using the Fischer-Tropsch (FT) process and hydrothermal liquefaction (HTL). Residue-based pathways had lower mitigation costs. Used cooking oil / HEFA had the lowest value (185 USD tCO(2e)(-1)), followed by the thermochemical conversion of forestry residues (234-263 USD tCO(2e)(-1)). Of the 1G pathways, SAF production from 1G sugarcane ethanol (SC-1G/ATJ) performed better (495 USD tCO(2e)(-1)) than oil-based ones. In comparison with the carbon market, the mitigation costs of SAFs are much higher than the current prices or even future ones. However, several concerns about the credibility of the emission units and their effective mitigation effects indicate that SAFs could play an important role in aviation sector goals. Considering the potential of supplying SAF and mitigating emissions, SC-1G/ATJ was suggested as a preferred alternative in the short term. Of the residue-based pathways, tallow / HEFA and FT of forestry residues are suggested as strategic alternatives. (c) 2020 The Authors. Biofuels, Bioproducts, and Biorefining published by Society of Chemical Industry and John Wiley & Sons, Ltd

Automated summary

In general, certified pathways for sustainable aviation fuels are not yet competitive with fossil kerosene, but certain options such as hydrotreatment of soybean oil, palm oil, used cooking oil, and beef tallow show potential. Among the pathways evaluated, residue-based options have lower mitigation costs, especially compared to 1G ethanol options like sugarcane ethanol. Mitigation costs of SAFs are currently much higher than carbon market prices, but SAFs could still play an important role in achieving aviation sector emissions goals.