Prospective Life Cycle Assessment of Sustainable Aviation Fuel Systems

Sustainable aviation fuels (SAFs) are critical for reducing the greenhouse gas emissions of aviation. However, many SAF feedstocks and biorefining technologies are still in the research and development stages, which complicates accurate predictions of their long-term environmental impacts through traditional life cycle assessments (LCAs). Prospective LCA (pLCA) methods, which use dynamic life cycle inventory models, offer a solution to static LCA by evaluating impacts within a future context. This study leverages pLCA to assess the decarbonization potential of three SAF pathways using corn, miscanthus, and algae biomass across three future scenarios. The miscanthus pathway consistently demonstrates the lowest carbon intensity, starting at approximately 14 g CO₂e MJ^-1 and maintaining this low level across all scenarios by 2050. This stability is attributed to its simpler and more mature conversion technology. In contrast, the algal and corn pathways, which initially present higher emissions (98.1 g CO₂e MJ^-1 and 71.8 g CO₂e MJ^-1 respectively), show significant reductions by 2050. Specifically, algal and corn-based SAF drop to 33.1 g CO₂e MJ^-1 and 49 g CO₂e MJ^-1, respectively, particularly under aggressive climate policy scenarios. These findings highlight the importance of pLCA for evaluating emerging technologies, as results are shown to significantly change from 2020 to 2050.