Flying green: Life cycle assessment and decomposition of bio-based sustainable aviation fuels production in Australia and global benchmarks

Sustainable aviation fuels (SAF) are critical for sustainably transitioning the aviation sector into low-carbon status depending on the type of feedstock and technology. However, studies on the key factors that drive these environmental benefits, and the effect of emerging technologies such as biomanufacturing would have on SAF production in the future are limited. Consequently, we assessed the environmental impact of bio-based SAF production and investigated the key drivers of its carbon footprint (greenhouse gas emissions), focusing on Hydroprocessed Esters and Fatty Acids (HEFA), Alcohol-to-Jet (AtJ), and Fischer-Tropsch (FT) pathways. Using Australia as a case study alongside a global benchmark, this study decomposed the life-cycle carbon footprint of SAF production into carbon intensity, energy efficiency, scalability, cost competitiveness, and industry size factors. Results reveal that the energy efficiency factor significantly reduces the SAF production carbon footprint across all three pathways. The scalability factor was a dominant challenge that greatly influenced the carbon footprint of SAF production across global scenarios, especially for HEFA and AtJ, while for Australia the effects of the scalability factor were smaller though remain a noticeable challenge for AtJ. The decomposition results in Australia resemble mostly the high- and very high- SAF production scenarios globally. Results of a sensitivity analysis suggest that biomanufacturing potentially enhances emission reductions for various SAF feedstocks in both Australia and globally, particularly for oilseed-based pathways in Australia.