Cost-effective sustainable aviation fuel: Insights from a techno-economic and logistics analysis

Sustainable aviation fuels (SAF)s, the key decarbonisation measure of the aviation industry, can be produced from various feedstocks which can be converted by competing technologies. This study critically evaluates the techno-economics and potential carbon-emission reductions of various feedstock-technology combinations and supply chain configurations for SAF production. Feedstocks analysed included tobacco seed (Solaris), A-molasses, industrial off-gases and woody invasive alien plants (IAP)s; the technologies assessed were hydroprocessed esters and fatty acids, alcohol-to-jet and Fischer-Tropsch processing. First generation SAF production using A-molasses was most cost-effective at 1.87–2.05 $/L of SAF and was comparable to international SAF prices when retail and wholesale margins for fuel in South Africa were applied. The results also show that second generation SAF produced via Fischer-Tropsch processing could be cost competitive with first generation SAF (2.00 – $2.25/L) if a novel supply-chain configuration is used which involves several small-scale gasification and Fischer-Tropsch plants linked to a large, centralised refinery. The study demonstrates that supplemental supply of hydrogen to the Fischer-Tropsch synthesis can increase SAF yields by up to 70 % and decrease production costs by as much as 18 %. This transformational integration could increase the SAF output and contribute to carbon emission reductions if the hydrogen is from a renewable source. Additionally, the study demonstrates that applying green premiums on refinery co-products can contribute to reduction in SAF production costs. Therefore, this study provides a critical techno-economic and environmental performance benchmark to aid the development of future SAF projects based on feedstocks similar to those considered in this work.