Turning Challenge into Opportunity 2025

Aviation Technology Technology description Technology readiness level (TRL)TRL rationale Use cases Use case source(s) Alcohol-to-jet synthetic paraffinic kerosene (ATJ-SPK)Conversion of cellulosic or starchy alcohols (isobutanol and ethanol) into a drop-in fuel occurs through a series of chemical reactions – dehydration, hydrogenation, oligomerization and hydrotreatment. The alcohols are derived from cellulosic or starchy feedstocks via fermentation or gasification. Ethanol and isobutanol produced from lignocellulosic biomass (such as corn stover) are considered favourable feedstocks, although other potential sources (not yet approved by American Society for Testing and Minerals (ASTM)) include methanol, iso-propanol and long-chain fatty alcohols. ASTM approval was granted in April 2016 for isobutanol and in June 2018 for ethanol with a 30% blend limit.7-8 IEA, 2025. ETP Clean Energy Technology GuideLanzaJet is a leading player in the ATJ technology space. Renowned for its proprietary processes that convert various low-carbon alcohols – including ethanol and isobutanol – into SAF, LanzaJet’s Freedom Pines facility in Georgia, USA, is set to become the first small- scale commercial ATJ plant. The company participates in multiple projects worldwide, such as the LanzaTech DRAGON SAF project in the UK and Project Ulysses in Australia.IEA Bioenergy, 2024. Progress in commercialisation of biojet/sustainable aviation fuels (SAF) Catalytic hydrothermolysis synthesized keroseneAlso known as hydrothermal liquefaction (HTL), this process combines clean free fatty acid oil from processing waste oils or energy oils with preheated feed water, which is then passed through a catalytic hydrothermolysis reactor. Feedstocks for the CH-SPK process include a range of triglyceride-based materials, such as soybean oil, jatropha oil, camelina oil, carinata oil and tung oil. ASTM approval was given in February 2020 with a 50% blend limit.4-5 IEA, 2025. ETP Clean Energy Technology GuideProject Firefly (Firefly Green Fuels, UK) intends to convert treated human sewage (biosolids) into SAF using HTL, producing biocrude that is subsequently hydroprocessed to jet fuel. A pilot project is planned for Haltermann Carless’s Harwich refinery in Essex. Applied Research Associates (ARA) developed the Biofuels ISOCONVERSION (BIC) process, which utilizes catalytic hydrothermolysis to produce sustainable fuels. They have partnered with Chevron Lummus Global (CLG) to further develop and commercialize the BIC process.Firefly Green Fuels, 2024. Significant progress made towards commercialisation Advanced Biofuels USA, 2020. ASTM approves ARA’s synthetic kerosene process for the production of sustainable aviation fuel Fats, oils and greases (FOG) co-processingASTM has approved 5% fats, oils and greases co-processing with petroleum intermediates as a potential SAF pathway. Used cooking oil and waste animal fats are among the popular sources for co-processing. The UK fuel specification DEF STAN 91-091 currently allows co-processing for up to 30%, an increase from the previous 5% limit.9 Deloitte analysis ASTM-approved, commercially available, actively used by major refiners.OMV produces SAF by co-processing used cooking oil (UCO) in the Schwechat refinery’s existing hydroprocessing units, supplying the resultant SAF via pipeline to Vienna Airport for Austrian Airlines. The companies delivered approximately 1,500 tonnes in 2022, marking the first Austrian production and use of SAF, with ongoing deliveries planned. Honeywell UOP offers co-processing technologies such as hydrotreating and hydrocracking to produce renewable diesel and partial SAF from diverse FOGs.OMV, 2021. OMV and Austrian Airlines are taking off with sustainable aviation fuel Honeywell UOP , 2024. Fuel a change for the better, co-processing technologies Turning Challenge into Opportunity: Supplier Voices from Heavy-Emitting Sectors 53