Sustainable aviation fuel (SAF) is a drop-in replacement for conventional fossil jet fuel, offering airlines a renewable, low-carbon alternative without engine or infrastructure changes. Derived from non-petroleum, renewable feedstocks like waste fats, oils, greases, municipal food and yard waste, or woody biomass, SAF slashes lifecycle greenhouse-gas emissions in aviation.
Expert behind this article
Jim Goodrich
Jim Goodrich is a pilot, aviation expert and founder of Tsunami Air.
What is SAF?
Sustainable aviation fuel (SAF) is a non-conventional (fossil-derived) aviation fuel made from non-petroleum feedstocks, which reduces emissions from air transportation. SAF is liquid fuel currently used in commercial aviation. Because SAF is chemically very similar to fossil jet fuel, it serves as a drop-in alternative that works in today's aircraft at blends of up to 50% without the need for engine modifications, and all quality tests are completed as per a traditional jet fuel. Approved under ASTM D7566, this green, environmentally friendly alternative performs at operationally equivalent levels to Jet A1 fuel. The Alcohol-to-Jet and Fischer-Tropsch SPK synthetic pathways are among the certified solutions turning non-petroleum-based renewable feedstocks, including woody biomass and the food-and-yard-waste portion of municipal solid waste, into new, low-carbon fuels. In the case of biofuels the CO2 released during combustion is absorbed from the atmosphere, making the fuel effectively carbon-neutral and helping the industry pursue ICAO's long-term aspirational goal of net-zero CO2 emissions by 2050.
Since SAF is obtained from sustainable resources, it reduces the amount of carbon released into the atmosphere. I see this as not just a technological advantage but also an economic and logistic one. I deem it as a prudent precautionary measure while the industry tries to come up with long-term pollution-free methods like electric propulsion.
Jim GoodrichPilot, Airplane Broker and Founder of Tsunami Air
What is SAF airplane fuel made from?
Sustainable aviation fuel (SAF) is an alternative fuel made from non-petroleum feedstocks. Today's production relies heavily on waste- and residue-based fats, oils and greases converted by hydroprocessed esters and fatty acids (HEFA) technology. The same pathway refines agricultural products like used cooking oil, animal fats and vegetable oils. Alcohol-to-Jet (AtJ) converts ethanol sourced from corn, sugarcane, related crops or waste. Second-generation bio-SAF is produced from non-food cellulosic materials including agricultural residues, woody biomass or municipal solid waste. Synthetic e-kerosene is made by combining green hydrogen with captured carbon dioxide in the power-to-liquid (PtL) pathway. PtL captures carbon dioxide and uses Fischer-Tropsch or similar gas-to-liquid processes to create synthesis gas that is transformed to match the structure of jet fuel.
SAF airplane fuel is made from combustible material obtained from consumed baking grease, agricultural leftovers, and municipal hard rubbish. Non-food plants like false flax or seaweed are as well-being grown. Power-to-liquid substances make artificial fuel from caught carbon CO2 and green hydrogen, reusing atmospheric carbon.
Is airplane fuel classified as SAF?
The International Air Transport Association defines sustainable aviation fuels as renewable or waste derived aviation fuels that meet sustainability criteria, reduce CO2 emissions by up to 80% compared to conventional jet fuel, and are made from feedstocks that do not compete with food crops or output, nor require incremental resource usage like water or land clearing. SAF feedstock must meet strict sustainability criteria and not cause land use changes. Non-petroleum based renewable feedstocks include fats/greases/oils, woody biomass, and the food and yard waste portion of municipal solid waste. Bio SAF alone cannot decarbonise aviation because renewable feedstocks, mostly used cooking oil, are a finite resource. Some barriers remain including competition for feedstock from other sectors and slow technology rollout. SAF technology faces scalability obstacles as waste biomass produces only a portion of total aviation fuel, and estimates of waste biofuel SAF capacity range from supplying 5.5% of European aviation fuel demand in 2030 to up to about 20% of U.S.'s aviation fuel demand in 2050. Achieving net zero will require both maximizing bio-based SAF production and scaling up power-to-liquid technologies. The industry is banking on fully synthetic e-fuels, molecules assembled from scratch out of hydrogen atoms and carbon dioxide.
I recognize SAF constitutes a substantial enhancement over traditional gasoline, yet I think the sustainability of Sustainable Aviation Fuel is a difficult matter. SAF reduces lifecycle oil releases, but dependence on raw material increases worries about the environmental footprint of the logistics cycle, possible rivalry with edible provisions, and soil consumption. Power-to-liquid applications make artificial petrol from green gas, utilize renewable energy, and make artificial fuels from carbon captured from the atmosphere.
Jim GoodrichPilot, Airplane Broker and Founder of Tsunami Air
