An aviation biofuel (also known as bio-jet fuel, Note: Investable Universe>About bio-aviation fuel (BAF), semi-synthetic jet fuelASTM International. (2026). ASTM D7566-26a Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons. West Conshohocken, PA. ASTM Store.Ministry of Defence. (2024). Turbine Fuel, Kerosene Type, Jet A1; NATO Code: F-35; Joint Service Designation: AVTUR (Defence Standard 91-091 Issue 18). jig.org, or sustainable aviation fuel (SAF)) is a biofuel used to power aircraft. The International Air Transport Association (IATA) considers it a key element in reducing the environmental impact of aviation. Aviation biofuel can be used to decarbonize otherwise hard-to-decarbonise medium and long-haul air travel via "drop-in-replacement" which does not require extensive modification to aircraft engine design. Synthetic paraffinic kerosene (SPK) refers to any non-petroleum-based hydrocarbon mixture designed as a blending component or complete replacement of kerosene jet fuel.
Not all bio-fuels are produced in a sustainable manner. Typically sustainable aviation fuel is certified as being sustainable by a third-party organisation and may benefit from emissions trading or carbon-credit schemes depending on local laws.
Biofuels are biomass-derived fuels from plants, animals, or waste; depending on which type of biomass is used, they could lower emissions by 20–98% compared to conventional jet fuel. The first test flight using blended biofuel was in 2008, and in 2011, blended fuels with 50% biofuels were allowed on commercial flights. In 2023 SAF production was 600 million liters, representing 0.2% of global jet fuel use. By 2024, SAF production was to increase to 1.3 billion liters (1 million tonnes), representing 0.3% of global jet fuel consumption and 11% of global renewable fuel production. This increase came as major US production facilities delayed their ramp-up until 2025, having initially been expected to reach 1.9 billion liters.
Aviation biofuel can be produced from upgraded plant or animal sources such as Jatropha, algae, tallows, waste oils, palm oil, Babassu, and Camelina (bio-SPK); from solid biomass using pyrolysis processed with a Fischer–Tropsch process (FT-SPK); with an alcohol-to-jet (ATJ) process from waste fermentation; or from synthetic biology through a solar reactor. Pathways which use electricity-derived hydrogen as a feedstock are called Electrofuels or e-fuels. Small piston engines can be modified to burn ethanol as a replacement for aviation gasoline.
SAF technology faces significant challenges due to feedstock constraints. The oils and fats used in production of hydrotreated esters and fatty acids (HEFA), crucial for SAF production, are in limited supply as demand increases. Although advanced e-fuels technology, which combines waste with clean hydrogen, presents a promising solution, it is still under development and comes with high costs. To overcome these issues, SAF developers are exploring more readily available feedstocks such as woody biomass and agricultural and municipal waste, aiming to produce lower-carbon jet fuel more sustainably and efficiently.
History
Technical development The use of vegetable oils as a feedstock for aviation fuel has been studied for decades. Dunn (2001) highlighted the potential of vegetable oils as alternative jet fuel sources, which fundamentally underpins the modern HEFA pathway.
By 2015, cultivation of fatty acid methyl esters and alkenones from the algae, Isochrysis, was under research.
By 2023, 90% of biofuel was made from oilseed and sugarcane which are grown for this purpose only.
Some perspectives suggest that to overcome these economic challenges, SAF production should be integrated into biorefineries that also foster the production of renewable chemicals, thereby diversifying revenue streams.
Flights using biofuels
The first flight using blended biofuel took place in 2008. Virgin Atlantic used it to fly a commercial airliner, using feedstocks such as algae. The Sustainable Aviation Fuel Users Group was formed in September 2008. It gathers 25 airlines. All members have signed a Sustainability Pledge and are members of the Roundtable of Sustainable Biofuels (RSB) or ISEAL Alliance. That year, Boeing was co-chair of the Algal Biomass Organization, joined by air carriers and biofuel technology developer UOP LLC (Honeywell). In 2023 Virgin Atlantic completed "Flight 100", a 3543 mile flight from London Heathrow to New York JFK using a Boeing 787, which was the world’s first transatlantic flight flown on 100% Sustainable Aviation Fuel (SAF) by a commercial airline.
Development of Standard Specifications
By June 2011, the revised Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons (ASTM D7566) allowed commercial airlines to blend up to 50% biofuels with conventional jet fuel. The safety and performance of jet fuel used in passenger flights is certified by ASTM International. Biofuels were approved for commercial use after a multi-year technical review from aircraft makers, engine manufacturers and oil companies. Thereafter some airlines experimented with biofuels on commercial flights. As of July 2020, seven annexes to D7566 were published, including various biofuel types: Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK, 2009) Hydroprocessed Esters and Fatty Acids Synthetic Paraffinic Kerosene (HEFA-SPK, 2011) usHydroprocessed Fermented Sugars to Synthetic Isoparaffins (HFS-SIP, 2014) Fischer-Tropsch Synthetic Paraffinic Kerosene with Aromatics (FT-SPK/A, 2015) Alcohol to Jet Synthetic Paraffinic Kerosene (ATJ-SPK, 2016) Catalytic Hydrothermolysis Synthesized Kerosene (CH-SK, or CHJ; 2020).
SAF Targets
In 2009, the IATA committed to achieving carbon-neutral growth by 2020, and to halve carbon emissions by 2050.
In 2010, Boeing announced a target 1% of global aviation fuels by 2015.
In fall 2016, the International Civil Aviation Organization announced plans for multiple measures including the development and deployment of sustainable aviation fuels.
Biofuel provider Solena filed for bankruptcy in 2015.
In 2019, 0.1% of fuel was SAF: The International Air Transport Association (IATA) supported the adoption of Sustainable Aviation fuel, aiming in 2019 for 2% share by 2025: .
By 2016, Thomas Brueck of Munich TU was forecasting that algaculture could provide 3–5% of jet fuel needs by 2050.
In early 2021, Boeing's CEO Dave Calhoun said drop-in sustainable aviation fuels are "the only answer between now and 2050" to reduce carbon emissions. In May 2021, the International Air Transport Association (IATA) set a goal for the aviation industry to achieve net-zero carbon emissions by 2050 with SAF as the key component.
DHL achieved a 10% SAF blending ratio within their air cargo operations in 2025 and aims to increase the share of SAF to 30% by 2030.
The European Commission's ReFuel EU Aviation initiative sets requirements for aviation fuel suppliers to gradually increase the share of SAF blended into the conventional aviation fuel supplied at EU airports. It requires 6% of all aviation fuel supplied at EU airports to come from sustainable aviation fuels by 2030, rising to 20% by 2035, and reaching 70% by 2050. A percentage of fuels is required to be e-fuels, rising from 1.2% in 2030 to 35% in 2050.
The UK government's SAF Mandate requires 10% of aviation fuel to come from sustainable sources by 2030 and rising to 20% by 2040. A sub-percentage of fuel is required to come from power-to-liquid technologies (essentially the same as the EU e-fuels sub-target), rising from 0.2% in 2028 to 3.5% in 2040.
Grants and Investments In December 2011, the FAA awarded US$7.7 million to eight companies to develop drop-in sustainable fuels, especially from alcohols, sugars, biomass, and organic matter such as pyrolysis oils, within its and programs.
Dozens of companies received hundreds of millions in venture capital from 2005 to 2012 to extract fuel oil from algae, some promising competitively-priced fuel by 2012 and production of by 2012-2014. By 2017 most companies had disappeared or changed their business plans to focus on other markets.
The 2022 Inflation Reduction Act introduced the Fueling Aviation's Sustainable Transition (FAST) Grant Program. The program provides $244.5 million in grants for SAF-related "production, transportation, blending, and storage." In November, 2022, sustainable aviation fuels were a topic at COP26.
Production Jet fuel is a mixture of various hydrocarbons. The mixture is restricted by product requirements, for example, freezing point and smoke point. Jet fuels are sometimes classified as kerosene or naphtha-type. Kerosene-type fuels include Jet A, Jet A-1, JP-5 and JP-8. Naphtha-type jet fuels, sometimes referred to as "wide-cut" jet fuel, include Jet B and JP-4.
"Drop-in" biofuels are biofuels that are interchangeable with conventional fuels. Deriving "drop-in" jet fuel from bio-based sources is ASTM approved via two routes: blending and co-processing. ASTM has found it safe to blend in 50% SPK into regular jet fuels. Tests have been done with blending synthetic paraffinic kerosene (SPK) in considerably higher concentrations.
HEFA-SPK Hydroprocessed Esters and Fatty Acids Synthetic Paraffinic Kerosine (HEFA-SPK) is a specific type of hydrotreated vegetable oil fuel. this was the only mature technology (but by 2024 FT-SPK was commercialized as well). HEFA-SPK was approved by Altair Engineering for use in 2011. HEFA-SPK is produced by the deoxygenation and hydroprocessing of the feedstock fatty acids of vegetable oils such as jatropha, and camelina, algae, or animal fats such as tallow. The Diamond Green Diesel facility in Port Arthur, Texas, operated by Valero Energy, began producing SAF in late 2024, using the HEFA-SPK process. FT-SPK Processing solid biomass using pyrolysis can produce oil or gasification to produce a syngas that is processed into FT SPK (Fischer–Tropsch Synthetic Paraffinic Kerosene). ATJ-SPK The alcohol-to-jet (ATJ) pathway takes alcohols such as ethanol or butanol and de-oxygenates and processes them into jet fuels. Companies such as LanzaTech have created ATJ-SPK from in flue gases. The ethanol is produced from CO in the flue gases using microbes such as Clostridium autoethanogenum. In 2016 LanzaTech demonstrated its technology at Pilot scale in NZ – using Industrial waste gases from the steel industry as a feedstock.Voegele, E. November 2009. "Waste to ethanol projects move forward", Ethanol Producer Magazine Gevo developed technology to retrofit existing ethanol plants to produce isobutanol. Alcohol-to-Jet Synthetic Paraffinic Kerosene (ATJ-SPK) is a proven pathway to deliver bio-based, low-carbon fuel.
Certified processes