Sustainable aviation fuel
Sustainable aviation fuel (SAF) is a non-fossil aviation fuel made from renewable or waste-based carbon sources that is certified for blending with conventional jet fuel for commercial flight.
SAF is designed to reduce lifecycle emissions compared with fossil jet fuel while remaining fully compatible with existing aircraft, airport infrastructure, and fueling systems.
Quick answers on this page
What is sustainable aviation fuel?
Sustainable aviation fuel is aviation fuel produced from non-petroleum feedstocks that meet approved aviation fuel standards when blended with conventional jet fuel.
The final fuel is chemically similar to Jet-A and functions as a drop-in fuel for commercial aviation.
Common SAF feedstocks include:
- used cooking oil
- animal fats
- forestry residues
- agricultural residues
- municipal solid waste
- biogas
- renewable hydrogen and captured carbon dioxide
For a full definition, see What is sustainable aviation fuel.
Why is sustainable aviation fuel important?
SAF is one of the most practical near-term options for reducing emissions from aviation because aircraft require high-energy liquid fuels.
Long-haul aviation cannot currently rely on battery systems at commercial scale, so liquid hydrocarbon fuels remain essential.
SAF allows emissions reduction without changing:
- aircraft engines
- airport fueling systems
- fuel logistics infrastructure
How is sustainable aviation fuel produced?
SAF is produced through several approved conversion pathways that transform renewable feedstocks into aviation-range hydrocarbons.
Major pathways include:
- Hydroprocessed Esters and Fatty Acids (HEFA)
- Fischer-Tropsch synthesis
- Alcohol-to-jet
- Power-to-liquids
Each pathway uses different feedstocks and chemical steps to produce fuel suitable for aviation blending.
For process detail, see Sustainable aviation fuel production.
What feedstocks are used to make SAF?
Different SAF pathways depend on different feedstocks, and feedstock availability strongly affects project design.
Examples include:
Lipid-based feedstocks
Waste and residue from used cooking oil, tallow, vegetable oils
Solid biomass feedstocks
Forestry residues, agricultural residues
Biogas feedstocks
Agricultural and other waste processed through anaerobic digesters
Solid waste-derived feedstocks
Municipal and other solid waste
Synthetic feedstocks
Renewable hydrogen with captured carbon dioxide
Feedstock choice influences carbon intensity, scale, and economics.
How does Fischer-Tropsch technology support SAF production?
Fischer-Tropsch is one approved SAF pathway that converts synthesis gas into synthetic hydrocarbons later upgraded into aviation fuel fractions.
The pathway includes:
- Feedstock conversion into synthesis gas
- Fischer-Tropsch synthesis
- Hydrocarbon upgrading into jet-range fuel molecules
This pathway produces Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK).
See:
Are all SAF pathways approved for commercial aviation?
No. SAF must meet strict technical standards before it can be used in aircraft.
Approved fuels are governed under ASTM International D7566.
Approval defines:
- molecular requirements
- blending limits
- fuel property standards
For pathway details, see ASTM approved SAF pathways.
Can sustainable aviation fuel fully replace conventional jet fuel?
Today SAF is blended with conventional jet fuel under approved blending limits.
Blending ensures compatibility with aircraft fuel systems and certification requirements.
Ongoing progress continues toward higher blend levels and fully synthetic aviation fuels.
Why is SAF expanding globally?
SAF growth is being driven by airline demand, fuel policy, decarbonization targets, and energy security across multiple regions.
Growth drivers include:
- airline net-zero commitments
- fuel mandates
- low-carbon fuel incentives
- emerging project investment
- focus on domestic energy production
Regional policy increasingly influences where SAF projects move first.
Where does Velocys fit in sustainable aviation fuel production?
Velocys supports SAF production through Fischer-Tropsch technology licensing for projects using syngas-based pathways.
Its technology is used where projects require:
- feedstock flexibility
- modular or stick-built FT systems
- synthetic hydrocarbon production for aviation fuel upgrading
Velocys supports project developers and engineering partners building SAF systems based on Fischer-Tropsch synthesis.
Frequently asked questions
Is sustainable aviation fuel chemically different from jet fuel?
SAF is hydrocarbon-based and designed to meet aviation fuel requirements when blended appropriately.
Can SAF be made from waste?
Yes. Several approved SAF pathways use waste-derived carbon sources.
Does SAF require new aircraft?
No. Approved SAF works within existing aircraft fleets.
Is Fischer-Tropsch the only SAF pathway?
No. Multiple approved pathways exist, including HEFA and alcohol-to-jet.