HEFA Is Still the Clear Commercial Leader
Sustainable aviation fuel can be produced through several different technological pathways, but they are not all at the same stage of commercial development.
Today, Hydroprocessed Esters and Fatty Acids, or HEFA, remains the most technically and commercially mature route.
The process converts oils and fats — including used cooking oil, animal fats and vegetable oils — into hydrocarbon fuel using hydrogen and established refining technology.
EASA places HEFA at Technology Readiness Level 8–9, effectively at or close to full commercial maturity.
IATA describes HEFA as the only SAF pathway currently mature enough to support substantial near-term production growth.
Its advantage is proven technology. Its main limitation is feedstock availability.
As SAF production expands, HEFA producers increasingly compete for a finite pool of sustainable oils and fats already used by renewable diesel, biodiesel and other industries.
Alcohol-to-Jet and Fischer–Tropsch Are the Next Contenders
Alcohol-to-Jet is among the technologies closest behind HEFA.
The pathway converts ethanol or other alcohols into hydrocarbons that can be upgraded into aviation fuel.
EASA places Alcohol-to-Jet at approximately TRL 7–8, meaning the technology has progressed into demonstration and early commercial deployment but has not yet reached the maturity or scale of HEFA.
Alcohol-to-Jet has an important potential advantage: ethanol is already produced at large scale around the world, creating the possibility of building SAF production around existing agricultural and industrial supply chains.
Biomass gasification combined with Fischer–Tropsch synthesis is another advanced pathway.
It converts biomass, agricultural residues or waste into synthesis gas before transforming that gas into liquid hydrocarbons.
EASA places Gasification plus Fischer–Tropsch at roughly TRL 6–8.
Both technologies could broaden the range of feedstocks available to the SAF industry, but IATA says neither has yet achieved broad commercial maturity.
Power-to-Liquid Has the Largest Scaling Challenge
Power-to-Liquid offers a fundamentally different route.
Instead of relying primarily on biological feedstocks, PtL combines renewable hydrogen with captured carbon dioxide to produce synthetic hydrocarbons.
That means future production could theoretically expand without depending on the same limited waste oils and fats required by HEFA.
The challenge is maturity and cost.
EASA currently places Power-to-Liquid technologies broadly around TRL 5–8, depending on the configuration.
Large-scale plants require renewable electricity, electrolyzers, sustainable carbon supply and downstream synthesis technology to operate as one integrated industrial system.
Methanol-to-Jet is also emerging as a promising pathway and is currently progressing through aviation-fuel qualification work.
The commercial picture is therefore becoming increasingly clear.
HEFA is likely to remain dominant in the near term, but it cannot supply unlimited growth because sustainable lipid feedstocks are constrained.
Alcohol-to-Jet and Fischer–Tropsch are the leading candidates for the next wave of commercial expansion, while Power-to-Liquid could become strategically important as synthetic fuel mandates increase.
The industry’s challenge is not choosing a single winning technology.
Commercial-scale SAF will probably require several pathways developing simultaneously, each using different feedstocks, infrastructure and regional advantages.
Sources
European Union Aviation Safety Agency — What Are Sustainable Aviation Fuels?
International Air Transport Association — A Third of Announced SAF Capacity May Never Take Off, June 26, 2026
U.S. Department of Energy — Sustainable Aviation Fuel Pathways