The aviation industry burns through roughly 90 million tons of jet fuel annually. That number won’t drop significantly without a major shift in fuel technology. Sustainable Aviation Fuel, or SAF, has moved from theoretical solution to operational reality at most major airlines, yet production still lags behind demand by a factor of ten.
I’ve watched this transition unfold over the past three years. The shift isn’t coming from environmental idealism alone. Regulatory pressure is real. Airlines face increasingly strict carbon accounting requirements, investor scrutiny, and customer expectations. Yet despite all that momentum, SAF remains a niche product representing less than 0.1% of total jet fuel consumption globally.
What SAF Actually Is
Sustainable Aviation Fuel is technically not a single product. It’s a category of fuels that can replace conventional Jet A-1 while meeting strict aviation fuel specifications. The critical distinction: it’s drop-in compatible. Airlines don’t need to modify engines or fuel systems. Aircraft can run pure SAF, blends, or conventional fuel without any hardware changes.
SAF comes from biomass, waste feedstocks, or through synthetic production methods. The ASTM International standards (ASTM D7566) define what qualifies. Approved pathways today include:
HEFA (Hydroprocessed Esters and Fatty Acids): Takes used cooking oil and animal fats, removes impurities through hydroprocessing, and produces fuel chemically identical to conventional jet fuel. This is the dominant pathway currently. Neste pioneered this process and now operates the world’s largest SAF facility in Singapore, capable of producing 100,000 tons annually.
Fischer-Tropsch (FT): Converts synthesized gas (a mixture of hydrogen and carbon monoxide) into liquid hydrocarbons. This was originally developed during World War II. The pathway is flexible regarding feedstock. It can use biomass or coal as inputs. World Energy operates Fischer-Tropsch plants in the United States and produces roughly 50,000 tons of SAF annually through this method.
Alcohol-to-Jet (AtJ): Uses fermented alcohols as the base material, typically ethanol from biomass. Gevo is pursuing this pathway aggressively, though large-scale production remains years away. The process involves dehydrating alcohols and oligomerizing them into jet fuel range hydrocarbons.
Power-to-Liquid (PtL): Captures CO2 from the air or point sources, combines it with hydrogen from renewable electricity, and synthesizes fuel. This is the least mature pathway but theoretically the most scalable long-term since it doesn’t depend on limited biomass feedstocks.
Current Production vs. Reality
Here’s the gap that matters: global SAF production capacity reached approximately 100,000 tons in 2025. The International Air Transport Association projects aviation will need 3 billion tons of fuel annually by 2050. Even accounting for efficiency improvements and fleet electrification, SAF demand is projected to reach 500 million tons by 2050.
Current production represents roughly 0.1% of that future demand.
Major producers today are limited. Neste dominates with capacity spanning multiple facilities. World Energy produces through its Paramount Petroleum operation. SkyNRG operates in Europe and has partnerships with Shell and KLM. Gevo is ramping up but hasn’t yet hit commercial scale volumes. Several refineries have begun issuing tenders for SAF production rights, but converting existing facilities takes time and capital.
The bottleneck isn’t technology. It’s feedstock availability and production capacity. HEFA production depends on used cooking oil and animal fats, which are finite. You can’t scale beyond approximately 100 million tons annually without moving to dedicated energy crops, which introduces agricultural land-use complications. Fischer-Tropsch requires biomass or carbon feedstock. AtJ needs fermentation infrastructure. Power-to-Liquid needs cheap renewable electricity, which is still expensive for large-scale fuel production.
Airline Commitments and Reality
United Airlines committed to purchasing 200 million gallons of SAF through 2030. That sounds significant until you check the numbers. United burns approximately 1.5 billion gallons of fuel monthly. SAF commitments represent roughly 1% of their annual consumption.
Delta signed a long-term supply agreement with Gevo. Lufthansa committed to purchasing SAF to offset 10% of their fuel use by 2030. These commitments matter for market development. They signal demand. They provide offtake certainty that producers need to justify capital investments in new capacity.
Yet the pace of commitment outpaces production capacity. Airlines are signing deals for fuel that doesn’t exist yet. This is actually healthy market behavior. It drives investment in production facilities. But it also reveals the gap between ambition and infrastructure.
I’ve interviewed sustainability directors at three major carriers over the past eighteen months. The consistent message: they’re committed to SAF use, but they’re competing with chemical companies and other industries for limited feedstocks. Airlines will lose that competition on price if production doesn’t scale significantly.
The Price Problem
Jet A-1 traded in a range of $80-$120 per barrel through 2025. SAF trades at roughly 150-200% of that cost, depending on feedstock and production method.
This premium matters operationally. A carrier operating 300 aircraft burning 100,000 gallons daily faces a swing of $200,000-$400,000 in daily fuel costs by shifting to SAF. For a global network, that’s $70 million annually in added expense.
Some of that premium is temporary. HEFA production costs are dropping as facilities scale. Neste’s latest production announcements indicate cost reductions of 20-30% over the next two years. But the feedstock cost floor is real. Used cooking oil won’t become cheaper. FT production requires energy-intensive synthesis. PtL depends on renewable electricity costs, which are dropping but not falling fast enough to reach parity in the medium term.
Regulatory Drivers
The European Union’s ReFuelEU Aviation mandate requires SAF blending to reach 2% of jet fuel by 2025, escalating to 70% by 2050. This is the most aggressive regulatory framework globally. It’s already reshaping supply chains. Airlines operating into European airports must source SAF or face penalties.
The U.S. Inflation Reduction Act provided tax credits for SAF producers. A credit of $1.75 per gallon was initially available, dropping to $1.25 by 2026. These credits effectively subsidize production, making SAF more cost-competitive. Several new facilities in the United States are under development, partially justified by these incentives.
The challenge with regulatory mandates: if production capacity doesn’t exist, you’re mandating scarcity. European airlines were scrambling in late 2025 to secure SAF supplies ahead of blending requirements. Some paid premiums 300% above conventional fuel prices to meet compliance targets.
Looking Forward
I’m watching three developments closely. First, the opening of World Energy’s new facility in the Middle East, which could add 300,000 tons of capacity by 2027. Second, Gevo’s commercialization of AtJ production, which could provide an alternative feedstock pathway if they achieve the production volumes they’re targeting. Third, several carbon-capture-to-fuel projects that could establish PtL as commercially viable within five years.
The transition will happen. Physics and chemistry support it. The questions remaining are timing and cost. SAF will likely reach 5-10% blending across major carriers by 2030. Large-scale replacement of conventional fuel requires production that scales beyond anything we’ve seen in industrial history. That doesn’t happen overnight.
For now, SAF represents meaningful progress on a critical problem, limited by the same constraints that govern all energy transitions. Feedstock availability, capital requirements, and infrastructure development move slower than regulatory ambition.
Related reading: Check out the history of the Boeing 747 and early biofuel flight tests to see where this journey began with experimental sustainable fuel programs.