Sustainable aviation fuel has gotten complicated with all the industry jargon and competing claims flying around. As someone who has followed aviation technology for over a decade, I learned everything there is to know about SAF and where it actually stands today. Let me break it down for you.
In 2025, SAF reached 0.7% of global jet fuel consumption—double what we saw in 2024. That number sounds tiny, and honestly, it is. But within aviation circles, this modest milestone represents real progress in the long march toward decarbonization.
What SAF Actually Is
Sustainable aviation fuel is jet fuel made from sources other than petroleum. We’re talking used cooking oil, agricultural waste, municipal solid waste, and purpose-grown energy crops. The resulting fuel is chemically similar to conventional jet fuel and blends directly into existing fuel supplies.
To earn the “sustainable” label, a fuel needs lifecycle greenhouse gas reductions of at least 50% compared to regular jet fuel. Most approved SAF pathways hit 60-80% reductions, with some next-gen processes promising even better numbers.
Here’s what makes SAF attractive to airlines: it requires zero modifications to existing aircraft or airport infrastructure. It’s a drop-in replacement that works in current engines and fuel systems. That’s a massive advantage over hydrogen or electric propulsion, which would need entirely new aircraft designs.
The Different Ways to Make It
Probably should have led with this section, honestly. HEFA (Hydroprocessed Esters and Fatty Acids) takes waste oils and fats and converts them into jet fuel through hydroprocessing. This dominates current production because the technology is mature and proven.
Fischer-Tropsch synthesis uses heat and chemical reactions to convert carbon-containing feedstocks into liquid fuels. Originally developed for coal-to-liquids, modern FT processes use biomass or captured CO2 as feedstocks. Alcohol-to-Jet processes convert ethanol into jet fuel from various ethanol sources.
Power-to-Liquid represents the most promising long-term pathway. Using renewable electricity to produce hydrogen, then combining that hydrogen with captured CO2 to synthesize fuel, PtL can theoretically achieve near-zero lifecycle emissions. Costs remain steep right now, but the technology keeps advancing.
Putting 0.7% in Perspective
Global aviation burns through roughly 100 billion gallons of jet fuel every year. That 0.7% SAF share translates to about 700 million gallons—impressive growth from essentially zero a decade ago, but still a tiny fraction of what’s needed to meaningfully impact aviation emissions.
To hit net-zero by 2050, industry projections suggest SAF must represent 65% or more of total fuel consumption. Getting from 0.7% to 65% requires exponential growth sustained over 25 years. That’s a transformation without precedent in the fuel industry.
Why Production Can’t Keep Up
SAF production faces multiple constraints simultaneously. Feedstock availability limits current output—there simply isn’t enough used cooking oil and agricultural waste to produce fuel at the scale aviation needs.
Building production facilities requires massive capital investment. Each new SAF refinery costs $500 million to $2 billion, with construction timelines stretching 3-5 years. The industry needs dozens of these facilities just to meet 2030 targets.
Different pathways have different trade-offs. HEFA technology using waste oils is most mature but feedstock-limited. Fischer-Tropsch synthesis can use broader feedstocks but costs more. Power-to-liquid processes offer the best sustainability profile but remain the most expensive option available.
The Feedstock Scramble
That’s what makes the feedstock challenge particularly thorny for us in the aviation world—everyone wants the same stuff. Used cooking oil, the primary HEFA feedstock, faces demand from multiple sectors trying to decarbonize. Road transport biodiesel producers compete for the same UCO supply. Fraudulent labeling and supply chain integrity issues have popped up as UCO prices climbed.
Agricultural residues like corn stover and wheat straw could theoretically supply significant SAF production, but collection logistics prove challenging. These materials are scattered across vast agricultural areas, have seasonal availability, and compete with other uses including soil amendment and animal bedding.
The Cost Problem
SAF currently costs 3-5 times more than conventional jet fuel. This premium represents the single largest barrier to adoption. Airlines operate on razor-thin margins; absorbing fuel costs that triple overnight just isn’t viable.
Prices are falling as production scales, but the trajectory needs to steepen dramatically. Most projections show SAF reaching cost parity with conventional fuel only around 2040-2045, and that assumes aggressive scaling and policy support.
Until then, mandates, incentives, and voluntary commitments drive adoption. The EU’s ReFuelEU regulation requires 2% SAF in flights departing European airports by 2025, rising to 70% by 2050. Similar mandates are popping up globally.
What Airlines Are Doing
Major airlines have made ambitious SAF commitments, typically targeting 10% by 2030. United has invested directly in production facilities. Delta signed major offtake agreements. These forward contracts help secure financing for new production capacity.
Corporate travel programs increasingly specify SAF requirements. Microsoft, Google, and other tech giants have committed to purchasing SAF for employee travel. This book-and-claim system lets corporations fund SAF production even when the physical fuel gets used elsewhere.
The Scale-Up Challenge
Getting from 0.7% to meaningful impact means solving multiple problems at once: securing sustainable feedstocks at scale, financing dozens of production facilities, bringing down production costs, and creating policy frameworks that incentivize investment without distorting markets.
Each 1% of market share requires roughly 1 billion gallons annually. Reaching 10% by 2030 means building 10x current production capacity in five years. That’s an industrial mobilization without precedent.
Where Different Regions Stand
Europe leads in SAF adoption, driven by regulatory mandates and carbon pricing. The United States follows, with the Inflation Reduction Act providing significant production incentives. Asia-Pacific lags but is accelerating, with Singapore and Japan implementing support policies.
Supply concentrates in regions with production capacity. Airlines flying from SAF-abundant locations can meet mandates more easily; others may face shortages as requirements tighten.
What This Really Means Going Forward
Doubling SAF usage in a single year shows that production can scale rapidly when investment flows. The infrastructure, logistics, and certification systems work. What’s needed is acceleration of a proven pathway, not technological breakthroughs.
But the math remains daunting. At current doubling rates, SAF would reach meaningful scale only after 2040. Hitting industry decarbonization targets requires even faster growth—a challenge that depends as much on policy and investment as on technology.
The 0.7% milestone marks genuine progress in aviation’s sustainability journey. It proves SAF works, production can scale, and airlines will buy it when available. What comes next determines whether aviation meets its climate commitments. The slow climb of SAF must become a rapid ascent—and the runway for that acceleration is shorter than most people realize.
