Biofuels in Aviation: A Credible Alternative to Achieve Carbon Neutrality
Sustainable aviation fuel (SAF) is a category of low-carbon fuel that can replace conventional jet fuel, either partially or (in theory) fully, in existing aircraft engines with minimal or no modification. It can reduce lifecycle carbon emissions by 50% to 80% compared to conventional jet fuel. SAF is currently the most mature pathway toward decarbonizing commercial aviation, but it faces significant challenges: production cost, feedstock availability, and the sheer scale of global aviation fuel demand. The transition is underway but far from complete.
Aviation is already the safest mode of transportation. SAF makes it cleaner too: The Airplane: The Safest Mode of Transportation!. For more on modern aircraft technical performance: What Is the Speed of a Commercial Airplane?.
What Is Sustainable Aviation Fuel?
SAF is produced from non-fossil-fuel feedstocks — biological materials, captured carbon dioxide, or even municipal solid waste. Unlike conventional jet fuel (Jet-A/Jet-A1), which is a petroleum product, SAF uses carbon that was recently in the atmosphere (via plant growth or waste decomposition) rather than carbon sequestered underground for millions of years.
The key environmental benefit is the lifecycle carbon calculation: although burning SAF releases CO₂ like conventional fuel, the feedstock absorbs CO₂ during its growth phase, creating a cycle rather than a net addition to atmospheric carbon. Well-to-wing lifecycle analyses show reductions of 50–80% compared to conventional jet fuel.
SAF Production Pathways
HEFA (Hydroprocessed Esters and Fatty Acids)
Currently the most commercially mature and widely used SAF pathway. HEFA processes waste fats, oils, and greases — used cooking oil, animal fat, algae oil — into a fuel that is chemically similar to conventional jet fuel. HEFA-SAF is already used in blends on commercial flights.
Power-to-Liquid (PtL) / e-fuels
E-fuels are produced by combining hydrogen (produced from renewable electricity) with CO₂ captured from the atmosphere or industrial sources. The resulting synthetic kerosene is completely identical to conventional jet fuel in composition. PtL has a higher theoretical carbon reduction potential than HEFA, but is currently far more expensive due to the energy intensity of the electrolysis and synthesis process.
Fischer-Tropsch synthesis
Biomass or municipal solid waste is gasified, and the resulting syngas is converted to liquid fuel via Fischer-Tropsch synthesis — a mature industrial process. This pathway can use a wide range of feedstocks and has high potential for scale, but is capital-intensive to build out.
Current State of SAF in Commercial Aviation
SAF is already certified for use in commercial aviation at up to 50% blend with conventional fuel (some pathways are certified up to 100% SAF, but infrastructure constraints mean blends are typically lower). Every major airline has SAF commitments, and some operate regular flights with SAF blends.
However, SAF currently represents less than 1% of global aviation fuel consumption. The gap between ambition and current scale is enormous. IATA's net zero by 2050 commitment requires SAF to supply approximately 65% of the required carbon reduction.
Challenges to Scaling SAF
Cost
SAF currently costs 2 to 5 times more than conventional jet fuel. This premium reflects the early stage of production infrastructure and the cost of feedstocks. As production scales and technology improves, costs are expected to fall — but the timeline is uncertain.
Feedstock availability
The HEFA pathway, while mature, depends on waste oils and fats that have limited global availability. Scaling SAF to meet even 30–40% of aviation fuel demand would require feedstocks beyond current waste oil supply — pushing toward agricultural residues, municipal waste, and eventually PtL at scale.
Infrastructure
Airports need SAF storage and delivery infrastructure. Most airports have limited SAF handling capacity, requiring investment in tanks, pipelines, and delivery systems. This investment is underway at major hubs but will take years to complete globally.
The Policy and Regulatory Framework
The European Union's ReFuelEU Aviation regulation mandates increasing SAF blending percentages: 2% by 2025, 6% by 2030, 70% by 2050. The US Inflation Reduction Act includes significant SAF tax credits. ICAO's CORSIA (Carbon Offsetting and Reduction Scheme for International Aviation) provides a market mechanism to fund emissions reductions including SAF.
Sources
IATA's Fly Net Zero initiative provides the industry's official roadmap for SAF and other decarbonization pathways: IATA: Fly Net Zero — Sustainable Aviation Fuels.
ICAO's Global Framework for Aviation Alternative Fuels (GFAAF) tracks SAF developments globally: International Civil Aviation Organization: SAF.
BBC's Future section has published an accessible, balanced overview of SAF's current state and challenges: BBC Science: Are sustainable aviation fuels the answer to flying's carbon problem?.
FAQ
Will SAF change anything for passengers?
No. SAF is designed as a drop-in fuel — chemically identical or equivalent to conventional jet fuel, usable in existing aircraft engines without modification. Passengers will notice nothing different about flights using SAF blends.
Is flying with SAF safer?
SAF meets the same fuel specification standards as conventional jet fuel (ASTM D7566). It is not safer or less safe — it is equivalent in terms of performance and safety, with lower carbon emissions. The safety of a flight depends on the aircraft, the crew, and the air traffic management system — not the specific certified fuel type.
What about hydrogen-powered aircraft?
Hydrogen is another long-term pathway being explored, with both direct combustion and fuel cell applications under development. However, it requires completely new aircraft designs and entirely different airport infrastructure. It is a post-2035 prospect at the earliest for commercial service.
A More Sustainable Flight Is Possible
Flying is already extraordinarily safe. It is becoming progressively cleaner. To understand the full picture: What Is the Cruising Altitude of a Commercial Airplane?.
And if the thought of boarding a plane still makes you anxious, our free quiz can help you identify the best path forward.