Sustainable Aviation Fuel: What Airlines Need to Know About SAF

The Push for Cleaner Jet Fuel

Sustainable aviation fuel represents one of the most practical near-term solutions for reducing aviation’s carbon footprint. Unlike hydrogen or electric propulsion, which require entirely new aircraft designs, SAF works in existing engines with no modifications. Airlines can start using it today, and many already are.

The challenge is scale. SAF currently accounts for less than 1 percent of global jet fuel consumption, and ramping up production to meet industry decarbonization targets requires massive investment in new refineries and feedstock supply chains.

What Makes Fuel “Sustainable”

SAF can be produced from various feedstocks, including used cooking oil, agricultural waste, municipal solid waste, and purpose-grown energy crops. The key is lifecycle carbon reduction: while SAF still produces CO2 when burned, the carbon was recently captured from the atmosphere by plants rather than released from fossil reserves underground.

HEFA Pathway

Hydroprocessed esters and fatty acids (HEFA) fuel, made primarily from used cooking oil and animal fats, dominates current SAF production. This pathway is commercially mature and produces fuel nearly identical to petroleum jet fuel. However, feedstock availability limits how much HEFA fuel can be produced globally.

Fischer-Tropsch and Alcohol-to-Jet

Other production pathways are scaling up to address feedstock constraints. Fischer-Tropsch synthesis can convert agricultural residues, forestry waste, and municipal garbage into jet fuel. Alcohol-to-jet processes convert ethanol into aviation fuel. Power-to-liquid approaches use renewable electricity to produce synthetic fuels from captured CO2 and water.

Current Blending Limits

Aviation regulators currently approve SAF for use in blends up to 50 percent with conventional jet fuel. Most airlines use lower blend ratios due to limited SAF availability and higher costs. As production scales and costs decrease, blend ratios are expected to increase, with the industry working toward 100 percent SAF certification.

Airline Adoption

Major airlines are signing long-term SAF purchase agreements to secure supply and support production growth. United, Delta, American, and international carriers have committed billions of dollars to SAF procurement over the coming decade. Some airports, including Los Angeles and Amsterdam, now offer SAF through their regular fuel distribution systems.

Cost Premium

SAF currently costs two to four times more than conventional jet fuel, though prices are expected to decrease as production scales. Government incentives, including tax credits and blending mandates, are helping bridge the cost gap and attract investment in new production facilities.

Environmental Impact

Depending on feedstock and production pathway, SAF can reduce lifecycle carbon emissions by 50 to 80 percent compared to petroleum jet fuel. Some emerging pathways, particularly power-to-liquid using direct air capture, could potentially achieve carbon neutrality or even net-negative emissions.

SAF also produces fewer particulate emissions than conventional jet fuel, which may reduce contrail formation and the associated climate warming effects. Research into these non-CO2 climate impacts continues.

The Road Ahead

Meeting aviation industry commitments to achieve net-zero emissions by 2050 will require SAF to comprise a substantial majority of jet fuel consumption. This demands a roughly hundred-fold increase in production capacity over the next two decades. Achieving this scale requires continued policy support, technological advancement, and sustained investment across the aviation and energy sectors.