High fryer or highflyer: How Used Cooking Oil is Powering the Aviation Industry

The aviation industry faces mounting pressure to decarbonize, yet viable alternatives to fossil jet fuel remain scarce. In response, airlines and fuel producers are turning to Sustainable Aviation Fuel (SAF), with used cooking oil (UCO) emerging as a promising feedstock. Repurposing fryer oil into jet fuel may seem unlikely, but UCO-based SAF is already cutting emissions. With aviation contributing 2-3% of global CO₂ emissions and demand for air travel rising, scaling up production is crucial. However, pricing, supply constraints, and investment risks pose significant challenges that could determine SAF’s future in the industry.

How Used Cooking Oil Becomes Jet Fuel

The transformation of used cooking oil into jet fuel happens through a process known as Hydro processed Esters and Fatty Acids (HEFA). This method, approved for commercial aviation, removes contaminants, hydrogenates the oil to eliminate oxygen, and refines it into hydrocarbons nearly identical to conventional jet fuel. The key advantage of HEFA-based SAF is that it requires no modifications to existing aircraft or fuelling infrastructure, making it the most viable short-term solution for sustainable aviation.

Market Regulation and Investment

Governments worldwide are pushing for SAF adoption through mandates, subsidies, and tax incentives. The European Union’s “Fit for 55” plan requires airlines to use at least 2% SAF by 2025, a figure that will rise to 63% by 2050. Meanwhile, in the U.S., the Inflation Reduction Act provides tax credits to SAF producers, driving domestic investment. Airlines are also making major commitments to SAF, with United Airlines securing a deal for 3.4 billion gallons of SAF by 2030, one of the largest agreements in the industry. Delta and American Airlines have partnered with fuel producers like Neste and World Energy, while aircraft manufacturers Airbus and Boeing have successfully conducted test flights powered entirely by SAF. Despite these investments, however, SAF still represents only 0.2% of global jet fuel consumption, highlighting the enormous challenge of scaling up production.

The Industry Standoff: Who Will Pay for SAF?

Despite enthusiasm for SAF, a standoff between airlines and oil companies over costs and supply threatens progress. Airlines argue that SAF, at two to five times the cost of conventional jet fuel, needs to be cheaper, but fuel producers hesitate to invest without guaranteed long-term demand. This deadlock raises doubts about meeting SAF mandates. Adding to concerns, Shell recently paused SAF investments, citing profitability risks, while Neste continues investing but warns that financial setbacks and policy uncertainty could slow expansion.

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Even if cost barriers are overcome, UCO supply remains a major challenge. With global production at 23 million metric tons annually, demand is soaring across biofuels, animal feed, and cosmetics, driving up costs. China, the largest UCO exporter, has restricted exports, impacting Europe and North America, which rely on imports for SAF production. In the U.S., farmers are protesting subsidies for imported UCO, arguing it undermines domestic biofuel crops. Adding to concerns, fraud in the UCO supply chain is rising, with reports of fresh vegetable oil being mislabelled as waste oil to exploit subsidies, underscoring the need for stricter oversight.

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Looking ahead

While UCO-based SAF offers emission reductions, it’s not a standalone solution for aviation’s carbon challenge. Supply constraints, pricing disputes, and policy uncertainties remain key hurdles. For SAF to scale up, airlines, refiners, and regulators must collaborate to expand production, cut costs, and diversify feedstocks. The industry stands at a crossroads, whether it accelerates, or stalls will shape the future of flight. One thing is clear: the push for sustainable skies is underway and used cooking oil is playing a bigger role than ever.