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To reduce aviation emissions, Sustainable Aviation Fuel (SAF) has a key immediate role to play, alongside other longer-term measures. SAF covers a range of lower-carbon alternatives to conventional aviation kerosene. Unlike hydrogen or battery powered aircraft, SAF can be used immediately in existing aircraft as a ‘drop in’ fuel, without needing to adapt fuel delivery infrastructure.
To support the shift to SAF, the UK Government has already created a SAF mandate. From January 2025, this requires fuel suppliers to use a minimum proportion of SAF in the UK aviation fuel mix, rising from 2% in 2025 to 10% in 2030 and 22% in 2040.
UK and global SAF production remains extremely limited, increasing the risk of missing mandate targets, according to the Climate Change Committee. Major oil companies remain largely absent from the sector, which is dominated by start-up projects often viewed as high-risk by private investors. To address these barriers, , the UK Government introduced the Sustainable Aviation Fuel Bill to parliament in May 2025.
The bill will create a ‘revenue certainty mechanism’ (RCM) to provide financial reassurance to investors in UK SAF plants, by creating a guaranteed price for SAF, known as the strike price. If the market price falls below this strike price, the SAF producer receives a top-up payment to cover the difference. Conversely, if the market price exceeds the strike price, the producer pays back the difference. The RCM is the first of its kind in the world and is a welcome innovation, especially as it will be funded by a levy on fuel suppliers under the ‘polluter pays’ principle, rather than by taxpayers.
However, not all SAF types are equally sustainable or scalable; government legislation should reflect this.
E-SAF—synthetic fuel made from air-captured carbon and renewable hydrogen—has the greatest decarbonisation potential, cutting lifecycle emissions by over 90% and avoiding land-use impacts and feedstock constraints of other SAFs. Only e-SAF can meet long-term aviation demand sustainably and at scale.
Roger Tyers, T&E UK’s Aviation Policy Manager advised, "The UK Government's Sustainable Aviation Fuel (SAF) bill is a welcome world-first. It will create a revenue certainty mechanism, which will be vital to create investor confidence and kick-start domestic SAF production.
The Government must now earmark part of the revenue support toward the production of synthetic e-SAF - the most scalable and sustainable form of SAF. This will be good for energy security, economic growth, exports and UK jobs in the production of a fuel of the future. Otherwise there is a real risk that RCM funding will flow only to less sustainable biofuel projects."
UK and EU airline mandates will soon drive demand for e-SAF. With global competition expected for limited supply, imports alone won’t suffice. The RCM offers a chance to secure UK-produced e-SAF, helping meet both domestic targets and international demand. Since the UK currently imports over 60% of its jet fuel, domestic e-SAF production could retain value and reduce dependency on foreign petrostates.
The ensure the RCM is effective, the government should implement the following measures:
Amend the SAF bill so that it explicitly commits a proportion of RCM support to e-SAF projects - at least enough to enable production to meet the SAF Mandate e-SAF quota of around 65,000 tonnes of e-SAF in 2030, equating to one large plant.
Consider e-SAF production as a key energy-intensive industry, as outlined in the recent industrial strategy, and eligible to benefit from lower electricity costs.
In June 2025, over 130 organisations—including T&E, NGOs, investors, and e-SAF producers—signed a joint appeal urging the government to use the RCM to back e-SAF production. This would secure the UK a ‘first mover’ advantage, boost energy security, and support jobs and exports. Without such support, the bill and RCM risk being a significant missed opportunity.
