Supply constraints and rising costs threaten the UK’s ability to meet sustainable aviation fuel (SAF) targets, warns UK governmental advisory body Climate Change Committee (CCC) in its Seventh Carbon Budget.
SAF is now projected to account for just 6% of the UK’s aviation fuel mix by 2030, falling short of the government’s 10% goal. By 2040, this figure is expected to reach 17%, yet the CCC warns that feedstock limitations and intensifying global competition could hinder progress.
The report, which came out in late February but is still being picked over, highlights that access to sustainable feedstocks, such as used cooking oils and agricultural waste, remains a key challenge. The UK faces stiff competition from the US, EU, and China, which have implemented more aggressive SAF policies and incentives. Without sufficient domestic production, the UK could become a net importer of SAF, making it more expensive and less competitive.
Even if supply challenges are addressed, costs remain a major obstacle. The CCC report states, “Synthetic fuels will remain around seven times more expensive than conventional kerosene by 2050, while biomass-derived SAF is projected to be twice as expensive.” These high costs make SAF commercially unviable without policy support or technological advances. Direct air capture and storage could be a cheaper alternative to fuel switching, it is reckoned.
Murray Douglas, Head of Hydrogen Research at global energy consultancy Wood Mackenzie, recently framed similar concerns about the cost challenges facing SAF and other synthetic fuels. He told gasworld, “Hydrogen needs to be below $1.50 per kg for e-fuels to work, and we’re nowhere near that. Even in places with ultra-cheap renewables, we’re looking at costs that just don’t make sense.” The economics are particularly difficult for aviation fuels, which require competitive pricing to remain commercially viable, since profit margins for airlines are always thin.
Douglas further noted that e-SAF, once considered a near-term solution, is unlikely to be viable at scale before the 2040s.
If the UK fails to scale up SAF production, the CCC warns that aviation may have to implement demand management measures, such as higher ticket prices or restrictions on flight growth. The report states, “SAF remains a key part of the decarbonisation strategy, but its scalability is uncertain.”
The UK’s SAF mandate, which came into force on 1 January 2025, requires at least 2% of all jet fuel to be SAF this year, increasing to 10% by 2030 and 22% by 2040. This timeline is expected to deliver 1.2 million tonnes of SAF annually by 2030, reducing carbon emissions by 6.3 megatonnes per year a decade later.
But achieving these targets is now uncertain due to capacity, technology, scaling, and investment challenges.
Four UK airports – Heathrow, Gatwick, Manchester, and Stansted – currently have SAF handling capabilities.
