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Fossil fuels will account for more than three-quarters of fuel used by airlines beyond 2040 — according to the British government’s own projections — undermining Rachel Reeves’ claims that new technologies will turn aviation green.
The UK chancellor said on Thursday that “sustainable aviation fuels” are a “game-changer” in the debate over airport expansion, as she forecast that flights could take off from a new runway at Heathrow by 2035.
Reeves has angered environmentalists — but delighted some business groups — by encouraging Heathrow’s management to put forward plans for the third runway by this summer, with the hope of achieving planning permission before the next election in 2029.
“We’ve asked Heathrow to come forward with plans for that third runway by the summer, and we’ve said that it needs to meet strict rules about environmental and carbon emissions . . . I do believe they can. And Heathrow believes that they can as well,” Reeves told the BBC.
“I believe [sustainable aviation fuels] are a game-changer in the way that we fly and the carbon emissions,” she said.
But the government is only expecting 22 per cent of UK jet fuel to be supplied by SAF by 2040, according to a document dated December 2024.
SAF is made from a diverse range of sources, including crops, used cooking oil, household waste or hydrogen and can emit about 70 per cent less carbon dioxide over its life cycle than traditional aviation fuel.
It is also much more expensive than traditional jet fuel and is currently only available in small quantities.
The government in January introduced a mandate that required fuel producers to supply a portion of SAF for flights departing the UK.
The mandate is for 2 per cent of fuel to be SAF this year and steadily rises to reach 10 per cent by 2030 and 22 per cent by 2040.
The targets are in line with the aviation industry’s road map to reach net zero by 2050, which is heavily reliant on SAF but includes other measures such as more efficient conventional jets and air traffic control management.
But Tim Johnson, the director of the Aviation Environment Federation, said that under current forecasts the aviation industry would need all the available SAF in the UK in 2035 just to meet the growth in flight numbers from a third runway at Heathrow.
“This is not just this government having an over-optimistic take on SAF. It is consistent with every government in the world, because falling back on SAF allows them to continue to pursue growth,” he said.
Airlines are concerned that not enough SAF is being produced to hit the government’s targets and some have suggested that the SAF mandates might need to be watered down.
To help build a homegrown SAF industry, airlines and airports have urged ministers to speed up the rollout of a financial support mechanism to encourage investors to put money into production.
“There needs to be an alignment between the hugely welcome language around growth and boosting capacity at airports and incentivising the production of SAF,” said Tim Alderslade, chief executive of lobby group Airlines UK.
The government has outlined plans for an industry-funded “revenue certainty mechanism”, which would guarantee a minimum price for the fuel, similar to schemes used to underwrite nuclear and offshore wind projects.
But it is not expected to be introduced until the end of next year.
Noaman Al Adhami, head of UK at fuel company Alfanar, said he cannot close the financing for a plant to produce more than 130,000 tonnes of SAF a year on Teesside without the guarantees from the government on a revenue certainty mechanism.
“Without it will be very difficult, if not impossible, to close the project,” he said.
The previous Tory government’s plan to scale up SAF production called for five refineries to be under construction in the UK by the end of this year. None have been financed or built.
Global SAF production volumes reached 1.3bn litres last year and accounted for 0.3 per cent of global jet fuel production, according to Iata.
Given the challenges to scaling up SAF globally, Al Adhami said the UK was still ahead of many other countries, following its introduction of both the mandate and promise of a revenue support mechanism.
“At least now from a risk perspective and the capital we have invested in the UK, there is more certainty,” he said.
