The UK is to mandate a 10% mix of sustainable aviation fuels (SAF) in aircraft fuels from 2030 and sees hydrogen as a key decarbonisation fuel for the sector, but the government’s new net-zero aviation strategy has little to say about how it plans to clear a pathway for H2.
The UK’s “Jet Zero” strategy, released on Tuesday, places a heavy emphasis on “guilt-free flying” for passengers, with SAF, in particular, touted as a route to decarbonisation, rather than flight reduction.
It defines SAF — a term often used interchangeably with biofuel — as “renewable or waste-derived aviation fuels that meet specific sustainability criteria and can be used in existing aircraft without significant engine modifications”.
The strategy lauds liquid H2 as an important zero emission aviation fuel and highlighted some of the activity surrounding hydrogen-powered flight, such as Airbus’ efforts, but set no new targets, made no new forecasts and importantly, committed no new funds.
The lack of substance behind the rhetoric suggests the UK may be quietly hedging its bets on pure hydrogen fuel in aviation on account of the many technical challenges — but without ruling it out.
On SAF, however, the Jet Zero strategy set the ball rolling. As well as putting an obligation on fuel suppliers to mix at least 10% SAF into aviation fuel mix by 2030, it also committed £1m ($1.2m) to support the delivery of the first net-zero transatlantic flight running on 100% SAF.
The obligation approach mirrors that taken by the UK government on road transport fuel, which now comprises 10% biofuels.
And a new £165m Advanced Fuels Fund will help meet a new pledge: to have five commercial-scale SAF plants under construction in the UK by 2025.
“Complete fantasy”
The strategy’s “guilt-free flying” mantra incensed environmental campaigners, who lambasted it as greenwash.
“On UK’s hottest day ever, government’s outrageous greenwash pours jet fuel on the flames,” tweeted Caroline Lucas, the UK’s only Green Party MP. “A ‘net zero aviation industry’ — while airport expansions and huge increase in passengers continue apace — isn’t a strategy, it’s pie-in-the-sky thinking.”
Climate campaign group Possible said: “All of the technology solutions in this aviation strategy are a complete fantasy.”
The group, which is highly critical of the land use issues surrounding biofuels, added: “‘Sustainable aviation fuels’? Extremely detrimental to the climate.
“The truth is there is only one method for reducing aviation emissions which we know works: reducing the number of flights.”
Round-trip efficiency
Some studies into the decarbonisation of aviation — which accounts for 2% of global emissions today — have suggested that hydrogen could play a role in short-haul flights which are out of range of battery-powered planes.
An Energy Transitions Commission report, released this week, suggests that battery-powered planes could fly as far as 1,000km by 2050, while hydrogen fuelled planes can travel around 2,500km.
However, the round-trip efficiency of a green-hydrogen-fuelled combustion jet engine is just 33%, according to analysis from the Hydrogen Science Coalition, meaning that 100kWh of renewable energy will result in just 33kWh of energy delivered by the turbofan.
By contrast to the details-light approach to hydrogen in aviation, the UK has set ambitious targets for hydrogen production, earlier this year doubling its hydrogen production ambition to 10GW by 2030, half of which should be derived from near-zero-carbon electricity, rather than fossil gas.
And today it launched the world’s first clean hydrogen production subsidy scheme, which aims to use a contracts-for-difference (CfD) style scheme to incentivise development of green hydrogen, as well as blue (made from fossil gas) and pink (made from nuclear power).
