Planes powered by air might sound far-fetched, but advances in sustainable aviation fuel (SAF) suggest it could become reality in the near future. This third generation of SAF, known as e-fuel or “power-to-liquid” fuel, offers a net-zero alternative to traditional jet fuel. Though the science behind it is relatively simple, the real challenge lies in affordability, with production costs remaining significantly higher than both bio-based SAF and standard kerosene-based jet fuel.
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E-fuel is produced by converting carbon dioxide—sourced from either the atmosphere or industrial emissions—into carbon monoxide, using electrolysis or hydrogen. These compounds are then transformed into hydrocarbon fuel. Experts like Conor Madigan, CEO of Aether Fuels, highlight that while the environmental benefits are clear, the financial barrier remains steep. At present, e-fuel costs around $8,720 per tonne, compared to $2,365 for bio-based SAF and just $830 for conventional jet fuel.
Duncan McCourt, head of the industry group Sustainable Aviation, emphasises that cost-effective scaling is key. Unlike biofuels, e-fuels are not limited by feedstock supply or land use, but require vast amounts of renewable energy and rare green hydrogen to become viable. McCourt argues that while the UK and EU currently lead in supportive policy, much more must be done to encourage investment and innovation. Capturing carbon from the air is especially energy-intensive, further contributing to the high cost of production.
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Despite these challenges, the aviation sector is showing interest. Virgin Atlantic flew a Boeing 787 Dreamliner using cooking oil from Heathrow to New York in 2023, and other major airlines like United, Emirates and British Airways have all tested SAF. Still, experts agree that widespread adoption of e-fuel will depend heavily on government backing, investment in renewable energy, and a global push to drive down production costs.
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