Decarbonising aviation at scale through synthesis of sustainable e-fuel: A techno-economic assessment

Abstract

Sustainable aviation fuels (SAFs) are crucial for decarbonising the aviation sector, particularly for long-haul flights which contribute the majority of emissions and have few feasible alternatives. This study explores the potential of carbon-neutral, synthetic electrofuels (e-fuels) as an economically competitive and scalable solution. A large-scale power-to-liquids plant is modelled producing H2 through electrolysis and capturing CO2 through low-temperature direct air capture (DAC), integrated with the Fischer-Tropsch process to synthesise ∼0.99 MMbbl/y of jet fuel, equivalent to approximately 1% of current UK demand. A variety of energy sources (nuclear and renewables), electrolyser technologies and electricity prices are incorporated to assess the current and future (by 2050) economic performance of the simulated plant. The study finds that a baseload power source appears important to remove the need for costly energy storage (currently 57% of liftime project costs for configurations using solely renewable energy) and reducing the levelised cost of fuel (LCOF). The highest potential for e-fuel is demonstrated when blending nuclear with renewables achieving a future LCOF of 296 $/bbl at a blended electricity price of 38.0 $/MWh using Proton Exchange Membrane electrolysis and 239 $/bbl using Solid Oxide electrolysis – competitive with alternative bio-based SAFs. Assuming future technology performance at an electricity price of 18.4–26.7 $/MWh, the LCOF reaches parity with the average fossil jet fuel price projected over the plant's operational life (186 $/bbl). A UK-based case study shows that on top of a current electricity generation capacity of ∼76.6 GW, delivering 334 TWh/y, an addition of at least 59.5 GW at a 90% capacity factor would be required to fulfil 63% of UK jet fuel demand by 2050. This illustrates low-carbon generation build rates to be a key limiting factor for widespread use of e-fuels, while bio-based SAFs have a significantly lower electrical consumption. Deployment of electrolysis and DAC capacity poses another significant constraint relative to currently small global capacities; however, these markets are emerging with fast growth expected, but likely limited by availability of low cost, low carbon electricity. To realise competitive e-fuel prices and significant production capacity, reduced energy prices and fast commercialisation and scaling of electrolysis/DAC technology manufacturing would be required.