Solar power has become a mainstream contributor to the global energy mix, emerging as the largest driver of energy supply growth in 2025.
Yet natural gas remained close behind that year, a reminder that full electrification is still far off and that many sectors remain tied to fossil fuels.
Renewable fuels are increasingly seen as a bridge for these hard-to-abate industries, and solar power is now central to several methods for producing them, including sustainable aviation fuel (SAF), ethanol, and hydrogen.
Attaurrahman Ojindaram Saibasan, senior analyst at GlobalData, says interest in solar-derived fuels is accelerating because they sidestep the constraints of biomass, such as land scarcity, water demand, and competition with agriculture, by drawing on sunlight and captured carbon dioxide instead.
The scale of the challenge is significant.
The International Civil Aviation Organisation projects a SAF supply gap of around 24 million tonnes by 2035.
Global hydrogen demand reached 100 million tonnes in 2024, almost entirely supplied through fossil fuels, according to the International Energy Agency.
Bioethanol production, meanwhile, still relies heavily on corn and sugarcane, raising concerns about food security in major producing markets like the United States.
Researchers at the University of Sheffield and the East China University of Science and Technology have designed a solar-powered calciner that could make SAF production cheaper and less carbon-intensive.
Their system replaces the fossil-fuel combustion typically used in direct air capture with concentrated solar heat, channelling energy through a heliostat field and parabolic mirrors.
Meihong Wang, professor of energy systems at Sheffield and the study’s lead researcher, describes the process: “Solar energy is reflected by the heliostat field and parabolic mirror, then focused onto the front wall of the solar calciner.”
The captured carbon dioxide is then combined with hydrogen and fed into a catalytic converter to produce fuel.
Modelling published in Nature Communications suggests the approach could bring SAF production costs down to US$4.62 per kilogram, compared with US$5.60 for conventional carbon capture routes, though still well above the roughly $0.75 per kilogram cost of standard jet fuel in 2025.
A separate effort at the University of Cambridge has produced an “artificial leaf” capable of converting carbon dioxide and water directly into ethanol and propanol using sunlight.
The device pairs light-absorbing layers of bismuth vanadate and perovskite with a copper-palladium catalyst that encourages longer carbon chains to form, favouring multi-carbon alcohols over the carbon monoxide typically produced by such reactions.
First demonstrated at a 2022 European Innovation Council competition and published in Nature Energy in 2023, the technology remains a proof of concept, though its developers say ongoing refinements have improved its efficiency and that the modular design should support future scale-up.
A third approach, from the Photreon start-up at the Karlsruhe Institute of Technology, skips electricity generation altogether.
Its photoreactor panels use sunlight to trigger photocatalysis, splitting water into hydrogen and oxygen without electrolysers, wiring, or a grid connection.
The team argues this simpler design could sharply cut the cost of green hydrogen, currently priced between US$10 and US$16 per kilogram in many projects, well above the roughly US$3 per kilogram needed for commercial viability.
Developers Anselm Dreher and Maren Cordts say the approach could also reduce reliance on scarce materials: “Photreon offers a technology that lessens the dependency on rare materials and can be manufactured locally.”
With a one-square-metre prototype already tested, the team envisions applications ranging from on-site hydrogen supply for factories to large-scale solar hydrogen farms built for export.
Across all three technologies, researchers caution that further development, investment, and supportive policy will be needed before solar-derived fuels can compete on price with fossil-fuel alternatives.
