SolaReFuel: An Emerging EPFL Initiative Turning Sunlight, Recycled CO₂ and Water into Drop-in Fuels

Long-haul aviation, heavy road transport and large parts of industry share an awkward feature: they are very hard to run on electricity alone. They need energy-dense liquid hydrocarbons. That is exactly the gap that SolaReFuel, an emerging climate-tech initiative taking shape in the EPFL ecosystem, is trying to close – by turning sunlight, recycled CO₂ and water into “drop-in” fuels that work in today’s engines and fuel infrastructure without adding net emissions.

What SolaReFuel is trying to do

Publicly, SolaReFuel is still at an early stage, so detailed technical specifications are not yet available. What its founder, EPFL-trained researcher Mahendra Patel, describes is a solar-driven system that produces scalable, drop-in fuels for aviation, transport and industry – in his words, keeping the world moving “without adding to its emissions.” Patel’s research background is in photo-electrochemical devices that convert CO₂ and water into solar fuels, with a focus on material innovation, device engineering and performance optimisation. He has also been recognised among a cohort of young scientists working on climate technologies through the Inflection Award.

The core idea is simple to state and hard to engineer: use renewable energy with recycled CO₂ – sourced from the air or from unavoidable industrial streams – together with hydrogen split from water, and synthesise liquid hydrocarbons such as e-kerosene. Because the carbon in the fuel was taken out of the cycle in the first place, burning it does not add fresh fossil carbon to the atmosphere. This is the defossilisation logic at the heart of Power-to-X.

Built on a decade of EPFL solar-fuels research

SolaReFuel does not appear out of nowhere. EPFL has spent years building deep competence in converting sunlight into chemical energy. Researchers at the Laboratory of Renewable Energy Science and Engineering (LRESE), led by Sophia Haussener, have demonstrated a high-temperature solar electrolysis reactor that transforms concentrated sunlight and water into hydrogen, tested under real-sun conditions on a parabolic solar dish on the Lausanne campus. The roadmap there explicitly points towards co-electrolysis – co-producing hydrogen and carbon monoxide as synthesis gas, the feedstock for Fischer-Tropsch or methanol routes to liquid fuels.

In a complementary direction, an EPFL team around Kevin Sivula unveiled a solar-powered “artificial leaf” in 2023: a transparent, porous gas-diffusion electrode that harvests water vapour directly from humid air and produces hydrogen when exposed to sunlight. Laboratories such as the Laboratory of Photonics and Interfaces have long worked on the underlying semiconductor and water-splitting concepts. SolaReFuel can be read as an attempt to carry this laboratory lineage across the notorious gap between a research prototype and a real-world, commercially relevant system.

Where it fits in the Power-to-X landscape

Solar-driven fuels are no longer purely theoretical. A pilot system has already demonstrated the full thermochemical chain from CO₂ and water captured from ambient air to drop-in fuels such as methanol and kerosene. A 50-kW solar-tower reactor later showed the co-splitting of CO₂ and water into syngas at industrial-relevant scale, reaching a solar-to-syngas efficiency of around 4.1% – modest, but a meaningful technological milestone.

Switzerland already has a flagship in this space: SPIN member Synhelion, an ETH Zurich spin-off, inaugurated its DAWN demonstration plant for solar fuels in Jülich, Germany, in 2024, with SWISS lined up as a launch customer for the first commercial volumes of solar kerosene from 2027. The point is not that SolaReFuel competes head-on with such players, but that a Swiss innovation pipeline now stretches from EPFL benches all the way to demonstration plants and airline offtake agreements. A new EPFL-rooted venture entering this field strengthens that pipeline.

The hard part: cost and scale

The honest challenge for every solar- and electricity-based fuel is economics. Independent analyses put the cost of e-kerosene at roughly three times that of conventional jet fuel, and sometimes more. The single biggest cost driver is hydrogen, which can account for an estimated 66–83% of the total – and hydrogen cost is in turn dominated by the price of renewable electricity. Sourcing CO₂ adds further cost on top.

This is why approaches that try to integrate steps – coupling solar input, water splitting and CO₂ conversion as directly as possible – are interesting: every avoided conversion step and every point of efficiency gained chips away at that cost gap. Whether SolaReFuel’s specific architecture can deliver a decisive advantage is exactly the kind of question that only pilot data, not press releases, can answer. We will follow it on that basis.

Why it matters for the defossilisation agenda

Aviation alone is responsible for an estimated 2–3% of global CO₂ emissions, and that share is expected to grow as demand rises. For long-haul flight, batteries and hydrogen are unlikely to do the heavy lifting any time soon, which leaves drop-in synthetic fuels as one of the few credible options. Initiatives like SolaReFuel matter because they widen the set of technological bets being placed – and because they keep some of that bet-placing rooted in Swiss research.

At SPIN, the Swiss Power-to-X Collaborative Innovation Network, we see solar-to-liquid as a natural complement to electrolysis-based Power-to-X: same defossilisation goal, renewable energy with recycled CO₂ as the common thread, different physical routes to get there. SolaReFuel is one to watch as it moves – if it can – from the laboratory towards the runway.

Note: SolaReFuel is an early-stage initiative and several of its technical and commercial details are not yet public. Figures cited here (efficiencies, cost shares, emission shares) are drawn from peer-reviewed and industry sources on comparable solar-fuel and e-kerosene systems and are indicative (≈) rather than specific to SolaReFuel.