Andrew Symes holds up a vial containing a thick, cloudy liquid. It may not look like the aviation fuel of the future, but OXCCU’s co-founder and chief executive believes the fluid could help power the sector to its zero-carbon goals. His Oxford University chemistry department spin-out has patented a simplified method of producing long-chain hydrocarbons from carbon dioxide and hydrogen – and the tube contains early results.
Some believe hydrogen-derived fuels are the key to unlocking greener flight as they can replace or supplement Jet A in aircraft engines and are more environmentally sound than manufacturing sustainable aviation fuel (SAF) from feedstock, recycled plastics, or biowaste. If they can be produced at scale, the theory is they could supplant batteries or hydrogen fuel cells as a solution to the industry’s zero carbon conundrum.
The problem is these so-called e-fuels have traditionally been complicated and expensive to make. OXCCU (pronounced Ox-CCU) maintains it has simplified the process from a multi-step and energy intensive exercise to just a single stage that avoids firstly converting CO2 to carbon monoxide. Instead, using its own catalyst and reactor – products of a decade of university research – it turns CO2 and hydrogen directly to SAF.
OXCCU currently produces “Ox.efuel” at very low volumes – 1.2 litres (0.3USgal) a day – from its “OX1” demonstration plant at Oxford airport that began fully operating in August. The two-storey, Portakabin-sized lab is intended to prove the concept before OXCCU opens a larger facility at Hull’s Saltend Chemical Park in 2026.
“OX2” will be able to create 200 litres of SAF per day. Though still too small for a commercial operation, it will “generate the data and litres of fuel we need” to carry out tests on an aircraft auxiliary power unit and convince energy firms to come on board, says Symes.
OXCCU will retain intellectual property rights on the catalyst and reactor design. “Our model is to license,” he says. “We hope to be licensing globally by 2028.”
Those behind OXCCU have an impressive academic record. Symes has a first-class degree in chemistry from Oxford and a background in climate-tech start-ups. He joined OXCCU as chief executive in 2022.
His fellow founders have a longer connection with the business. Dr Jane Lin was the climate-tech lead at the university and helped spin out OXCCU. Dr Tiancun Xiao is a world-renowned catalysts expert.
While the science can be tricky to grasp for those without an advanced chemistry background, Symes insists the pathway to the reaction is straightforward. The secret to its ‘achemy’ is its proprietorial iron catalyst. “All other e-fuel companies are focused on a two-step approach. To our knowledge, we are the only SAF company with a one-step catalyst,” he says.
The process itself was outlined in an academic paper published four years ago in the journal Nature Communications: the patented iron catalyst converts CO2 and hydrogen directly into “jet fuel range” hydrocarbons using active sites on the catalyst surface, avoiding the traditional first stage of what is known as a reverse water gas shift or electrochemical syngas step that produces carbon monoxide.
Symes says that although aviation biofuels made from crops such as corn or discarded cooking oil have been around since the start of the century, they have made little impact because of the intense energy and land needed to produce them. More efficient processes have brought a second generation of synthetic fuels, but this remains expensive and complicated.
EFFECTIVE RECYCLING
He admits that OXCCU’s answer is “not perfect yet”. The process depends on effectively recycling CO2 – the chief cause of global warming in the first place – that has been created as part of an industrial process. Perfection, he says, would be collecting CO2 directly from the atmosphere, but this is not yet feasible.
“For that reason, we are careful not to brand our solution as carbon neutral, but rather a circular fuel, part of a carbon utilisation cycle,” states Symes. “By doing what we are doing, we are lowering the amount of carbon in the atmosphere. Lower carbon is good. If you wait for perfection, nothing gets done.”
Symes is sceptical about the potential for hydrogen fuel cells, citing the difficulties of producing and storing liquid hydrogen and coming up with entirely new aircraft designs. Instead, liquid hydrocarbons, produced synthetically, can use pipelines, storage facilities, and other existing fossil fuel infrastructure for transportation and distribution.
Moreover, as with other SAFs, e-fuels can be combined with kerosene to create blends. This would allow their gradual adoption as production ramps up. Currently, no commercial flight can operate with a greater than 50% blend of SAF, although demonstration flights have been powered entirely by sustainable fuel.
In June 2023, OXCCU completed a $22.7 million financing round, with investors including United Airlines, Oxford University itself, and several so-called clean-tech investment funds. The start-up was also awarded a £2.8 million ($3.7 million) UK government grant, shared with Sheffield University’s Translational Energy Research Centre and alternative fuels producer Coryton, to demonstrate its process.
Despite the challenges OXCCU will face scaling and commercialising its technology, Symes believes the potential for e-fuels is vast, given they can readily replace traditional carbon-based fuels in aircraft engines.
“In a net-zero world we will still need hydrocarbons,” he says. “We will be selling into a market – oil – that we know is huge. Fossil fuels – coal, gas, and oil – are in higher demand worldwide than ever.”
