Fuel made from sunlight and air

Researchers at the Swiss Federal Institute of Technology in Zurich ETH have achieved a breakthrough: They have developed a technology via which CO2-neutral fuel can be produced from sunlight and air. On Thursday, they presented their innovative technology under real conditions. Their new solar-powered mini refinery is located on the roof of ETH’s Machine Laboratory building in Zurich. An additional pilot plant is also being showcased in Madrid. Aldo Steinfeld, Professor of Renewable Energy Carriers at ETH Zurich, commented in a press release: “This plant proves that carbon-neutral hydrocarbon fuels can be made from sunlight and air under real field conditions”.

At the moment, the mini refinery in Zurich is producing around one deciliter of fuel per day. However, the technology is soon to be scaled-up to industrial production volume, according to Philipp Furler, a former doctoral student at ETH who helped to develop the solar reactor, whose focus has now switched to preparing the technology for industrial implementation in his role as co-founder of the ETH spin-off Synhelion. “A solar plant spanning an area of one square kilometer could produce 20,000 liters of kerosene a day”, Furler explains. “Theoretically, a plant the size of Switzerland – or a third of the Californian Mojave Desert – could cover the kerosene needs of the entire aviation industry. In a report by SRF, Furler additionally reveals that the Italian oil and gas company Eni is intending to invest in the technology. Together with Synhelion, Eni is planning to put into operation the first commercial plant by 2025, although its exact location is not yet clear.

For the production of the fuel, technology developed by the ETH spin-off Climeworks is initially used to extract CO2 and water from the air. In the next step, the CO2 and water are fed into the Synhelion solar reactor and subjected to solar-thermochemical splitting. The product is syngas, a mixture of hydrogen and carbon monoxide, which can then be processed into kerosene, methanol and other hydrocarbons. The fuels produced in this way are C02-neutral: during combustion, these fuels release a volume of C02 equivalent to that extracted from the ambient air in the production process.