Swiss team demonstrates carbon-neutral fuel made from sunlight and air

14 Jun 2019

Still from ‘Carbon-neutral fuel made from sunlight and air’. Image: ETH Zurich/YouTube

Researchers in Switzerland believe they have created a potentially revolutionary carbon-neutral solar refinery to produce liquid fuels.

In the race to develop alternative, renewable fuel sources, a team of scientists and engineers from ETH Zurich has unveiled the development of a technology that can produce synthetic liquid fuels. Most importantly, it releases as much CO2 during their combustion as what would have been extracted from the air for their production.

CO2 and water are extracted directly from ambient air and split using solar energy, yielding something called ‘syngas’. This mixture of hydrogen and carbon monoxide is subsequently processed into kerosene, methanol or other hydrocarbons. Due to their nature, they could be immediately used in existing global transport systems and replace non-renewable fossil fuels.

“This plant proves that carbon-neutral hydrocarbon fuels can be made from sunlight and air under real field conditions,” said Aldo Steinfeld, head of the research group behind this technology. “The thermochemical process utilises the entire solar spectrum and proceeds at high temperatures, enabling fast reactions and high efficiency.”

The mini-refinery built on the roof of the university to put the theory into practice has so far proven that the technology is feasible, even within a country where sunshine is not constant. It currently produces around one decilitre of fuel per day, with Steinfeld and his group already working on a large-scale test of their solar reactor in a solar tower near Madrid.

Philipp Furler, director of Synhelion – a spin-off founded to commercialise this technology – and a member of the research group, explained what a large-scale plant could achieve.

“A solar plant spanning an area of one square kilometre could produce 20,000 litres of kerosene a day,” he said.

“Theoretically, a plant the size of Switzerland – or one-third of the Californian Mojave Desert – could cover the kerosene needs of the entire aviation industry. Our goal for the future is to efficiently produce sustainable fuels with our technology and thereby mitigate global CO2 emissions.”

Colm Gorey was a senior journalist with Silicon Republic