According to scientists in Switzerland, aeroplane fuel can be made out of just sunlight and air. On the roof of ETH Zurich University, engineers are testing whether a new system of fuel generation can work in the real world.
In just three steps, the carbon neutral fuel is created. First, an air capture unit absorbs CO2 and water from the air. Second, a solar unit extracts energy from the sun, which then turns these elements into a mixture of carbon monoxide and oxygen (called syngas). Lastly, the syngas is turned into a liquid which is used as fuel, which is being called “solar kerosene”.
“This plant successfully demonstrates the technical feasibility of the entire thermochemical process for converting sunlight and ambient air into ‘drop-in fuels’,” Aldo Steinfeld, Professor of Renewable Energy Sources at ETH Zurich, explains. “The system operates stably under real-world solar conditions and provides a unique platform for further research and development.”
According to Steinfeld, the technology is now ready to be applied in the real world, but it will need funding to get there, especially as the carbon neutral fuel would be more expensive to produce than regular kerosene. An estimate suggests that the fuel would cost €1.20-2.00 per litre if it were produced on an industrial scale, in comparison to kerosene costing only €0.40 per litre.
As for production sites, desert regions with lots of sunshine seem to be particularly suitable. “Unlike with biofuels, whose potential is limited due to the scarcity of agricultural land, this technology enables us to meet global demand for jet fuel by using less than one percent of the world’s arid land and would not compete with the production of food or livestock feed,” explains Johan Lilliestam, a research group leader at the Institute for Advanced Sustainability Studies (IASS Potsdam) and professor of energy policy at the University of Potsdam.
However, the EU does not currently fund solar fuels, so Lilliestam suggests that airlines take charge themselves in order for them to become mainstream.