Breaking News

The Other Solar Power: How Scientists Are Making Fuel From Sunlight and Air

This story appeared in the July/Aug 2020 situation as “The Other Photo voltaic Power.” Subscribe to Learn magazine for extra tales like this.


Several things to do swell our carbon footprint quite like traveling. A a single-hour flight on a twin-motor jet plane burns just about six,000 kilos of kerosene and adds just about 19,000 kilos of carbon dioxide to the atmosphere. The environmental impact of air journey is so stark that Swedes even have a term for it: flygskam, or flight shame. But what if traveling could be designed zero carbon?

“We have created a solar technological innovation that is able to make liquid fuels applying just two components: solar power and ambient air,” claims Aldo Steinfeld, a renewable power specialist at the Swiss Federal Institute of Technological innovation. “These hydrocarbon fuels release only as significantly carbon dioxide all through combustion as was previously extracted from the air.”

It could seem like alchemy, but the solar refinery Steinfeld has assisted establish in Móstoles, on the outskirts of Madrid, follows some simple chemistry. An array of mirrors identified as a heliostat tracks the sunlight, boosting the sunlight’s depth by a element of 2,500 although reflecting it on to a fifty-foot-large tower.

This stunning beam of mild heats a reactor with a core designed of cerium oxide, an economical compound typically utilised to polish glass. At 2,seven-hundred degrees Fahrenheit, oxygen is liberated from the cerium and taken off, after which water and carbon dioxide captured from the air are injected into the reactor. As the reactor cools, the lowered cerium claws again oxygen molecules from the added materials, leaving a mixture of hydrogen and carbon monoxide identified as syngas. This is funneled into a second reactor, wherever the syngas is transformed into kerosene molecules. In June 2019, the Móstoles refinery announced its initial trickle of gas.

But why turn solar power into gas at all? Even though road and rail transportation are open to electrification, existing battery technological innovation does not pack the punch required to generate large industries these types of as sea freight and air journey. “There is no way all around jet gas for prolonged-haul business aviation,” claims Steinfeld. “Can you consider a Boeing or Airbus traveling trans-Atlantic on batteries? I consider it violates the legislation of physics.”

Photo voltaic kerosene has the prospective to slot into existing world-wide infrastructure for storing, transporting and applying fossil fuels. But it nevertheless cannot compete with them for price tag: It would probable ring up all around $nine for each gallon if it is sold to people. But that charge must fall as the technological innovation enhances in effectiveness and grows in scale. Steinfeld believes that, with a modest raise in latest effectiveness, solar refineries could provide the total world’s jet aviation gas demand with a heliostat array the dimension of Indiana.

This revolution is underway. Past Could, a important airport in the Netherlands announced it would host the world’s initial plant turning atmospheric carbon dioxide into liquid gas. Climeworks — a business spun out from Steinfeld’s lab in 2009 — is offering the modules that will capture carbon dioxide from the air.

And what of our flygskam? “If the jet gas is generated from sunlight and air, then there is very little to be ashamed of simply because the carbon footprint would be zero,” claims Steinfeld. “A true sustainable approach.”


Frank Swain is a science writer centered in Barcelona, Spain.