Swiss Researchers Say They Can Produce SAF from Air

 - November 4, 2021, 5:17 PM
This solar reactor demonstrator on the roof of the machine laboratory at ETH Zurich, uses a sun-​tracking, parabolic reflector to concentrate the sunlight that powers the reaction which eventually turns atmospheric carbon dioxide and water into drop-in hydrocarbon fuels. According to the researchers, the reaction can be tailored to produce specific fuels. (Photo: Alessandro Della Bella/ETH Zurich)

Researchers in Switzerland say they have developed technology to produce sustainable aviation fuel using nothing but air and sunlight. In an article, "Drop-in Fuels from Sunlight and Air" (Schäppi, R. et al.), published this week in the journal Nature, the team at public research university ETH Zurich, described how they have operated a solar-powered mini-refinery on the roof of one of the school’s laboratories for the past two years to demonstrate the three-stage thermodynamic process by which the fuel is created.

First, a direct capture unit extracts carbon dioxide and water from ambient air. The next phase converts these elements—CO2 and H2O—into CO and H2 in a specific ratio known as syngas. The final step converts the syngas into liquid hydrocarbons. By tailoring the syngas composition, the researchers were able to produce either drop-in synthetic methanol or kerosene that would be fully compatible with existing infrastructure and fuel supplies.

The test unit is intended to prove the concept on a very small scale and can only produce less than two ounces of fuel per day. Project leader Aldo Steinfeld, a professor of renewable energy carriers at ETH Zurich, noted that the energy efficiency on the solar reactor still requires improvement. But he believes that the process, once handed off to the university’s industrial partners, could be scaled up to commercial production in arid environments where sunlight is plentiful.