Scientists create a solar-powered tower that makes carbon-neutral jet fuel

ZÜRICH, Switzerland — Scientists have created a carbon-neutral jet fuel that comes from a very eco-friendly source — a solar-powered tower.

Researchers in Switzerland say the futuristic fuel uses water, carbon dioxide, and sunlight to power jet engines. The team is the first to produce the fuel in a power generator rather than a lab.

The amount of synthetic jet fuel it emits when it combusts in a plane’s engine equals the amount consumed during its production in a solar plant, thus making it carbon-neutral. The fuel will be even greener if the team can capture carbon dioxide from the air in the not-too-distant future and use it in the fuel.

The solar-made kerosene, or jet fuel, is fully compatible with the existing way fuel is stored, distributed, and used in a plane’s engine. Researchers add they can also blend it with fossil-derived kerosene.

How does the ‘all-in-one’ tower work?

In 2017, the team started scaling up their design and built a solar-powered production plant at IMDEA Energy Institute in Madrid, Spain. It consists of 169 sun-tracking reflective panels that redirect and concentrate solar radiation into a solar reactor on top of a tower.

Schematic of the solar tower fuel plant
Schematic of the solar tower fuel plant. (Credit: ETH Zurich)

That solar energy then drives oxidation-reduction (redox) reaction cycles in the reactor, which contains a porous structure made of ceria, a white or yellow heavy powder. The ceria – which is a reusable component in this process – converts water and carbon dioxide entering the reactor into syngas, which is combination of hydrogen and carbon monoxide.

The syngas then enters a gas-to-liquid converter where the tower processes it into liquid hydrocarbon fuels, including kerosene and diesel. Over a nine-day period, researchers discovered that the plant’s energy efficiency was four percent, but the team is working to boost that to 15 percent.

‘Setting a technological milestone’

Airplanes are responsible for around five percent of global emissions and their engines run on kerosene or jet fuel, a liquid hydrocarbon fuel derived from crude oil. No clean and effective way of flying planes currently exists.

Solar reactor
Solar reactor after exposure to concentrated solar radiation. (Credit: IMDEA Energy)

“We are the first to demonstrate the entire thermochemical process chain from water and CO2 to kerosene in a fully-integrated solar tower system,” says study corresponding author Professor Aldo Steinfeld from the Swiss Federal Institute of Technology in Zürich in a media release.

“With our solar technology, we have shown that we can produce synthetic kerosene from water and CO2 instead of deriving it from fossil fuels. The amount of CO2 emitted during kerosene combustion in a jet engine equals that consumed during its production in the solar plant,” Steinfeld says.

“That makes the fuel carbon neutral, especially if we use CO2 captured directly from the air as an ingredient, hopefully in the not-too-distant future.”

“This solar tower fuel plant was operated with a setup relevant to industrial implementation, setting a technological milestone towards the production of sustainable aviation fuels,” Steinfeld concludes.

The team describes the new process in the journal Joule.

South West News Service writer Gwyn Wright contributed to this report.

Comments

  1. So what! Co2 is the fuel used by plants to live.. no Co2 no plant life, and no food for humans or almost anything else.

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