In Austria, scientists found a way to turn captured CO2 and water into climate-neutral methane

Researchers in Austria report that methane can be produced through an unanticipated process that combines captured carbon dioxide and water, a result that could offer a cleaner source of a fuel still used across industry.

The work suggests one possible way to both soak up excess renewable power and turn planet-warming CO2 into something useful.

What happened?

Vienna University of Technology reported that scientists from the school and the University of Innsbruck found an unexpected route for producing methane in a climate-neutral way. The method uses electricity with water and previously captured CO2 to assemble the fuel.

Professor Günther Rupprechter said the project looked to develop a streamlined system that could handle both starting materials in a single process.

"For us in the [Materials for Energy Conversion and Storage] research cluster, it was clear that it would be much more elegant to develop a process that accomplishes two things at the same time: first, splitting carbon dioxide to provide carbon, and second, splitting water to simultaneously provide 'green' hydrogen," he said.

Working with nickel on yttria-stabilized zirconia, the researchers found that zirconia does more than just move oxygen ions.

First author Christoph Thurner explained: "When we apply an electric voltage, carbon is initially deposited on the nickel atoms — that was what we expected. But part of this carbon then migrates further onto the zirconia surface, where a reactive carbon-zirconium compound is formed. As soon as small amounts of water vapor come into contact with this compound, it reacts again, and methane is formed."

Why does it matter?

Methane is a powerful heat-trapping gas when it is in the atmosphere, but it is also a major industrial fuel. A process that makes methane from captured CO2, water, and renewable electricity could offer a lower-pollution option while also storing surplus clean energy for later use.

That is especially important because solar and wind power do not always line up neatly with energy demand.

Researchers said the approach may be especially valuable when solar generation overshoots demand and photovoltaics produce more electricity than is needed. In that case, the surplus power could be stored by converting it into fuel instead of wasting it.

What are people saying?

In discussing the discovery, the researchers cast it as a streamlined approach to making renewable fuel.

Rupprechter said the idea was to pull carbon from CO2 while also producing green hydrogen, or hydrogen made with renewable electricity, from water in a single process.

The group also highlighted that the mechanism was not what they expected. They called the finding "a surprise." 

"The idea of converting carbon dioxide into product gases is not new," Rupprechter said. "Carbon dioxide can be split and then reacted with hydrogen. However, the question then is: Where does the hydrogen come from?"

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