Turning CO2 into rock – for real

Researchers have successfully turned carbon dioxide into solid rock by injecting it into ancient lava flows

For the first time, scientists have injected carbon dioxide into ancient lava flows and watched it solidify, demonstrating that capturing carbon dioxide from the atmosphere or a power plant smokestack and safely storing it underground may be a realistic way to help reduce greenhouse gas emissions to tackle climate change, according to research published Friday.

Scientists working at the Wallula Basalt Pilot Project in Washington State turned liquefied carbon dioxide into solid rock by injecting the gas into basalt formations. Over a span of about two years, the carbon dioxide solidified into a mineral called ankerite, according to the study conducted by Pacific Northwest National Laboratory researchers. The research was published in the journal Environmental Science and Technology.

“This study further supports the idea that one of the major rock types on the planet—basalts—can be used to store carbon dioxide permanently and safely,” said study lead author Pete McGrail, a carbon dioxide and climate change researcher at PNNL.

Carbon capture and storage may be critical to helping prevent global warming from exceeding 2°C (3.6°F), either by capturing emissions from their source or by directly removing carbon dioxide from the atmosphere, according to the Intergovernmental Panel on Climate Change.

But scientists worry that storing captured carbon underground as a liquid or a gas may not be safe because stored carbon dioxide could explosively leak into the atmosphere through fissures in the earth or be exposed to terrorism risk, creating a climate catastrophe.

To solve that problem, researchers have been studying ways to store carbon dioxide underground as a solid, especially in basalt formations.

Basalt is a volcanic rock that makes up roughly 70 percent of the earth’s surface. When it is exposed to carbon dioxide and water, a chemical reaction occurs, converting the gas to a chalk-like solid material. Scientists previously thought the chemical reaction would take thousands of years to occur, but new research shows it can happen within a few years.

“Basalt storage is unique in the geologic sequestration of carbon dioxide because the principal trapping mechanism is a chemical reaction that locks the carbon dioxide away as a carbonate mineral that can never leak or return to the atmosphere,” McGrail said.

Earlier this year, researchers at the CarbFix project in Iceland were able to pump a geothermal power plant’s carbon dioxide-rich volcanic gases into deep underground but recently formed basalt formations and chemically solidify them in about two years.

Learn more: Scientists Take Another Step toward Safely Burying CO2

See Also

Carbon capture gets cheaper: Least costly carbon capture system to date