The Promise and Potential of Turning CO2 to Stone
On a planet where global concentrations of atmospheric carbon dioxide are higher than at any other time in human history, the need for game-changing solutions is escalating.
Carbon capture and storage (CCS) technologies, which remove tons of carbon dioxide from industrial processes and store them away so they can’t add to the climate crisis, are gaining attention and support. A recent review paper details how CCS can contribute to a long-term reduction in atmospheric carbon dioxide levels, and work to meet the caps on human-caused global warming written into the 2015 Paris Climate Agreement.
At Columbia University’s Lamont-Doherty Earth Observatory, David Goldberg is on the forefront of developing technologies with the ability to capture CO2 and turn it into stone. He has been involved in recent projects that have demonstrated that when you inject CO2 and water into basalt rock, the silicate material takes up the gas and turns it into carbonate rock. If this natural process can be enhanced, scientists believe it could be a valuable tool to solve the crisis-level airborne carbon dioxide in Earth’s atmosphere.
Under an Iceland-based pilot project called CarbFix — designed and carried out with Columbia leadership — researchers proved that basaltic rock units react rapidly with CO2 captured from a power plant. The team mixed gasses generated by the Hellisheidi geothermal power plant with water and reinjected the solution into the volcanic basalt below. In nature, when basalt is exposed to carbon dioxide and water, a series of natural chemical reactions takes place, and the carbon precipitates out into whitish, chalky minerals — carbonates. Before CarbFix, no one knew how fast this might happen if the process were harnessed for carbon storage. Previous studies had estimated that in most rocks, it would take hundreds or even thousands of years. In the basalt below Hellisheidi, 95 percent of the injected carbon was fixed as carbonates within less than two years. This proof of concept was an important step.
“Now it’s all about scale,” said Goldberg.
CarbFix currently injects and stores about 10,000 tons of CO2 per year in solid carbonate minerals, below the land surface near the power plant. Looking to scale-up this process, Goldberg and colleagues seek to capture millions of tons of CO2 from more distant industrial sources — such as fossil fuel power plants, manufacturing plants, and refineries — and inject them into submarine basalts off the coast of Washington and Oregon.
With the Solid Carbon project, the team aims to conduct offshore geophysical surveys, study the basalt reservoir, and set up a pilot injection and monitoring experiment at a site in Cascadia, at approximately the scale of the CarbFix project in Iceland.
“The big idea is to get this demonstration project funded and completed,” said Goldberg. “But the even bigger picture is to then scale this up and establish a climate solution that allows for direct capture of CO2 from ambient air with permanent offshore storage. So, once these carbon capture and undersea technologies are successfully demonstrated together, we can multiply the process in many locations and really make a difference.”
Today’s announcement that the “Solid Carbon” capture and storage project has been selected by the MacArthur Foundation as one of the highest-scoring proposals in its 100&Change competition offers hope. As one of the top 100 projects, Solid Carbon will be featured in an online database of high-impact ideas. Goldberg hopes this will help to attract the support needed to fund a next-level carbon capture and storage demonstration. The program is designed to connect philanthropists with vetted, high-impact projects in need of funding.
From the Top 100 list, 10 finalists will be selected this spring, and the winner of the $100 million grant will be announced in the fall.