Scientists found a way to turn our carbon emissions into rock
Earlier this year, a project in Iceland reported an apparent breakthrough in the safe underground storage of the principal greenhouse gas, carbon dioxide — an option likely to be necessary if we’re to solve our global warming problem.
The Carbfix project, run by a leading Icelandic producer of geothermal power, Reykjavik Energy, announced that it had successfully injected 250 tons of carbon dioxide, dissolved in water, into an underground repository of volcanic rocks called basalts — and that the carbon carbon dioxide hadn’t just stayed there. No — it was way better than that. Instead the carbon dioxide had apparently become one with the basalt, undergoing a fast chemical reaction and forming a type of rock called a carbonate in two years’ time.
That’s a big deal because it means the gas would not escape back to the atmosphere again even if the underground repository were somehow compromised. And now, a group of American researchers has taken the science even farther, once again suggesting that storing carbon dioxide stripped from industrial processes, or sucked from the atmosphere, in basalt rocks may be a key part of the solution to climate change.
Peter McGrail of the Pacific Northwest National Laboratory, a branch of the Department of Energy, and his colleagues were also working on storing carbon dioxide in basalts, based upon small scale laboratory experiments showing the gas does bind with the rock. And they, like the Carbfix project, were ready to scale up and perform an actual injection, in this case 1253 meters deep into basalts from the Columbia River region of Washington State.
In their results reported Friday in the journal Environmental Science & Technology Letters, they go beyond the Carbfix project in several key ways, McGrail said. First, they injected carbon dioxide in its fluid, supercritical form, which is most likely to be how it is received and transported from industrial projects. And second, after two years had passed, they took core samples of the rocks, using a battery of tests to prove definitively that the CO2 had indeed turned into a carbonate rock called ankerite, comprised of calcium, carbon, oxygen, iron, magnesium, and manganese..
In effect, what the researchers in both Iceland and Washington State were accomplishing was a high speed version of the geological process known as “weathering,” in which carbon dioxide very slowly becomes locked away in rock layers..
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