Turning CO2 Into Stone
A power plant in Iceland is set to become the first in the world to try turning its carbon dioxide emissions into solid minerals underground, starting this September.
In an $11 million pilot project, Reykjavik Energy will capture CO2 from its plant, dissolve the gas in water and inject it deep into volcanic basalt nearby. Over the nine-month study, some 2,000 tons of greenhouse gas will be treated.
At the start of the demonstration, Reykjavik Energy and its partners–Columbia University’s Earth Institute, the University of Iceland and the Centre National de la Recherche Scientifique in France–will hold a conference on carbon sequestration in Iceland.
Ninety percent of Iceland is made up of basalt, a rock that reacts naturally with carbon dioxide to form a harmless, solid carbonate–basically, limestone. By speeding up the process, called carbon mineralization, some scientists see a potentially safer alternative to pumping CO2 into empty oil reservoirs and other porous spaces below ground, where leaks could one day occur.
Juerg Matter, a geochemist at Lamont-Doherty Earth Observatory involved in the research, said, “If CO2 is dissolved in water, it is less mobile – it can’t go out. It then reacts with basalt to form carbonate.”
Three conventional storage projects that do not employ mineralization are already underway in Canada, Algeria and in the North Sea, where companies are injecting about one million tons of carbon dioxide a year below ground. The North Sea project—run by a Norwegian oil company–has stashed 10 million tons in a sandstone reservoir below the seabed. Another researcher at Lamont, Scott Nooner, is part of a team of scientists monitoring the site.
Reykjavik Energy has spent the last two years building a plant to capture and treat its CO2 emissions. The company is paying for about 45 percent of the project, with Columbia and its partners picking up the rest.
Only a small part of the CO2 sent down is expected to mineralize during the nine-month study period; the reaction could take years to complete. Another type of rock that Matter and his colleagues have studied, peridotite, is able to break down CO2 much faster, but that research has not yet reached a commercial stage.