Researchers in Iceland are trapping CO2 by turning it into rock.
Carb Fix is a pilot program taking place in Iceland in which researchers from Columbia University's Lamont-Doherty Earth Observatory have developed a way to capture and store carbon dioxide by turning it into stone.
Their technique is described in an article published in the Science journal under the name "Rapid carbon mineralization for permanent disposal of anthropogenic carbon dioxide emissions." They inject CO2 into volcanic rock and this triggers a reaction that rapidly forms new carbonate minerals, potentially locking gas away forever.
The technique is still not ready to become commercially viable, but "this is a great step forward,” says Sally Benson of Stanford University in Palo Alto, California, a geologist unaffiliated with the project.
Carbon capture and storing (CCS) has been used in dozens of pilots. According to Science Magazine very few have been scaled up, wing to prohibitive costs of about $50 to $100 per ton of CO2 sequestered.
One of CCS biggest concerns is leakage. In 2006 Icelandic, US and French scientists proposed injecting the CO2 into underground layers of basalt, the rock that underlies Earth's ocean and parts of continents. Basalt contains minerals that react with CO2 and form carbonate minerals such as calcite.
The CarbFix project was launched 25 km east of Reykjavik with the intention of injecting underground basalt that bubbles form cooling magma. In 2012 scientists injected 220 tons of CO2 into layers of basalt between 400 and 800 meters below the surface.
This provides a valuable way to undo some of the damage caused by fossil fuel burning. Over 95% of the injected CO2 was mineralized in less than two years, and the resulting carbonate minerals are stable so they would avoid the risk of leakage.
"This means that we can pump down large amounts of CO2 and store it in a very safe way over a very short period of time," Martin Stute, a hydrologist at the Lamont-Doherty Earth Observatory and a coauthor of this week's study, said in a statement. "In the future, we could think of using this for power plants in places where there’s a lot of basalt and there are many such places."
Bigger field tests are needed to confirm that such high amount of the injected carbon is mineralized. Another complication is the amount of water needed to become viable on a larger scale. The process requires 25 tons of water for every ton of CO2.
But CarbFix scientists acknowledge the biggest obstacle of CCS in basalt is funding. Power companies have little incentive to develop it. “Without a price on carbon emissions, there’s no business case,” admits Juerg Matter, a geologist with CarbFix at the University of Southampton in the United Kingdom.
He hopes policy makers will create such incentive, otherwise these type of projects will fail to commercialize. Meanwhile, the success in Iceland is welcome as a development as the field has received some good news.