Rapid carbon mineralization for permanent disposal of anthropogenic carbon dioxide emissions:
Scientists in Iceland say they have discovered a new way to convert carbon dioxide into rock. Like many other carbon capture and storage pilot projects, this one – called CarbFix – faces high hurdles in terms of costs and technology, however, CarbFix’s latest results are a great step forward towards locking the gas underground forever.
Published in Science, the research shows that injecting CO2 into layers of basalt (dark volcanic rocks underlying Earth’s oceans and parts of some continents) triggers a reaction that rapidly forms new carbonate minerals. The project began back in 2006 when Icelandic, U.S. and French scientists launched the CarbFix experiment 25 kilometers east of Reykjavik, intending to dose Iceland’s abundant underground basalt with CO2 that bubbles from cooling magma underground and is collected at a nearby geothermal power plant.
In 2012, they injected 220 tons of CO2 – with heavy carbon for monitoring and some extra water mixed in – into layers of basalt between 400 and 800 meters below the surface. After about a year and a half, the pump inside a monitoring well kept breaking down, which engineers discovered was due to calcite buildup that bore the heavy carbon tracer that marked it as a product of carbonation. Measurements of dissolved carbon in the groundwater suggested that more than 95% of the injected carbon had already been converted into calcite and other minerals.
The speedy carbonation “means this method could be a viable way to store CO2 underground—permanently, and without risk of leakage,” explained Juerg Matter, a geologist with CarbFix at the University of Southampton in the United Kingdom. Bigger field tests are needed, and many challenges remain before the technique could be widely used – not the least of which is a lack of incentive for power companies to incorporate CCS. In the meantime, though, the success is a welcome development.