Iceland is now using its natural environment to turn greenhouse gases into solid rock, a process that normally takes centuries in the natural world. At a power plant Iceland, the transformation now takes a matter of months. In research detailed recently in Science, a process is described in which carbon dioxide is dissolved in water, and then injected into basalt rock. The ensuing chemical reaction mineralizes the gas. Basalt rock is extremely common worldwide, so theoretically the process in Iceland offers some hope to the world in general for dealing with excessive carbon emissions in the future.
The carbon injection site is at the Hellisheidi geothermal plant near Reykjavik. The project, called Carbfix, began in 2007, and scientists around the world have since lauded the research. The lead author of the recent paper is Martin Stute, a research scientist from Columbia University. Pete Mcgrail, a scientist also studying carbon sequestration at the Pacific Northwest National Lab, says the process confirms many years of lab tests suggesting mineralization could happen relatively quickly.
The project does have some limitations which may mean there is some time yet before use of this method becomes widespread. At Hellisheidi, the process costs 30 dollars per ton of carbon dioxide, a relatively low cost since the company was already building the necessary infrastructure in order to remove sulfurous gases from the area. To put the process into action in other locations however, it may cost up to triple that amount. Carbfix researchers also note that 25 tons of water are also required for every ton of carbon processed – a large amount which might prove prohibitive in many parts of the world.
Similar projects have explored storing carbon under layers of impermeable rocks, such as sandstone, but these efforts have left concerns that carbon dioxide would leak back into the atmosphere. The Carbfix project solves this by solidifying the gas in place. The C02 was tagged with carbon-14 in order to track whether any was leaking through the surface or into nearby water, and none was found to have escaped.
This research opens the possibility of quickly and safely storing large quantities of C02. Basalt is found on every continent, and the oceanic crust below the seafloor is entirely composed of basaltic rocks. Once cost and efficiency issues are dealt with, this process could become a viable option around the world.