Posted by: Footler PJ13 OCT 2011
Removing unwanted carbon produced by transport, energy production and industrial processes is known as sequestration. Planting more trees, stimulating the growth of plankton in the oceans or, as is done in Norway, replacing the natural gas pumped out of wells with carbon dioxide are among the many techniques so far suggested to achieve it. The goal is to store the carbon so that it cannot easily escape back into the atmosphere, thus achieving a net zero carbon footprint or carbon neutrality. This is increasingly seen as good corporate or state social responsibility.
CarbFix, a joint American and Icelandic venture, has just started a project at Hellisheidi in south-west Iceland, near Reykjavik Energy’s geothermal power stations, to assess the viability of storing polluting carbon underground by artificially creating seams of limestone. Iceland already uses a high proportion of renewable energy resources — over 99 per cent of electricity production and almost 80 per cent of total energy comes from hydropower and geothermal sources — and the short-term aim is to help the geothermal power stations to become truly carbon neutral. The project organisers are cautiously optimistic about the wider potential if the experiment goes well.
Carbon dioxide dissolved in water will be pumped down into the porous volcanic basalt rock that makes up most of Iceland’s landmass. This “seltzer water” will be forced into the pores and react with calcium in the basalt to form calcium carbonate or limestone so that it cannot escape back into the atmosphere.
Basalt is one of the world’s most abundant rocks. Indeed, CarbFix manager Juerg Matter notes: “My vision for carbon capture and storage is offshore, below the sea. The whole ocean floor is basalt below the sediments.” He suggests that the technique, if successful, could be carried out on a massive scale to aid the fight against harmful climate change.