Scientists plan to store CO2 deep underground

In a novel way to fight global warming, scientists are trying how they could remove excess carbon dioxide from the atmosphere and store the gas deep under the sea bed where it can cause no trouble.

Researchers at the University of Iceland are studying the possibility of sequestration of carbon dioxide in basalt, a common extrusive volcanic rock that makes up most of the world's oceanic crust.

Sequestration is the carbon-capturing method which involves injecting the gas directly into underground geological formations.

Oil fields, gas fields, saline formations, unminable coal seams, and saline-filled basalt formations have been suggested as storage sites. Sigurdur Gislason, of University of Iceland, who is is leading an international team of scientists on the 'Carbfix Project' for an Icelandic geothermal power plant, presented his findings today at the annual Goldschmidt Conference at the University of Tennessee, Knoxville. Gislason's project aims at pumping carbon deep underground in southwest Iceland where it will mix with minerals and become rock.

The project involves capturing and separating flue gases at the Hellisheidi Geothermal Power Plant in Hengill, transporting the gas, dissolving it in water, and injecting it at high pressures to a depth between 400 and 800 meters into a thick layer of basalt.

Then the researchers will verify and monitor the storage.

"If successful, the experiment will be scaled up and can be used wherever carbon dioxide is emitted," said Gislason.

"Currently, carbon may be captured as a byproduct in processes such as petroleum refining. It can be stored in reservoirs, ocean water and mature oilfields."

Carbon sequestration is currently the most promising way to reduce greenhouse gases and Gislason's project is aimed at finding a storage solution that is long lasting, thermodynamically stable and environmentally benign.

The researchers said that the storage of CO2 as solid magnesium carbonates or calcium carbonates deep underground in basaltic rocks may provide a long-term and thermodynamically stable solution.

However, many experts fear that CO2 may leak over time.