Using CO2 to Extract Geothermal Energy

Carbon dioxide captured from power plants could make geothermal energy more practical.
Carbon dioxide generated by power plants may find a second life as a working fluid to help recover geothermal heat from kilometers underground. Such a system would not only capture the carbon dioxide and keep it out of the atmosphere, it would also be a cost-effective way to use the greenhouse gas to generate new power.

Backers of this as-yet-unproven concept secured a big endorsement and much-needed cash with the U.S. Department of Energy's recent award of $338 million in federal stimulus funds for geothermal energy research. Some $16 million of the funds will be shared by nine carbon dioxide-related projects led by Lawrence Berkeley National Laboratory and other national labs, Sunnyvale, CA-based combinatorial chemistry firm Symyx Technologies, and several U.S. universities.
The idea: Carbon dioxide that's cycled through hot regions kilometers underground can efficiently bring heat to the surface, where it can be used to generate electricity. The likelihood is that the process would leave lots of carbon dioxide underground, and thus out of the atmosphere, according to Symyx project leader and materials scientist Miroslav Petro. "You're sequestering CO₂ and at the same time generating power from it."