In conventional geothermal plants, water and steam heated by hot rocks deep underground drive turbines in a power plant. The water is then pumped back underground to be heated up again.
The new technology would use carbon dioxide instead of water. This approach has several potential advantages. By eliminating the need for water, it increases the prospects for geothermal projects in dry areas. And computer simulations show that CO2 could produce twice the electricity from a given area that water produces, says Martin Saar, a professor of geology and geophysics at the University of Minnesota. Saar is cofounder of Heat Mining, a company that plans to test this technology in a small power plant that it will build next year.
Interesting idea. Not sure it is going work, but similar technologies are emerging. One of them will work. :)