Low Temperature Geothermal Electricity Breakthrough

www.technologyreview.com...

A large share of the geothermal resources suitable for power generation--those with temperatures higher than 300°F--are deep underground, beyond the reach of current technology. Lower-temperature resources, which are common across the United States, are generally used for heating, but could be a bountiful source of power as well, if researchers were able to find an economical way to convert them into electricity.

Engineers at the United Technologies Research Center (UTRC), a unit of United Technologies based in East Hartford, CT, say they have developed a low-cost system that can utilize low-temperature geothermal resources. The technology could be particularly useful in generating electricity from waste hot water generated at oil and gas wells.

The modular, 200-kilowatt power plant from UTRC can convert temperatures as low as 165°F into electricity. The technology is similar to steam engines, except that steam or hot water vaporizes a hydrofluorocarbon refrigerant that drives the turbine. And the refrigerant has a lower boiling point than water. "It's hard to run a steam engine at 165 degrees [Fahrenheit]," says Bruce Biederman, who leads the project at UTRC. "The size of the equipment would be enormous and your turbine would be very poor in efficiency."

This is simply a huge breakthrough. Most geothermal systems in the world are limited to specific geographical regions of the world where magma bubbles out near the surface.

This, by contrast, can be used nearly anywhere on earth! I'm not too sure how feasible it will be to convert old houses over, but if this technology works as expected, I can see how in some places(Japan for instance) they will start to mandate that each new building have at least one Geothermal generator attached to the house(for a grid-tied setup).

[edit on 22-9-2006 by sardion2000]