Geothermal engineering gets a boost

The Dept. of Energy will invest $43.1 million in 21 enhanced geothermal projects.

By Consulting Specifying Engineer Staff October 8, 2008

The Dept. of Energy (DOE) announced on Oct. 6 that it will invest up to $43.1 million over the next four years in 21 research, development, and demonstration projects involving enhanced geothermal systems (EGS).

EGS technologies employ rock fracturing techniques in high-temperature geological formations deep underground, and they can be used to either create a geothermal reservoir of hot water or steam where none existed before or to extend and enhance an existing geothermal reservoir. The technology typically involves the injection of water at high pressures to fracture the rock. The awards will given to companies and universities under two topic areas—systems demonstrations and technology research and development (R&D)—and include a record 13 first-time recipients. Combined with private cost-share investments, up to $78 million will be invested in these projects.
DOE will invest $3.7 million in four systems demonstration projects, all of which will attempt to increase power production from existing geothermal reservoirs, including The Geysers reservoir in northern California, about 72 miles north of San Francisco; the Brady geothermal field in Nevada, about 50 miles east of Reno; the Raft River geothermal project in southern Idaho, about 200 miles southeast of Boise; and a fourth undisclosed location. The success of these projects could result in more than 400 MW of new generating capacity within the next five years.
DOE also will invest up to $8.7 million in 17 R&D projects, which will address aspects of geothermal reservoir creation, management, and use at temperatures up to 572 F and depths as great as 6.2 miles. The technologies include computer models and tools for characterizing the enhanced geothermal reservoirs—such as seismic monitors, chemical techniques, and devices that would be lowered to the bottom of a borehole—as well as electronic systems and submersible pumps designed to operate in the high-temperature geothermal well environments. In addition, one project will investigate the use of “proppants,” which are small particles mixed with the fracturing fluid to help hold fractures open.