The company has completed 3-D modeling and is doing early validation and commercial feasibility testing with the Electric Power Research Institute (EPRI). Demonstration projects could begin as early as 2012.
Luis Cerezo, a technical executive within EPRI’s renewable generation program, says there is significant potential to use GTherm’s single-well design in areas that have been off-limits to geothermal development. “We’re looking at depths of about five kilometers with down-the-hole temperatures of between 250 °F and 300 °F,” says Cerezo. “With this, we’re aiming to produce one megawatt net from each well.”
One megawatt isn’t much, but GTherm envisions a more distributed and scalable model of geothermal generation—from installations of a few megawatts to large clusters of wells totaling hundreds of megawatts.
Thousands of depleted oil and gas wells across the United States and Canada are prime candidates for development, Parrella says. Temperature data is already known in these fields, significantly reducing exploration costs. Parrella is convinced GTherm can deliver clean power for less than 10 cents per kilowatt-hour.
“The approach is definitely beneficial,” says Einstein. But he questions whether GTherm has truly eliminated the risk of triggering seismic events. “The grout must be a viscous liquid before it hardens, so I don’t see why putting it in the well wouldn’t cause similar (seismic) problems. So they’ll have to show it actually works.”