For 20 years, Los Alamos National Laboratory researchers have wanted to tap the Earth's heat. Known as "hot dry rock" heat mining, the strategy involves drilling two holes, forging a connection between them thousands of feet deep in the earth, then pumping water down one hole. Water coming back up the other hole should be hot enough to generate large amounts of electricity. The scheme avoids the pitfalls of other geothermal plants, which use limited or caustic underground water reserves.
In mid-February, the California Energy Commission handed Los Alamos its first contract, for $230,000, to test the idea in a region of hot underground rocks near Clearlake, Calif. The goal is to have a commercial-size plant operating in Clearlake by the end of the decade. The study will help answer two big questions: Whether enough water will travel back to the surface, instead of leaking away underground, and whether the water will be hot enough to generate sufficient power.