Electricity with Dry Rocks

There are places where there is underground heat but no nearby water. Engineers are finding ways to bring water to these hot spots. Then we will be able to use the geothermal energy there.

Hot dry rock, or HDR, systems are one way to do this. Scientists in Los Alamos, New Mexico, began building the first HDR system in 1970. The system used three wells, each about 2 miles (3 km) deep. Engineers sent cold water down the first well. The cold water hit the hot rocks and broke them. The water turned hot. Some of it turned to steam. The steam and water then rose up through the other wells and turned turbines.

This drawing shows a hot dry rock system that uses a heat exchanger. There, hot water warms a liquid that is used to generate electricity.View Larger Image

Rosen Publishing