U scientists harness geothermal energy as renewable source

By By Deborah Rafferty

By Deborah Rafferty

Clean energy is about to get steamy.

U scientists are conducting research to create a more effective way to harness the power of Earth’s natural heat reservoirs. To do this, they have created a new technique to form cracks in rocks to create steam that produces energy.

The U.S. Department of Energy and the U funded the study, which will cost about $10.2 million and will take place during the next five years in Raft River, just north of the Utah-Idaho border.

To harness geothermal energy, wells 1,000 to 6,000 feet deep are dug, where temperatures of hot rocks reach about 300 degrees. Water from underground springs runs through these hot spots, creating steam that comes through cracks in the rocks. The steam turns the turbines in a power plant to generate energy, said John McLennan, an engineer at the Energy & Geoscience Institute and a U engineering research professor.

However, if the wells do not have a considerable number of fissures in the rocks, steam is trapped inside, rendering them useless. Because these wells are expensive to dig, Joe Moore, a geologist from the Energy & Geoscience Institute and U civil and environmental research professor, and his team have created a new process to create more cracks in the rocks to get the most use from the wells.

“The process is designed to create and maintain geothermal power,” Moore said. “If this is successful, you could use geothermal energy instead of coal and gas.”

The first of the two new processes uses cooler water, about 50 to 100 degrees, to create fissures. Because the rocks are at a considerably higher temperature, when the cooler water touches the rocks, they break, forming fissures and allowing the steam to escape, Moore said. The second process will shoot high pressure water at the rocks in hopes of producing cracks from the sheer force.

Geothermal energy is a renewable, nonpolluting resource, McLennan said. It is also sustainable, which means all the water taken out will be put back into the wells. Unlike other alternative energy resources, such as wind and solar, which have to wait for wind and the sun to generate energy, the enormous reserves of geothermal energy can be used 24 hours a day, Moore said.

“The footprint is really quite small,” Moore said. “Typical plants will run for tens of years. It is an absolutely critical research.”

Utah has two geothermal power plants in operation that generate 36 megawatts of power8212;enough energy to power 36,000 houses, about 1,000 houses per megawatt, he said. If the methods are successful, researchers could use this form of energy nationwide.