Utilities Tap Heat from Earth's Core

BOISE, Idaho - Hot water bubbles and steams out of the ground in many parts of Idaho, and resourceful residents use it for everything from heating their cities to raising alligators.

Early residents used the area's hot springs to bathe, wash and cook. Now Idaho's hot springs and underground reservoirs heat several buildings in Boise, including the capitol, a neighborhood of stately homes, a Veterans' Administration hospital, several greenhouses and a coral business.

As the cost of energy from conventional sources increases, various advocates of using natural hot water power, known as geothermal, are hoping to expand its uses. An Idaho developer is working on a plant in southern Idaho that would draw even hotter water from deep under the earth and convert it to electricity.


In Boise, the state Water Resources board has imposed a moratorium until 2008 on new use of the geothermal aquifer because water levels dropped several years ago. After the city water system installed a system to inject the water back into the ground, water levels stabilized.

The level of the aquifer that serves Boise is closely watched by the Idaho Department of Water Resources, which administers the water rights for all of the state.

Kent Johnson, an engineer who works for the city of Boise, thinks it's time for more users, like Boise State, to sign on.

"It's a renewable, valuable resource that we should be using," Johnson said. "It saves on fossil fuel, we're not burning anything, so we're not affecting the air quality."



Used since ancient times

Geothermal heat has been used since ancient times in the volcanic regions of the world, including parts of Asia, Europe, and North America.

Boise, Idaho's largest city, developed its natural hot springs in 1890 - around the time Idaho gained statehood - when a local company drilled and found water at about 172 degrees, said Arthur Hart, a Boise historian. A long row of elegant homes, Warm Springs Avenue, was built to use it.

"Geothermal heat is one of the most valuable resources in Idaho," said Leroy Headlee, who uses it to raise coral at his Geothermal Aquaculture Research Foundation in Boise. "It's like free energy."

The city of Boise also operated a large, luxurious hot-water bathing complex, the Natatorium, until it was damaged in a storm in the 1930s.

Over the years, enterprising Northwesterners have used hot springs in a variety of ways. A farmer in Hagerman uses the hot water to raise alligators for meat and hides, and sturgeon for caviar. Klamath Falls, Ore., another city with a long geothermal tradition, uses its natural hot water to melt snow off sidewalks and bridges.



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