Geothermal: Hot or not? (Simmering for a century) — High Country News

In 1892, the people of Boise, Idaho, came up with an idea for staying warm without burning the usual coal or wood: They piped water from nearby hot springs into their own homes to heat them, as well as into the local Natatorium, an indoor swimming pool and spa.

Indigenous peoples had been using hot springs’ natural warmth for millennia, but Boise was probably the nation's first settler-colonial city to pipe this energy directly into its homes. Today, Boise's municipal utility employs a similar method to heat its downtown buildings .

Boise is harnessing a simple, lower-temperature form of geothermal energy found relatively close to the Earth's surface. It's tapped elsewhere in the West, warming swimming pools and sidewalk snow-melting systems — even an alligator farm in Colorado — as well as greenhouses and a prison in Utah. The Earth's heat can also be harnessed to create steam to turn a turbine and generate electricity, without burning dirty fossil fuels or sparking dangerous nuclear reactions. Geothermal doesn't flag when the sun sets or the wind stops blowing, and it takes up far less space than other clean energy sources. And it won't be exhausted until the Earth's core is, which (hopefully) won't happen for another several billion years.

So it's no wonder that, in March, U.S. Energy Secretary Jennifer Granholm tweeted: "I’m *obsessed* with geothermal, and I’m pumped to see startups launching commercial-scale projects for geothermal — a nearly inexhaustible heat source for clean energy."

So far, however, geothermal provides just a half-percent of the electricity consumed in the U.S., due in part to geographical and geological constraints. And, though it is relatively clean, it has impacts on groundwater and hot springs as well as the people and wildlife that depend on them. We looked into the effort to develop this age-old energy source and how it might help — and hurt — the West.

SOURCES: City of Boise; Boise Warm Springs Water District; Ormat; National Renewable Energy Laboratory; Massachusetts Institute of Technology; Energy Information Administration; Idaho Governor's Office; U.S. Department of Energy; Controlled Thermal Resources; Global Energy Monitor; "Geothermal District Heating in the United States" by National Renewable Energy Laboratory, Amanda Kolker et al.

Illustrations by Hannah Agosta/High Country News

Jonathan Thompson is a contributing editor at High Country News. He is the author of Sagebrush Empire: How a Remote Utah County Became the Battlefront of American Public Lands.

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