Idaho energy plant to use geothermal resource

By Matt Christensen, Times-News writer
Monday, March 19, 2007 5:56 PM CDT

MALTA, Idaho — In the past two years, residents have probably heard a lot about Idaho’s potential for wind power. Same with hydroelectricity, solar technologies and now ethanol.

But perhaps Idaho’s most lucrative green energy source has been under our feet the whole time: geothermal power. It’s relatively inexpensive, plentiful, environmentally friendly to the extreme, and it may just be the key to staving off a potential energy crisis.

Geothermal energy has been linked with the Gem state since Idaho joined the Union in 1890, and even before then when

Indians bathed in geothermal waters. Early settlers used the boiling-hot water to scald hair off of farm animals.

By 1892, Boise was using geothermal heat to warm its buildings. Many homes and public buildings in the City of Trees are still heated by geothermal waters.

But while Idaho has long used the earth’s warmth to heat structures, it’s been slow to adopt the technology for energy production.

Not anymore. The state’s — and the region’s — first geothermal energy plant is under construction at Raft River about 40 miles south of Burley. It’s expected to begin supplying electricity to Idaho Power Co. this fall.

The Raft River project was a U.S. Department of Energy test facility for about two years in the early 1980s, when the federal government became interested in alternative energy production on the heels of the 1970s energy crisis.

The experiment was a success: The site was able to produce electricity from geothermal water using, by today’s standards, archaic technology.

But the project was junked during the Reagan administration after big energy companies found it more lucrative to invest in traditional fossil fuel energy projects. There simply wasn’t enough interest in geothermal power to keep the site running.

The land at Raft River exchanged hands several times before U.S. Geothermal Inc., a Boise-based alternative energy company, bought the land and its water rights in 2001.

The site still looks much like it did in the 1980s —1880s for that matter. The project lies in a valley surrounded by mountains, and from a distance, buildings and water towers are barely visible.

The environmental footprint at Raft River, as well as geothermal sites across the nation, is relatively minor: a handful of pumps that suck hot water from the earth, a building to house turbines and a handful of injection wells to return cooled water to the earth. Above-ground pipes are painted green to match the landscape.

But though the site may be inconspicuous, its impact on Idaho’s energy production won’t be. The first phase of the project could produce about 10 megawatts of power — enough to light about 7,500 homes. U.S. Geothermal hopes to build at least two more phases, each able to produce about 13.5 megawatts of electricity.

In terms of production, that’s still a tiny number compared to the capabilities of Idaho’s hydro plants. For example, Idaho Power Co.’s Milner Dam — just one of 17 hydro facilities run by the utility company — has a 58-megawatt capacity.

Site manager Chris Harriman said U.S. Geothermal’s numbers are based on early test wells, and the project may someday be able to produce 100 megawatts of power.

But that’s a long way down the road. Now, the company and its contractors are drilling test wells, probing 6,000 feet into the earth in search of hot water. The warmer the water, the more productive the project.

It works like this:

Underground water heated by magma is pumped from the ground through wells. It’s transferred by pipe to a building where the water’s heat (approaching 300 degrees at the Raft River site) warms a chemical called isopentane that turns to gas at about 80 degrees. The gas powers turbines that make electricity. The cooled water is then used to cool the gas back to a liquid. The fluid chemical is reused, and the cooled water is returned to the earth via injection wells where magma heats it again.

As long as magma continues to heat the water, it can be used to make electricity.

Geothermal power is more reliable than wind and solar energy, it has virtually no emissions and it has nearly endless potential in Idaho, according to a 2006 report by the Geothermal Energy Association.

That report cited a January 2006 study by the Geothermal Task Force of the Western Governors’ Association that estimated Idaho could produce 850 megawatts of geothermal electricity by 2015 and 1,670 megawatts by 2025. Just 850 megawatts is enough to meet 30 percent of Idaho’s energy needs.

Because of recent federal tax breaks for alternative energy producers — the same tax breaks responsible for a wind-farm boom in Magic Valley — energy companies are rushing to build geothermal plants across the West. According to an Associated Press report in November, 60 new geothermal projects are being considered in Western states.

U.S. Geothermal, the company that owns the Raft River site, is exploring another geothermal project in Oregon.

“It’s just a really exciting time for us,” said company President Dan Kunz, “with a lot of potential. We’re at the forefront of something big.”

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