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Unalaska takes the next step
The City of Unalaska is now looking at a pre-feasibility stage for its concept of a geothermal power plant at the side of the Makushin Volcano, City Manager Chris Hladick told Petroleum News on June 6. The city has conducted talks about how to progress the project with Richmond, Calif., based Geothermex, a company that specializes in geothermal exploration and development, Hladick said. Geothermex would provide engineering and geology services and oversee any drilling, if the project proceeds.
“We’re putting together a conceptual design,” Hladick said.
Discovered in 1982 The U.S. Department of Energy discovered a 390-degree-Fahrenheit geothermal water source on the flank of Makushin Volcano in 1982. Since then several ideas for harnessing the geothermal energy have come to nothing, after foundering on the challenging economics of geothermal development in a remote and isolated community. But advances in the technology for binary cycle geothermal power generation have led to renewed interest in the Unalaska geothermal site. In 2005 Iceland America Energy, a subsidiary of Enex Corp., acquired geothermal rights on the slopes of the volcano and proposed a 50-megawatt power station, coupled with a heat exchanger that would enable hot fresh water to be pumped to town to heat buildings.
However, Unalaska now wants to investigate the potential for developing a geothermal facility in the valley floor next to the volcano, rather than on the higher ground on the volcano itself — DOE discovered the original geothermal source from a bench feature at an elevation of 1,200 feet. Access to the bench involves negotiating a “hellacious switchback road,” while the bench is subject to relatively high snowfall and suffers from unstable soil conditions, Hladick said.
By contrast the valley floor is at an elevation of 400 feet. And construction of a road from town to the valley floor site would be much simpler and involve a shorter route than building a road to the bench, Hladick said.
The plan now is to drill some 2.5-inch, slim-hole wells to a 1,000-foot depth in the valley floor, to test for a geothermal source. That investigation will enable a decision on whether the power plant should be located in the valley floor or at the original bench site. Once the site is determined, it will be possible to make the cost estimates necessary to carry out a feasibility study for the project. “I think we’re looking at $3 million to do the slim-hole work,” Hladick said.
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