Ormat says Spurr geothermal project still in the works

Alan Bailey

It has been a year or two since much has been heard about Ormat Technologies' project to explore for geothermal resources on the flanks of Alaska's Mount Spurr, the active volcano about 80 miles west of the city of Anchorage. But the project is continuing to progress, Alison Payne, a consultant working for Ormat on the project, assured the Alaska Rural Energy Conference on April 29.

"This project is still alive and well," Payne said. "We're in a bit of a hiatus, looking into options for a power plant to be built in the future. We're planning on drilling again in 2014."

Ormat anticipates doing some fieldwork this year, locating well sites for that next phase of drilling, she said.

With the volcano just 40 miles west of a natural gas-fired power station at Beluga on the west side of Cook Inlet, Ormat's concept has been to build a utility-scale geothermal power plant, using heat from the volcano, and to connect that power plant via a new transmission line to Beluga. The Beluga power station is connected into the Alaska Railbelt electricity grid.

To pursue the project, Ormat needs a geothermal resource that can generate 50 megawatts of power, Payne said. The concept is to find a sustainable source of hot subsurface geothermal water that can boil a relatively low boiling point fluid, with vapor from that fluid driving a turbine generator before being recycled through the system.

Ormat has leased 36,000 acres of state land on the southern flanks of Mount Spurr and began exploration of its acreage in 2009 by conducting various forms of aerial survey, coupled with gravity and electro-magnetic measurements, seeking evidence of hot water and suitable geologic structures that might justify focused exploration of specific prospects.

In 2010, the company drilled two core holes to depths of 1,000 feet. And, with those core holes having shown promising indications of a suitable geothermal resource, in 2011 the company brought in a rig to drill to a depth of 4,000 feet.

But the results from that deeper well proved somewhat disappointing. Although the well provided valuable information about the subsurface geology, it did not find hot water, and the highest subsurface temperature encountered was only 140 degrees F, Payne said.

For this initial drilling, Ormat chose a site toward the eastern side of its leased acreage, at a location where hazards from the volcano are relatively low and where the distance to Beluga is at a minimum, Payne said.

But, having discounted the geothermal potential of this area, the company now plans to drill farther to the west, closer to the volcano's active crater, where subsurface temperatures are likely higher but where the dangers posed by a volcanic eruption are also elevated, she said.

And, in parallel with planning the drilling, the company is evaluating the engineering of a suitably protected power plant.

"It's definitely doable," Payne said. It's essentially a question of looking at the risks and figuring out the risk mitigation costs, she said. And if a power plant does turn out to be feasible, it could be built in about five years, potentially providing near-term help in tackling Southcentral Alaska's energy challenges, she said.

In 2012 Ormat said that it had spent about $3 million on its Mount Spurr project, in addition to the $3.5 million it had paid for the state geothermal leases. The state has also been providing some funding for the project.

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