Geothermal under the Cascades

Mt. St. Helens courtesy of Wikimedia

By Les Blumenthal
McClatchy Newspapers
Jan. 24, 2008

Deep beneath the Cascades Mountains, where molten magma heats the Earth's crust and occasionally bursts through cracks and fractures in violent volcanic eruptions, lurks an energy source that scientists think could be tamed to help power the Northwest.

Though there's been little exploration, and no deep test holes have been drilled, the geothermal potential of the Cascades — which run from Washington state south through Oregon into Northern California — is starting to attract a buzz. In the next 10 or 15 years, some say, commercial-sized power plants could start generating electricity.

"As this area is predicted to contain vast geothermal resources, development plans for the Cascades are becoming an increasingly frequent topic of conversation," said a report late last year for the Department of Energy.

Behind Iceland, which gets more than 26 percent of its electricity from geothermal plants, the United States is a world leader in geothermal development, with plants pro
ducing more than 3,000 megawatts of electricity.

California is No. 1, and resources in such other Western states as Nevada, Utah, Idaho and Oregon are being developed. Nevada has been dubbed the "Saudi Arabia of geothermal."

A recent Massachusetts Institute of Technology study found that the amount of geothermal power that could be recovered from deep drilling would represent almost 3,000 times the amount of energy currently consumed in the United States.

Last year's Energy Department report said the Cascades contained "potentially significant" geothermal resources, but it cautioned that the effort to tap these resources — including drilling miles into volcanoes to tap "supercritical fluids" — won't be easy.

Even so, the hunt is under way, and some energy companies have zeroed in on certain areas.

Near Baker Lake, north of Seattle, an Oregon company is waiting for leases from the Forest Service and considering a 100-megawatt geothermal plant that could provide enough electricity for 100,000 people. The power it would produce would be cheaper than the electricity from a new natural gas-fired generating plant.

"We are very serious about this," said Steven Munson, the chief executive of Vulcan Power Co.

In the rough triangle from Mount St. Helens and Mount Adams in Washington state to Mount Hood, east of Portland, there's enough geothermal potential to develop 1,000 megawatts of electricity, the equivalent of three or four gas-fired generating plants, said Susan Petty, president of AltaRock Energy in Seattle.

The Cascades are part of the so-called "Ring of Fire" of active volcanoes and earthquake faults that surround the Pacific Ocean.

Southeastern Washington, eastern Oregon, southern Idaho, eastern California, Utah and Nevada are in a zone marked by deep fractures in the Earth's crust that tend to be pathways to the deep circulation of hot water.

Though that water is hot enough to run steam turbines, Petty and others said the temperatures of the geothermal water and hot rocks underlying the Cascades might be even better for producing power. And because magma is closer to the surface in the Cascades, the drilling holes there might not have to be as deep.