WASHINGTON — Deep beneath the Cascades Mountains in the Northwest, 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 region.
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 predict, 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 producing 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 areas that they think could be developed.
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. Steven Munson, the chief executive of Vulcan Power Co., said there was more than an 80 percent chance that the plant would be built. It would be designed to blend into the landscape, and the power it would produce would be cheaper than the electricity from a new natural gas-fired generating plant, Munson said.
"We are very serious about this," he said.
On the east slopes of the Cascades, in Yakima and Kittitas counties south of Seattle, a Utah firm, Raser Technologies Inc., is focusing on 5,000 acres of International Paper Co. land for possible development.
"There is a lot of geothermal in Washington state," said Richard Putnam, a Raser executive. "It's already happening. It's a matter of how much and when."
In the rough triangle from Mount St. Helens and Mount Adams in southern Washington state to Mount Hood, east of Portland, Ore., there's enough geothermal potential to develop 1,000 megawatts of electricity, the equivalent of three or four gas-fired generating plants or a large nuclear plant, said Susan Petty, the president of AltaRock Energy in Seattle and a geologist.
The Cascades are part of the so-called "Ring of Fire" of active volcanoes and earthquake faults that surround the Pacific Ocean. Geothermal development also is under way in such countries as Japan and Indonesia.
Southeastern Washington, eastern Oregon, southern Idaho, eastern California, Utah and Nevada are in a zone — known as the Basin and Range — where the North American continent tried to pull apart 30 million years ago. The area is 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.
Hot springs and other surface indications of geothermal activity are easier to spot in arid areas. In the Cascades, the "rain curtain" and runoff from melting snow make it harder to pinpoint potential geothermal areas.
"The Cascades have always been an area of interest, but it is so wet the heat flow is masked," said John Lund, the director of the Oregon Institute of Technology's Geo-Heat Center in Klamath Falls.
Some potential hot zones underneath the Cascades might contain hot water that could be pumped to the surface and used to produce electricity. In others, water might have to be injected into dry hot rocks, then pumped back to the surface.
One reason for the growing interest in geothermal in the Cascades is a requirement that 15 percent of the energy that Washington state's major utilities use come from renewable sources by 2020. California and Oregon have similar requirements.
Democrats failed in their effort to include a federal renewable requirement in the energy bill that Congress approved last year. But Sen. Jeff Bingaman, D-N.M., has introduced legislation that would set a national goal that 20 percent of electrical production in the United States come from geothermal resources by 2030. The bill also would authorize spending nearly $500 million over the next five years on geothermal development.