Geologists believe Newberry Volcano was once one of the tallest peaks in the Cascades, reaching an elevation of 10,000 feet and a diameter of 20 miles. It blew its top before the last Ice Age, leaving a caldera studded with towering lava flows, two lakes, and 400 cinder cones, some 400 feet tall.
Although the volcano has not erupted in 1,300 years, hot rocks close to the surface drew exploratory wells in the 1980s.
Over 21 days, AltaRock will pour 800 gallons of water per minute into the 10,600-foot test well, already drilled, for a total of 24 million gallons. According to plan, the cold water cracks the rock. The tiny plastic particles pumped down the well seal off the cracks. Then more cold water goes in, bypassing the first tier, and cracking the rock deeper in the well. That tier is sealed off, and cold water cracks a third section. Later, the plastic melts away.
Seismic sensors produce detailed maps of the fracturing, expected to produce a reservoir of cracks starting about 6,000 feet below the surface, and extending to 11,000 feet. It would be about 3,300 feet in diameter.
The U.S. Bureau of Land Management released an environmental assessment of the Newberry project last month that does not foresee any problems that would stop it. The agency is taking public comments before making a final decision in coming months.
No power plant is proposed, but one could be operating in about 10 years, said Doug Perry, president and CEO of Davenport Newberry.
EGS is attractive because it vastly expands the potential for geothermal power, which, unlike wind and solar, produces power around the clock in any weather.
Natural geothermal resources account for about 0.3 percent of U.S. electricity production, but a 2007 Massachusetts Institute of Technology report projected EGS could bump that to 10 percent within 50 years, at prices competitive with fossil-fuels.
Few people expect that kind of timetable now. Electricity prices have fallen sharply because of low natural gas prices and weak demand brought about by the Great Recession and state efficiency programs.
But the resource is vast. A 2008 USGS assessment found EGS throughout the West, where hot rocks are closer to the surface than in the East, has the potential to produce half the country’s electricity.
“The important question we need to answer now,” said Williams, the USGS geophysicist who compiled the assessment, “is how geothermal fits into the renewable energy picture, and how EGS fits. How much it is going to cost, and how much is available.”<< previous 1 2 3 4