Sometime this weekend, someone sitting in front of a computer monitor inside a trailer high on the northwest flank of Newberry Crater should see a flicker of light indicating an earthquake happening right beneath their feet.

The earthquake will be cause for celebration, a sign the 30-plus year effort to tap Newberry for geothermal power is moving in the right direction.

Wednesday marked the beginning of what project engineers and geologists call “stimulation,” an attempt to deliberately and carefully crack open the earth by forcing water down a well 10,000 feet deep. Stimulation is scheduled to continue over the next month, ideally opening up interconnected reservoirs of tiny cracks — creating small earthquakes in the process — where 20 million gallons of water can be stored in the superheated rock. Drawn to the surface through a separate well, the boiling water would create steam to spin electricity-generating turbines.

Several test holes have been drilled around Newberry over the years, but none of them has revealed the right combination of heat and water needed for large-scale power generation, said Doug Perry of Davenport Newberry. Davenport Newberry drilled the well at the center of the tests in 2008, but has joined with AltaRock Energy of Seattle to see if optimal geothermal conditions can be artificially created.

As cold water meets the hot rocks below, the rocks will rapidly contract, said AltaRock president Susan Petty. That will break open small fissures in the same way a hot pan tossed in a cold sink is likely to crack. As the fissures open up, the now-heated water will be forced in at 1,300 to 1,900 pounds per square inch, opening the cracks slightly further.

The water for the stimulation process is drawn from a well 600 feet beneath the test site at around 48 degrees, cool enough to induce thermal contraction in the 600-degree rocks below.

“The colder this water is that we can get in the ground, the better this works,” Perry said.

Although nine other sites around the world have produced power by injecting water into artificially created reservoirs, the Newberry project is unique in that it is the first attempt to create a multi- reservoir system, a technique developed by Petty.

At different phases during the next month, the water injected into the well will be blended with a plastic-like substance derived from corn starch. The substance will block off the cracks where they meet the main well, allowing pressure to be applied — and new cracks opened — deeper down the well. If all goes as planned, the process will create three distinct reservoirs that can be refilled with water once the corn starch substance biodegrades. Each reservoir can be tapped for power generation.

Ideally, the 5-acre site could generate as much as 50 megawatts of power, Perry said, enough to power 50,000 homes.

The multiple-reservoirs approach could change the economics of geothermal exploration, Perry said.

“If you’ve got a prime lot, instead of putting a one-story building on it, we want to put a three-story building on it,” he said. “It’s more bang for your buck, because drilling is very expensive.”

Perry added that even if all of the tests produce the results hoped for, an operational power plant at the Newberry site is at least six years away.

A network of 15 seismic sensors encircles the test site, allowing the depth and location of the small quakes generated during stimulation to be pinpointed. Petty expects a web of cracks to open in five to seven days, spanning roughly 1,500 feet from the main well at each of the three levels and creating the three reservoirs.

Further along in the process, two tracer chemicals will be introduced into the well to determine the size of the reservoirs created during stimulation.

Perry said an equal quantity of the two tracer chemicals will be used. One will adhere to the rock and one will not. When water is drawn from the well, a comparison of the concentrations of the two chemicals will indicate how much of the first remains stuck to the rocks underground, and provide an idea of the surface area available where water can meet hot rock.

Petty said any earthquakes generated during stimulation will be too small to be felt, even by the crew at the test site.

Earthquake monitoring

Earthquake monitoring

The Lawrence Berkeley National Laboratory has created a website where the public can monitor earthquakes at the Newberry test site.

http://esd.lbl.gov/research/projects/induced_seismicity/egs/newberry.html

The Lawrence Berkeley National Laboratory has created a website that allows the public to monitor earthquakes at the Newberry test site. Go to http://esd.lbl.gov/research/projects/induced_seismicity/egs/newberry.html