EVERETT — If geothermal power eventually flows into homes in Snohomish County, it likely won’t be coming from the nearby Cascade Mountains.
The Snohomish County Public Utility District’s drilling effort in the mountains near Index hit bedrock and had to be scrapped, officials said. The site was considered the best possibility in the area, based on earlier test drilling. Now the utility will turn its attention elsewhere in the state.
“It doesn’t appear we can find a place in Snohomish County,” PUD general manager Steve Klein said.
Geothermal power is created when steam, heat or hot water from underground reservoirs is used to spin turbine generators. The water is heated by magma farther below.
The PUD has estimated that geothermal energy could power up to 37,500 homes in Snohomish County and Camano Island, spokesman Neil Neroutsos said.
The PUD is working with consultants to study other parts of the Cascades that might pan out for geothermal power, said Craig Collar, PUD manager for energy resource development. The utility also plans to make use of information being collected by the state Department of Natural Resources, which is doing its own study.
This will include test drilling in the Cascades in the fall, said Dave Norman, the head geologist for the state.
Two areas look promising, based on preliminary information, Norman said.
One is the area between Mount St. Helens and the Columbia River. “Mount Baker has some potential as well,” he said.
Officials with the PUD hope that if a site is located, it’s near transmission lines. The cost of getting the energy to Snohomish County will be a factor, Klein said. The PUD had high hopes for the local site, near the Garland Mineral Springs northeast of Index, because it was so close to the utility’s transmission lines.
It fit with the PUD’s recent strategy of “look in our own back yard first and move out from there only when necessary,” Collar said.
The utility hopes to diversify its energy portfolio. It currently gets about 92 percent of its power in the form of hydroelectric energy from the Bonneville Power Administration.
The PUD recently built a $29 million mini-dam on Youngs Creek near Sultan and is studying building a small dam at Sunset Falls on the Skykomish River near Index. The possibility of a dam in that location is opposed by environmental groups and some nearby residents.
The PUD spent about $3.6 million on the Garland well and another $300,000 on earlier test wells, but received a $475,000 federal grant for the work, Neroutsos said. Altogether it’s spent about $3.4 million on the endeavor.
The PUD in 2010 first drilled several 700-foot test wells in the mountains near Index looking for high ground temperature. One stood out as promising and, last fall, crews began drilling a mile deep in search of hot water.
Geothermal power needs loose, permeable rock and soil to work, Collar said. In the Garland well, crews hit solid bedrock not far below the 700-foot test level and it just continued from there. After reviewing the data from the well, PUD officials decided during the spring to give up on the site.
It’s also nearly surrounded by the federally protected Wild Sky Wilderness, so moving a mile or two over was not an option, officials said.
“We would have had to hit it perfectly,” Klein said.
Development, even the low-impact type represented by a small geothermal plant, is tightly restricted in wilderness areas. If the PUD had asked for a special permit, it would potentially have opened the door for other utilities or developers to do the same, and would undoubtedly have met lot of resistance, Klein said.
Geothermal power is a good, consistent energy source once it’s found, he said. Geothermal plants are operating elsewhere in the nation, including California, Idaho and Nevada. If the PUD is able to develop geothermal power, it would be the first utility in the state to do so.
Norman said Washington state has good geothermal potential, though its drawbacks include “complicated geography and high rainfall.”
The state will share the results of its test drilling with interested utilities, including the PUD, Norman said. The state is not getting into the geothermal power business, he said.
The information, he said, “will allow people to do better exploration for geothermal energy in the state.”
Bill Sheets: 425-339-3439; firstname.lastname@example.org.