PNNL

Geothermal technology picking up steam in Washington state

Praveen Thallapally, senior research scientist for Pacific Northwest National Laboratory, talks about experiments to improve methods of removing precious metals from fluids.
Praveen Thallapally, senior research scientist for Pacific Northwest National Laboratory, talks about experiments to improve methods of removing precious metals from fluids. Yakima Herald-Republic

Geothermal heating and cooling isn’t as prominent as other power sources in Washington state.

Near Ellensburg, giant wind turbines can’t be missed. On the Columbia River, huge dams and their spillways make for tourist attractions. Towering transmission lines march across the sagebrush, delivering electricity to the region.

Against this backdrop, geothermal energy — essentially hot water drawn from within the Earth for both heating and cooling — may seem like a bit player.

But work is continuing in Washington state to improve scientists’ understanding of how heat rises from inside the Earth, increasing chances that geothermal energy could become a mainstream commercial source.

And Gov. Jay Inslee this year approved a bill to smooth the process for experimental drilling in search of the right areas for geothermal wells.

Sen. Sharon Brown, the Kennewick Republican who sponsored the bill, said she believes the legislation is part of the answer to increasing geothermal use in the state.

“The more we can move that forward, it’s really going to help the state as a whole,” Brown said.

Geothermal energy is attractive because it is a renewable natural resource, like water or wind.

“I believe this can play a meaningful place in that portfolio,” Brown said.

Geothermal energy comes in two main types: major power production similar to more well-known generation systems such as hydroelectric or wind turbines, and heating and cooling systems for everything from homes to commercial complexes.

The technology stretches back to historic times. The conversation around geothermal research picked up steam in the 1970s, though cheaper energy through other sources drew attention away.

Washington has been slow to develop geothermal as a larger portion of its energy portfolio, in part because of complex geology that hinders reaching the hottest areas.

Utah and Nevada, for example, have working geothermal power plants because it’s easier to reach key sources. Unlike more open, arid sections in those and other Western states, Washington’s largest likely geothermal areas tend to be covered by trees and see significant rainfall, according to the state Department of Natural Resources. Access also is complicated by high elevations and rugged slopes, the agency said.

At the research level, however, state and federal officials are pushing forward to answer questions about how best to access geothermal sources.

DNR is continuing efforts to map the three areas of the state identified as having the highest potential for geothermal value. They are all in the Cascade range: the Mount St. Helens seismic zone, the southeast flank of Mount Baker and the Wind River valley in the Columbia Gorge.

Yakima County and large portions of the Columbia Basin provide lower-heat options that are more suitable to localized development, such as for homes and businesses.

A recent Benton County residential development was built with a geothermal heating and cooling grid.

A recent Benton County residential development, for example, was built with a geothermal heating and cooling grid. That’s a closed-loop system, which uses buried pipes to cycle water through the ground to heat and cool the structure as needed.

About 70 open-loop geothermal heating systems are active in Yakima County, meaning those that draw from an open well. They include everything from the Yakima County jail, which started using the geothermal system in the 1980s, to orchards and churches.

Jim Kohl, a retired Gleed fire chief, recalled that a geothermal heating and cooling system was installed when the fire department’s new headquarters station was built about 20 years ago. The design team for the building suggested such a system because it reduces spending on electricity or other sources for heating and cooling, Kohl said.

“I think it has definitely saved the district some money,” Kohl said.

Chuck Murray, a senior energy policy analyst for the state Department of Commerce, said geothermal temperature control can make sense for larger buildings, such as a recent project on the Capitol campus in Olympia that was able to meet environmental standards partly by relying on a geothermal system.

We are a power-hungry world, and particularly a nation. I think it’s an absolute necessity as part of the power production mix.

Chris Brown, PNNL

Whether for residential or larger construction, initial expense will generally translate to savings down the road.

The U.S. Department of Energy says geothermal heat pumps can use as much as 50 percent less energy than conventional heating or cooling systems.

“It’s a mature technology, it has low operating cost — it just costs more up front, but you have to take the long view,” Murray said.

Some of the most robust research in the region regarding geothermal viability is being done at the Pacific Northwest National Laboratory in Richland. A mix of scientists there are studying a range of related technologies.

One project is focusing on how to extract rare earth minerals from the water that is cycled through a deep-bore geothermal system. As the water makes its way through rock, it picks up the minerals, which could then be extracted for sale or use in other technologies, such as solar panels.

One reason for the research is creating a domestic source for rare earth minerals in order to reduce reliance on the international market. China is the primary provider of rare earth right now, PNNL representatives said.

PNNL scientists also are modeling and testing ways to break up rock to allow water to better reach areas where it can be heated underground.

Their focus is reducing the number of chemicals used in current rock-breaking, or fracking, procedures in commercial oil exploration.

Chris Brown, a PNNL research team leader whose work includes geothermal science and development, said the region has potential for expanding geothermal options. The more that can be done to reduce carbon dioxide emissions through renewable sources such as geothermal, the better, he said.

“We are a power-hungry world, and particularly a nation. I think it’s an absolute necessity as part of the power production mix,” he said.

How geothermal works

Deep in the Earth, rocks send off heat.

Water picks up that heat — sometimes more than 300 degrees — and circles through the aquifer, rising toward the surface.

Drill down deep enough — thousands of feet, in some cases — and that hot water can be brought to the surface to heat and cool everything from homes to large buildings. At large enough volumes, the same hot water can generate electricity, just like a hydroelectric dam or nuclear plant.

In Washington, the hottest areas are close to the volcanic areas of the Cascades. Less is understood about the heat source for the Columbia Basin, which tends to have lower-temperature water.

The U.S. Department of Energy says about 50,000 heat exchange systems are installed each year across the country.

While installation costs are higher than for standard air-exchange systems, that expense can be returned in savings over five to 10 years, according to DOE.

  Comments