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Researchers to store energy under volcanic ground

US project could see volcanic rock act as battery to store energy generated from wind and thermal power

Researchers aim to see if energy can be stored under volcanic ground
Researchers aim to see if energy can be stored under volcanic ground

US researchers have started a project to look at whether volcanic ground could serve as a good terrain for storing renewable power. The researchers are studying whether the volcanic ground beneath the Columbia Basin, the drainage part of the US’s Columbia River, could serve as a kind of subterranean battery by storing abundant renewable energy for later use.

The Department of Energy's Pacific Northwest National Laboratory and US energy firm, the Bonneville Power Administration (BPA) are sponsoring the joint research project.

The study focuses on storing energy within the Columbia River Basalt Group, which underlies many wind and thermal power generators in the region. It's the predominant geologic formation in the Pacific Northwest east of the Cascade Mountain Range.

Energy storage could help the Northwest power system integrate intermittent wind power by adding more flexibility to absorb extra energy when generation exceeds demand and delivering it back to the grid when it is needed.

In this case, BPA could store energy deep in the porous layers between individual basalt flows when there's excess electricity generation available and then retrieve it later.

The method displaces the water naturally retained in the porous basalt with injected air, heated water or CO2. The displaced water then helps maintain discharge pressures in the extraction phase.

This is an important part of the process because the water pushing on the air as the air is withdrawn prevents air leakage and pressure loss, which results in wasted energy. It's the efficient combination of naturally occurring storage formations, high ambient pressures deep within the basalt, and the storage characteristics of thermal energy and compressed air that makes this an appealing storage solution.

Steve Knudsen, BPA project manager, said: “Cost-effective large-scale energy storage could transform the regional electric industry. And although the technology and low costs of rapid cycling of compressed air storage in basalt is unproven, there's enough potential there to invest in this research. And at a minimum this project will help us focus future research into the best ways to integrate large amounts of variable energy supplies into the regional power system."

The project focuses on identifying individual geologic structures capable of storing up to 110,000MW hours of power.

BPA is funding about half of the approximately USD 800,000 research study. The project is also being supported by Washington State University, Dresser-Rand, GreenFire Energy, Magnum Energy, Northwest Natural, Portland General Electric, Puget Sound Energy, Ramgen Power Systems, Seattle City Light and Snohomish County Public Utility District.