In Utah, Magnum Gas Storage aims to store energy in air

SALT LAKE CITY — A Utah company plans to dig a series of underground caverns that it hopes to one day fill with compressed air, releasing it to generate electricity by turning a turbine and solving one of the most vexing problems facing the clean-energy industry — how to store power.

Under a barren patch of Utah desert, a private-equity group is bankrolling the project to hollow out a series of energy-storage vaults from a massive salt deposit a mile underground. It promises to make a perfect repository for storing energy and, in effect, creating a giant subterranean battery.

Energy storage is catching on as a way to make wind and solar power more useful.

Without energy storage, the output of solar and wind power is so erratic — the wind doesn't always blow; cloud cover can shut down solar cells — that utilities can take only so much of it, said Jim Ferland, senior vice president for operations for PNM Resources, the New Mexico utility.

If renewable power makes up too big a part of a utility's energy mix, it can make the delicate act of balancing loads on a power grid difficult. The lack of storage is one of the things holding back clean energy, say scientists for Sandia National Laboratories' energy systems group in Albuquerque, N.M.

"Storage is the key here," said Charlie Hanley, manager of Sandia's photovoltaic and grid integration group. "We have to find a way to overcome intermittent swings from cloud cover."

The only commercial-scale, compressed air power plants are in McIntosh, Ala., and Bremen, Germany. Other projects are under development in Norton, Ohio, and Ankeny, Iowa.

Initially, because of market needs, Salt Lake City-based Magnum Energy LLC will store natural gas for Rocky Mountain producers, taking it from a nearby interstate pipeline, in an "energy hub" near Delta, Utah. It hopes to start dissolving the first cavern within a year.

Later, the company is looking to dig other caverns at the site for compressed air, which could store excess energy generated by a nearby wind farm and then release it later when demand is high to turn turbines and create electricity, and possibly for carbon storage, which could trap a neighboring coal-fired power plant's emissions.

Still other caverns could be devoted to liquid petroleum; yet another pipeline for liquid fuels, passing through the same part of Utah, is close to receiving federal approval.

The company filed for federal approval in December to build its versatile "energy hub."