In Utah, company aims to store
energy in air
Feb 7, 2010 - Paul Foy - The Associated
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
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,
"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."
A futuristic type of energy storage
could involve putting the battery capacity of plug-in
electric vehicles to work for the electric grid.
It could take extra power from vehicles when needed,
while ensuring a vehicle is properly charged overnight,
said Daniel Laird, a researcher for Sandia's wind
energy technology group.
That will work only when plug-in cars
make up a big part of the U.S. vehicle fleet, however.
For now, "we've got to find a way
to store renewable energy for when people need it,"
said Steve Michel, a former utility executive who
works for Western Resources Advocates, a Boulder,
Colo.-based nonprofit law firm.
Other forms of energy storage involve
lumbering flywheels or banks of batteries, but they
have limited capacities and can be costly.
"In terms of storing bulk energy -
lots of megawatt-hours - compressed air is cheaper
than anything else out there," said Paul Denholm,
lead analyst for energy storage at the U.S. Department
of Energy's National Renewable Energy Lab in Boulder,
In Utah, Magnum snapped up rights
to the largest known salt deposit in the American
West, a bed one mile thick by several miles wide.
It has the advantage of being close to several energy
producers; another company is planning a major solar
farm in Utah's west desert.
"The physical location of that salt
deposit is just tremendously valuable, said Scott
Jones, managing director of Houston-based Haddington
Energy Partners III, which is backing the project.
"It's the only one everybody knows about or has
been found. We're excited about it."
Each impermeable cavern will hold
the volume of an Empire State Building, said Craig
Broussard, another Magnum partner.
That's billions of cubic feet of storage
capacity of natural gas, liquid petroleum or compressed
The company would take excess energy
from wind or solar farms or other energy producers,
use it to pump compressed air underground and let
it out to generate power during peak-use times.
The system would lose some energy
to pumping, and the released air would need to be
mixed with some natural gas to power air expansion
turbines. Still, "this is far more efficient than
a conventional power plant," Broussard said.
"The power industry is like being
in an ice-cream business without a refrigerated
warehouse," he said. "This kind of storage provides
a warehouse of energy."
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