Wednesday, April 25, 2001
Californians, pay attention. An inactive limestone mine in
northeastern Ohio may be an answer to the energy crisis.
Researchers at the Department of Energy's Sandia National
Laboratories are exploring the possibility of using the mine as a compressed-air
energy storage vessel. "What exists now is a very large space underground, about
2,200 feet," explains Steve Bauer, principal member of Sandia's technical staff.
"They'll plug off access ways to the mine, and then access the mine with
specially designed air tubes." The turbines then heat the air to super-expand
it, helping the system run more efficiently.
Low-cost energy compresses air underground in an inactive mine,
where it is stored and generated later when needed during peak demand.
Drawing from Sandia Lab, not drawn to scale.
Because some natural gas is burned as the air super-expands, the
entire system-running at full capacity of 2,700 mw-is more environmentally
friendly than a 600-mw power plant that creates the same amount of
"The plan is to run compressors during off-peak hours [nights and
weekends] and use the less-expensive energy to force the air underground," says
The mine suits energy storage applications due to its large
volume, low permeability, and depth. According to Bauer, "The deeper it is, the
greater the Earth's pressure, and the greater the air pressure." However, too
much air pressure could cause fractures in the rocks of the mine.
Don't expect these mines to pop up across the country, rendering
the energy crisis nonexistent. Regarding Sandia's choice of the inactive Ohio
limestone mine, Bauer sums it up, "The space was there."