NJ Startup Using Compressed Air to Store Green Energy

Philly.com is reporting that central New Jersey venture, Energy Storage and Power LLC, is using technology common in the oil and gas industry to store electricity in compressed air inside large underground caverns, abandoned mines, and other spaces. The air is then released at key times to produce energy.

Mass energy-storage systems will become increasingly critical as the nation's energy markets shift to comply with laws favoring renewable power over greenhouse-gas-emitting fossil fuels. Among several alternatives - ice-storage systems, pumped-storage hydroelectric plants, massive battery arrays - the compressed-air systems are considered the most cost-effective.

If renewable power is to constitute 20 percent of the nation's electrical supply - about 9 percent now comes from renewables, mostly hydroelectric - the nation will need 114,000 megawatts of electrical-storage capacity, according to a study published last year by the American Institute of Chemical Engineers.

"That's about a $342 billion market," Byrd said.

Though compressed-air storage sounds exotic, the process employs technology and equipment already extensively used by oil and gas developers to force hydrocarbons to the surface by pumping high-pressure gas and liquids underground.

And Byrd said storing compressed air in depleted salt mines or gas fields was no different than the technique utilities use to store high-pressure natural gas underground ahead of the heating season.

"We're just storing air. We're not storing hydrocarbons," he said. "So it's much more straightforward."

As the compressed air is released and expands, it becomes very cold and must be mixed with natural gas to drive a conventional turbine generator. The mixture saves about 65 percent of the gas used by a fossil-fuel turbine.