Pacific Gas & Electric Asks for $25 Million for Compressed Air Energy Storage

Pacific Gas & Electric (PGE) wants $25 million from the Department of Energy's Smart Grid demonstration grant program to build an underground compressed air energy storage facility. The utility plans to use the compressed air during peak demand times to generate inexpensive electricity. The $25 million would be used to design the facility. Total project cost is estimated to be more than $300 million, and it could take five years to get it online.

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The facility would take wind power generated at night to pump compressed air into a porous rock formation, and generate electricity as needed during the day by forcing the air into a turbine. Typically, California winds blow strongest at night, then drop off significantly during the day. The plant would be able to generate 300MW for periods of up to 10 hours. A utility spokesman said the "right geology" is needed to make such a storage project work, but added that the required formations aren't rare and can be found around the country.

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The PG&E proposal is one of a handful of demonstration project applications that have been publicly announced. The first was from Southern California Edison. The utility also wants $25 million, but SoCal Edison wants to set up a 32MW-hour lithium-ion battery to allow it to add more wind energy to its system. And, Oncor has asked for $3.5 million to design tension monitoring equipment that would provide real-time analyses of transmission line capacity. The application deadline for demonstration grant money was Aug. 26.

   Quick Take: Interesting juxtaposition here, and it will be interesting to see the outcomes of these applications. According to the Electric Power Research Institute, compressed air energy storage is one of the cheapest ways to generate electricity. But staggering costs have hampered development of grid-scale storage batteries, although supporters have long contended that costs could drop as more go online.

   San Francisco Chronicle article

   SGN Oncor profile

   SGN PG&E profile

   SGN SoCal Edison profile