CALIFORNIA TO STORE WIND

PG&E to build plant to store wind energy
Tracy Seipel, August 27, 2009 (San Jose Mercury News)

"Already an aggressive investor in renewable energy projects such as solar power, PG&E…is seeking to build its first-ever facility that would pump compressed air into an underground cavern, using mainly wind energy produced during nonpeak hours, and release it to generate electricity during periods of peak demand.

"The 300-megawatt facility, to be built in Kern County, is projected to cost $356 million and take five years to design and build…[PG&E has] filed for $25 million in federal funding to be used for initial analysis and design costs…"

Compressed Air Energy Storage (CAES) has been long contemplated and pilot projects have been tried but it has never been economically accomplished. (click to enlarge)

"…[T]he facility would use mainly off-peak wind energy to power an air compressor and inject compressed air into the ground, then release it to generate electricity during periods of peak demand…Not everyone is convinced it's the optimum investment.

"The American Wind Energy Association recently released a report on wind power and energy storage that concluded the U.S. was able to add more than 8,500 megawatts of wind power to the grid in 2008 without adding any commercial-scale energy storage…A smart investment for power companies, [the report’s author] said, would be to build more transmission lines and to change the way the power system operates across the U.S. to enable power to flow more easily from region to region…"

Wind professionals say linking wind installations eliminates the need for storage but advocates say CAES has benefits. (click to enlarge)

"…PG&E disagrees…because the utility doesn't believe that so much energy transmission can be built quickly…[T]he state's Independent System Operator, which manages the state's energy grid, supports the Kern County project to help California's grid.

"California requires the state's investor-owned utilities to get 20 percent of their power from renewable sources by 2010. PG&E said it currently has renewable energy contracts that represent more than 20 percent of their customers' future needs."