If approved, the project would include an advanced thermal-storage system using molten salt to store electricity for later use, PG&E said. The project could be operating as soon as October 2013, PG&E wrote, in a document filed with the California Public Utilities Commission. The company asked the CPUC to approve the contract by July 2010.
Under pressure to use increasing amounts of renewable power, PG&E has been on the hunt for promising storage technology that can capture electrons produced by solar generators during the day or wind turbines at night for use at other times.
Solar Reserve’s Rice solar project will use thousands of mobile mirrors to focus sunlight onto a receiver in a central tower to heat 4 million gallons of molten salt to more than 1,000 degrees Fahrenheit, PG&E said. The hot, liquid salt will heat water for a steam generator to produce electricity. The stored molten salt can also provide energy at night or during cloudy days when sunlight is dim, PG&E said.
The price PG&E has agreed to pay is confidential, but the utility said it would be above the benchmark renewable-energy price set by the CPUC each year, which would be more than 11.2 cents a kilowatt-hour, the agency’s proposed benchmark renewable-energy price for projects contracted in 2009, with energy deliveries starting in 2013.
PG&E and other California utilities are required to use renewable sources for a fifth of the power they sell by the end of 2010, with the mandate expanding to one-third renewables by 2020. The requirements are part of California’s 2006 plan to combat climate change.