The California Energy Commission recently approved a permit for Rice Solar Energy, LLC, a subsidiary of SolarReserve, LLC, to build a 150-MW molten salt solar energy storage facility, which will be located 30 miles from Blythe, California. The project has a 25-year power purchase agreement with Pacific Gas & Electric (PG&E). The project was approved on December 15, 2010, and would be California's first molten salt solar storage facility.
Molten salt solar storage technology works by reflecting sunlight from a group of tracking mirrors (heliostats) to a receiver located on top of a central tower. The heliostats are focused on the receiver as they track the sun during the day. The receiver collects the concentrated sunlight and uses it to heat molten salt (a mixture of sodium and potassium nitrate) to more than 1,000 degrees Fahrenheit. The molten salt then goes into a thermal storage tank, where it can be sent to conventional steam turbines for power generation. The molten salt is then returned to a thermal storage tank to repeat this cycle.
According to SolarReserve, the project still must receive approvals from both the California Bureau of Land Management and the Western Area Power Administration. If approved, construction would begin in the first quarter of 2011, startup testing in the first quarter of 2013. Commercial operation is expected to begin by the third quarter of 2013.
Molten salt solar storage is emerging as an interesting component of the energy storage picture. Earlier this month, SolarReserve received approval from the U.S. Department of the Interior for a 100-MW molten salt solar storage facility in Nevada, the Crescent Dunes Solar Energy Project, and environmental permits from the state of Arizona for a proposed 150-MW molten salt solar storage power plant 70 miles southwest of Phoenix.