The Clean Power Alliance on June 28 approved a 10-year contract for generation from the 12-MW Isabella hydroelectric project in Kern County, beginning in December 2020.
CPA documents say the output is summer peaking and amounts to about 48,000 MWh per year.
The facility, which is eligible under California’s renewable portfolio standard, is currently under contract with Southern California Edison through mid-December 2020.
The Isabella hydro project generates power as a run-of-river operation using water impounded in Lake Isabella by its main and auxiliary dams in the Kern Valley, with releases controlled by the U.S. Army Corps of Engineers for flood control and for irrigation in the Bakersfield area.
The project, owned by Central Hydroelectric Corp., is located at the base of the main dam. It generates power as long as the lake elevation is above about 2,537 feet. The turbines are taken off line below this level because the low head available drops below the turbine design criteria.
The dams are currently undergoing safety upgrades slated for completion in 2022 that will address overtopping, as well as seismic and seepage issues.
The upgrade work includes 16-foot raises and improvements to both the main and auxiliary dams; improvements to the existing service spillway; and construction of a new 1,500-foot-long, 300-foot-wide, and 100-foot-deep emergency spillway.
The Corps reported “no damages or operational impacts” to the Isabella dams in the aftermath of the magnitude 6.4 and 7.1 earthquakes on July 4 and 5, respectively. They are located about 50 miles west-southwest of the epicenters.
CPA is a community choice aggregator serving 3 million customers as a coalition of 31 agencies in Los Angeles and Ventura counties. The power it purchases is delivered by Southern California Edison.