A 500 MW pumped energy storage project jointly proposed by the City of San Diego and the San Diego County Water Authority has received $18 million in the California state budget. The support will help finance the San Vicente Energy Storage Facility through initial design, environmental reviews and the federal permitting process.
The project would provide long-lasting stored energy and is seen by lenders as an asset that will help avoid power outages through on-demand power generation. It could also generate revenue to help offset the cost of purchasing, storing and treating water.
With state funding, the Water Authority and the city now plan to initiate federal and state environmental assessments, seek a project license from the Federal Energy Regulatory Commission, and issue a request for proposals for a partner to assist. to develop the project. These stages are expected to take at least four years, with construction completion expected in 2030.
As planned, the San Vicente project would create a small upper reservoir above the existing San Vicente reservoir, as well as a tunnel system and underground power plant to connect the two reservoirs. The plant would contain four reversible pump-turbines. The project could store 4,000 MWh of energy per day (500 MW of capacity for eight hours).
During off-peak times, the turbines would pump water to the upper reservoir where it would act as a battery of stored potential energy. During high power consumption, the system evacuated water from the upper reservoir to the bottom through the turbines, producing power. The exchange between the two tanks would not consume water.
The San Vicente Reservoir is northeast of San Diego near major transmission facilities, which would allow it to play a role in integrating power from across the southwest for use in the San Diego County. The San Vicente project would be a closed loop system containing mostly imported water and would not be dependent on runoff which can fluctuate from year to year.