The Water Authority and the City of San Diego are jointly exploring the development of an energy storage facility near San Vicente Reservoir to leverage existing water and energy infrastructure and reduce upward pressure on water rates while expanding renewable energy potential across the region.
The benefits of energy storage include:
The agencies are co-permittees on a preliminary permit issued by the Federal Energy Regulatory Commission, an early step in the process of determining if and how the project could be operational by 2025.
The Water Authority and the City of San Diego also are negotiating with Tenaska Inc.-Diamond Generating Corp. Joint Venture to draft a Project Development Agreement for consideration by each agency’s governing board in spring 2018. Tenaska-Diamond was the top choice among five groups of companies vying to develop the San Vicente energy storage project based on its financial modeling, risk analysis, knowledge of the energy market, and revenue-sharing proposal. The agencies may begin negotiating with Brookfield US Generation LLC in the event talks are unsuccessful with Tenaska-Diamond.
The negotiations do not commit the Water Authority or the City of San Diego to developing the project, which would require an environmental review and additional approvals by the Water Authority’s Board and the San Diego City Council.
The project under consideration by the Water Authority and the City of San Diego would establish a smaller reservoir at a higher elevation than San Vicente Reservoir, along with a tunnel system to connect the two reservoirs and an underground powerhouse. The powerhouse would contain four 125 MW reversible pump-turbines capable of lifting water to the upper reservoir and generating power as it flows down.
During peak energy demand, water would flow down to generate carbon-free power. During off-peak periods, including daytime when renewable wind and solar power supplies exceed demand, water would be pumped to the upper reservoir. The project would support electrical transmission grid operations that are essential to integrating renewable wind and solar power supplies.
The potential facility would supplement the region’s energy needs with up to 500 megawatts of renewable power during peak demand periods and generate stored energy for up to 8 hours. Power generated at the San Vicente facility would be delivered into the energy grid via a new connection to the Sunrise Powerlink.
The concept at San Vicente is for a closed loop, off-stream system in an upland area with no natural water body. The exchange of water between the two reservoirs would not consume water or interfere with existing water supply, water quality, fisheries, or recreational uses of the San Vicente Reservoir.
Partnering with City of San Diego
San Vicente Dam and Reservoir are owned and operated by the City of San Diego. The Water Authority completed the San Vicente Dam Raise in 2014, and owns the additional storage capacity created by the expanded reservoir. The two parties jointly prepared a joint Preliminary Application Document and a Notice of Intent for submission to the Federal Energy Regulatory Commission, the agency responsible for approval of all energy generation projects on July 28, 2015. The preliminary application outlines the plan for implementing the project, identifies what environmental resource studies are needed, and is a precursor to submitting a formal FERC license application.
Winter 2017/Spring 2018
|Negotiate draft Project Delivery Agreement Terms and Conditions|
|Spring 2018||Present Project Development Agreements to San Diego City Council and Water Authority Board of Directors|
|Spring 2018||Submit Interconnection Application to California Independent System Operater|
|Spring 2018||File FERC Preliminary Permit Extension Request|