The San Diego County Water Authority and City of San Diego, which jointly hold a preliminary permit for a 500-MW pumped storage hydro project, on July 28 filed with the Federal Energy Regulatory Commission a completed Pre-Application Document (PAD), a formal Notice of Intent (NOI) to file an application for an original license and a formal request to utilize FERC’s Traditional Licensing Process (TLP).
The proposed San Vicente Pumped Storage Project would be a closed-loop pump storage system consisting of an existing reservoir, a new upper reservoir to be formed by three dams, conveyance tunnels, a powerhouse containing four 125-MW reversible pump turbines, and a five-mile, 230 KV double-circuit power transmission line.
It would be located near the community of Lakeside within San Diego County, California. The project will be configured using the existing San Vicente Reservoir as the lower reservoir. The proposed upper reservoir site (Foster Canyon) site is located approximately 0.5 miles northwest of the San Vicente Reservoir.
In addition to the two reservoirs, the San Vicente Project would consist of new inlet/outlet structures, a powerhouse cavern, pipeline/tunnel connecting the upper and lower reservoirs to the powerhouse, access and cable tunnels, new power transmission lines, access roads, and other related facilities.
On May 14 of this year, the FERC issued the 36-month preliminary permit to the Water Authority and City for this project. The preliminary permit secures and maintains priority of application for a license for the project under the Federal Power Act, allowing the Water Authority and City time to collect the data and perform the acts required to determine the feasibility of the Project and to support an application for a license. Such studies have been ongoing, the July 28 filing noted.
A new dual-circuit 230-kV transmission line will extend approximately five miles from the powerhouse generators to the existing Sycamore Canyon Substation owned by San Diego Gas & Electric (SDG&E) for interconnection to the regional transmission grid system. This new transmission line will generally run parallel to SDG&E’s recently completed Sunrise Powerlink transmission line. SDG&E has determined that the Sycamore Canyon Substation, which was constructed as a part of the Sunrise Powerlink Project, has sufficient capacity to accommodate the hydro project.
Annual generation for the four 125-MW units will average 1,022 Giga-Watt hours (GWh), assuming the daily energy storage of 4,000 Mega-Watt hours (MWh) and operating at 70% of its total capacity.
Noted the July 28 filing: “Hydroelectric pumped storage is a reliable and cost-effective technology that enables utilities to store electrical energy in the form of the gravitational potential energy of water produced during surplus generation and at periods of low demand and utilize that stored energy during periods of high demand and for transmission grid operations. Water will be pumped from the lower reservoir to the upper reservoir during periods of surplus power generation and/or low electrical demand. The water placed in the upper reservoir represents stored energy that can be used to meet capacity needs during periods of high demand as the water is passed through a hydraulic turbine from the upper to lower reservoir. The cycle is then repeated to balance demands on the regional or local power grid. The Project is also expected to participate in the ancillary services market and provide flexible generating capacity to maintain grid stability resulting from the increase in intermittent renewable energy generation.”
A project contact is: Frank Belock, Deputy General Manager, San Diego County Water Authority, 4677 Overland Avenue, San Diego, California 92123, Phone: (858) 522-6600.