The potential project is expected to not only increase renewables penetration, but can also lessen pressure on water rates throughout the region by using existing infrastructure.

The project would consist of closed-loop interconnection and pumping system between the existing reservoir and a new smaller reservoir located uphill.

With a potential to produce 500MW of renewable energy, water from the downhill can be pumped uphill during off-peak times. This could in-turn be used when there is a high demand for power, when solar or other renewable sources are unavailable or when energy demand and electricity costs are higher.

Water Authority’s Board of Directors chair Mark Muir said: “This potential project is an exciting and innovative opportunity to optimize our water facilities to benefit our ratepayers while helping the region as a whole meet its energy needs.

“The competitive bidding process will help ensure this potential project delivers maximum value.”

The project can also bring grid stability in the region and helps in integrating large new suppliers from other renewable electricity sources into the grid.

San Diego County Water Authority expects that interested parties for the Requests for Proposals (RFP) must provide details of full-service teams to perform an operational project and it expects to evaluate proposals this fall.

The size of the project is also of significance. A 500MW project with 5-8 hours of energy storage can help in reaching renewable energy goals set by the state.

Image: San Diego County Water Authority seeks propels for 500MW pumped storage project. Photo: Courtesy of Yongkiet/