GrokSurf's San Diego

[Revised to clarify SDG&E is a potential, not certain, partner]

These three slides show a pumped storage operation already functioning at Lake Hodges and Olivenhain Reservoir.

A $149,920 contract was awarded to Black & Veatch Corporation to perform an economic and financial study, and another $59,667 contract went to Navigant Consulting to provide an independent review and give advice on next steps, for the San Vicente Pumped Storage Project.

The contracts were awarded by the San Diego County Water Authority (SDCWA) at last Thursday’s (October 24) board meeting. SDCWA will also enter into a Memorandum of Understanding with the City of San Diego for joint participation in the implementation of the study. The City will pay an equal share of the study’s cost.

In brief, the pumped storage project would entail construction of a small reservoir at an elevation above San Vicente reservoir. Water from San Vicente reservoir would be pumped to the upper reservoir at night taking advantage of non-peak power rates, then released back to San Vicente during the day, generating electricity to that could be sold to an entity such as SDG&E at higher daytime rates. As a potential purchaser, SDG&E would gain a new reliable stored energy source to help manage fluctuating demand and SDCWA would generate some profit. The project is described in greater detail in this story.

(While the City of San Diego owns San Vicente Reservoir and the dam, SDCWA paid for construction of the dam raise project and owns rights to the resulting additional reservoir capacity)

The proposed facility would have a 500 MW capacity.

Why pumped hydro energy storage?

Wind and solar installations are becoming increasingly important sources of electricity for our power grid. Wind and solar energy production is highly variable, however, and can’t reliably provide a specified amount of energy on demand. Stored energy facilities can help moderate fluctuating power supply situations as well as be on call for periods of peak demand.

SDCWA already has a functioning pumped hydro storage facility at Lake Hodges operating under a power purchase agreement with SDG&E. Water is pumped back and forth between Hodges Reservoir and Olivenhain Reservoir generating up to 40 MW of electricity. The three slides shown here illustrate that arrangement (slides are from the SDCWA PowerPoint presentation at the meeting).

Integrating renewable energy sources and improving grid reliability is why the California Public Utilities Commission (CPUC) just ruled on October 17 that PG&E, SCE, and SDG&E must procure 1,325 MW of energy storage, to be installed and delivered by the end of 2024. It also ruled that community choice aggregators and electric service providers must procure 1% of their annual peak load from stored energy by 2020.

A possible sticking point

However, the CPUC ruling also said that pumped hydro storage facilities producing more than 50 MW of power cannot be counted towards its procurement targets.

Pumped hydro storage clearly stores energy and could benefit the electric grid, so why should it be ruled out just because it produces more than 50 MW?

CPUC’s rationale was that its policies and procedures must “…provide opportunities for the cost-effective deployment of all types of energy storage technologies. In order to achieve this, however, there must be a limit on the size of pumped hydro storage systems…” because “…the sheer size of pumped storage projects would dwarf other smaller, emerging technologies; and as such, would inhibit the fulfillment of market transformation goals.”

Future outlook

Even within CPUC there was some disagreement about large pumped storage projects and the decision may be revisited. Commissioner Mark Ferron and President Michael Peevey wrote in their Concurrence: “We are concerned that ratepayers may be missing an opportunity to benefit by limiting the size of pump storage under this decision. We hope that a fix can be found.”

At the board meeting, members of SDCWA’s Engineering & Operations Committee concerned about CPUC’s ruling expressed hope that the feasibility study would consider the strategic implications of the CPUC ruling and that SDCWA’s lobby in Sacramento might do more outreach.

The feasibility study is expected to be completed sometime in spring 2014.

San Vicente marina facilities update

Also during the SDCWA board meeting, a contract for work on the new marina facilities at San Vicente Reservoir in the amount of $22,882,639 was awarded to Pulice Construction. The new marina is being built because the dam raise project will bring higher water levels

Work will include additional grading and rock slope protection for the hillsides surrounding the marina, export of excess material, staining for slopes along the marina access road to match the surrounding hillsides, electrical work for the potable water supply system.

Once work on the marina is completed, currently scheduled for late 2014, SDCWA will coordinate with the City to open it and the reservoir to the public. The opening date will depend on how quickly imported water can be obtained to fill the reservoir. At least 50,000 acre-feet will be needed to open the marina.

On the left, the new marina and boat ramp under construction at San Vicente Reservoir is in the quarry that was created to supply material for the dam raise project. The dam isn’t visible but is to the left of the marina. The reservoir’s “bathtub ring” shows the high water mark behind the old dam (water level is lower now for construction). With the raised dam, the water level will be considerably higher, possibly submerging most of the peninsula on the right. The view is from a trail in the OakOasis Open Space Preserve.