Energy Storage

Calif. Community Choice Aggregator Signs PPA Tied to Compressed Air Energy Storage Project

California community choice aggregator Central Coast Community Energy (3CE) has signed a 25-year power purchase agreement for a compressed air energy storage project with Hydrostor.

The nearly $1 billion power purchase agreement calls for the delivery of 200 megawatts (MW), 1,600-megawatt hours (MWh) of energy storage to 3CE from Hydrostor’s planned Willow Rock Energy Storage Center that will use the company’s Advanced Compressed Air Energy Storage (A-CAES) technology. Hydrostor says the project, when completed, will abate up to 28 million metric tons of carbon dioxide over its lifetime.

The Willow Rock project is sited just outside Rosamond in Kern County and will eventually have the ability to deliver 500 MW of clean power for up to 8 hours, Hydrostor said.

The facility is designed to be charged using surplus renewable energy and to discharge to the grid at times of high demand, reducing the need to build new peaking power plants and deferring the need for new transmission lines, Hydrostor said, noting that the facility will have a footprint of less than 100 acres, which is far smaller than a comparable pumped hydro power facility, which represents the overwhelming majority of long duration energy storage on the market today.

Hydrodstor’s technology combines elements of a compressed air storage system with a pumped hydro system. The process stores energy as compressed air but captures and stores the heat of compression for future use. The compressed air is stored in a purpose-built underground cavern that uses a water reservoir to maintain constant pressure. The facility discharges energy by reversing the process, using the stored heat and pressure to power a conventional turbine generator. The system has no performance degradation over its 50-year plus expected lifetime, Hydrostor said.

Hydrostor said its technology offers the same services as a natural gas plant while having zero emissions because it uses surplus electricity as fuel. The company is targeting high value grid applications such as transmission deferral and fossil fuel generation replacement.

The PPA with 3CE is the first of several Hydrostor hopes to sign to allocate the full 500-MW capacity of the Willow Rock project. The company said it is in discussions with several parties for the balance of the total output.

Central Coast Community Energy is a public agency that sources electricity from clean and renewable energy resources to serve 447,000 residential, commercial, and agricultural customers in Monterey, San Benito, San Luis Obispo, Santa Barbara, and Santa Cruz counties.

The American Public Power Association has initiated a new category of membership for community choice aggregation programs.