Energy storage for market operations a success

PG&E successfully tested how large-scale battery storage systems perform in the California Independent System Operator (CAISO) market. Our 2 megawatt (MW) Vaca-Dixon and 4 MW Yerba Buena battery storage systems provided energy and ancillary services in CAISO markets. The Vaca-Dixon system was the first battery storage resource in California to participate in the market. The Yerba Buena system, in San Jose, was the first battery storage resource to both participate in the market and serve a reliability function supporting PG&E customers in the event of a disturbance or outage.

The project was funded by the Electric Program Investment Charge (EPIC) program.


Outcomes and learnings

  • The project successfully built integration systems to allow Vaca Dixon and Yerba Buena batteries to participate in real-time and day-ahead CAISO markets, which were the first utility-owned battery storage resources to participate in the Non-Generator Resource (NGR) market.
  • The project determined that Frequency Regulation was the highest value product, compared to potential energy arbitrage revenues available at this time.


Our progress continues

  • Two batteries tested continue to operate in production with the CAISO market (4 MW Yerba Buena in San Jose, 2 MW Vaca Dixon in Vacaville)
  • Learnings formed foundation for additional storage agreements through future Energy Storage RFOs


Review the final report

Find out more about the project’s objectives, approach, results and lessons learned.

Download Pacific Gas and Electric Company EPIC 1.01 (PDF, 5.5 MB)

Learn more in featured articles

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