Pacific Gas and Electric Company (PG&E) has successfully completed a technology demonstration project to explore the performance of battery storage systems participating in California’s electricity markets.
The project, funded by California’s Electric Program Investment Charge (EPIC) program, began in 2014 and utilized PG&E’s 2 megawatt (MW) Vaca-Dixon and 4 MW Yerba Buena battery storage systems to provide energy and ancillary services in California Independent System Operator (CAISO) markets. The Vaca-Dixon system is the first battery storage resource in California to participate in the market. The Yerba Buena system is the first battery storage resource to both participate in the market and serve a reliability function supporting PG&E’s distribution system in the event of a disturbance or outage.
The chart plots scheduled (grey) vs actual (green) battery performance. The difference between the lines is primarily due to parasitic loads in the battery system and other losses, and curtailment of charge power as the battery nears 100% SOC. This is explained in greater detail in the Section 4.5.1 Resource-Specific Challenges. The differences between the green and grey lines also represent deviations from the DA schedule, termed “uninstructed deviations”, and settled in the Real-Time (RT) market at the RT clearing price.
PG&E shared results of the project in a 71-page comprehensive report, which includes detailed overviews of the market participation process and the unique challenges to operating battery resources in the electricity markets.
“We see great potential for energy storage systems to benefit Californians. Through this demonstration PG&E has addressed multiple barriers and gained incredible operational experience with battery storage. We’ve identified and resolved challenging implementation issues, established a new interconnection process, and developed an automated dispatch system that will serve as a platform for continued market participation,” said Kevin Dasso, vice president, Electric Asset Management, PG&E.
Key project accomplishments include:
- Developing and deploying a scalable technology platform to automate the response of current and future PG&E battery storage resources to CAISO.
- Quantifying financial performance of battery systems in California energy markets.
- Identifying opportunities and challenges associated with operating dual-use energy storage systems.
The project also included tasks to put in place processes and technology to enable the efficient operation of battery storage resources in the markets.
“When we started this project, there were no batteries participating in the CAISO markets, so the only information available about battery market performance came from economic models. So much goes into deploying a completely new type of technology in the CAISO market, and PG&E developed new workflows and procedures, and a new IT technology platform to make it all work. We’ve successfully tested how batteries actually perform in the markets, substantially helping to inform the conversation about energy storage in California. Now that we have put these elements in place, it will be much easier to bring future battery systems online,” said Manho Yeung, senior director, Transmission Asset Management, PG&E.
In 2017, PG&E will utilize the Yerba Buena battery, located in the San Jose foothills, for another EPIC technology demonstration involving the coordination of 3rd-party distributed energy resources (DERs) — such as residential and commercial solar — using smart inverters and battery storage controlled through a distributed energy resource management system (DERMS).
The full report can be downloaded from PG&E’s EPIC Program website:https://www.pge.com/pge_global/common/pdfs/about-pge/environment/what-we-are-doing/electric-program-investment-charge/PGE-EPIC-Project-1.01.pdf
Filed Under: Energy storage, News
