Overheating Incident Takes 300-MW California Storage Facility Out Of Service

Vistra on Sept. 7 said that it has begun a preliminary assessment of Phase I of its Moss Landing energy storage facility in California following an overheating incident that impacted a limited number of battery modules and occurred on the evening of Sept. 4.

Phase I of the Moss Landing facility is a 300-megawat (MW)/1,200-megawatt hour (MWh) system and is out of service, while Phase II of the facility (100 MW/400-MWh), which is located in a separate stand-alone building, remains operational.

In the wake of the overheating incident, teams from Vistra, battery manufacturer LG Energy Solution, engineering and construction firm Fluence, and other external experts were conducting initial walkthroughs of the building in order to gather information and begin their investigation into the root cause of the issue. The North County Fire Protection District of Monterey County is assisting with the investigation.

The teams are in the early stages of this investigation and expect that it will take some time to fully assess the extent of the damage before developing a plan to safely repair and return the battery system to operation. “We are working with our partners to ensure all necessary safety precautions are in place to minimize any risk during this process,” Vistra said.

On Sept. 5, Vistra said that there are multiple layers of safety integrated into the battery facility and the risk mitigation and safety systems worked as designed, detecting these modules were operating at a temperature above operational standards and triggering targeted sprinkler systems aimed at the affected modules. As a result, the overheating was controlled and contained without the need for outside assistance.

“However, consistent with Vistra’s incident response planning and out of an abundance of caution, the Moss Landing team did ask the local fire department, North County Fire Protection District of Monterey County, to respond to the site. Importantly, there were no injuries to the facilities’ workers as a result of the incident and the situation is contained to the facility with no harm to the community,” the company said.

The 100-MW/400-MWh Phase II expansion is operating under a 10-year resource adequacy agreement with investor-owned Pacific Gas and Electric Company (PG&E). The Phase I project has a similar 20-year resource adequacy agreement with PG&E.

The Phase II expansion project was completed in July 2021.

Vistra is an integrated retail electricity and power generation company based in Irving, Texas. According to the company, it is the largest competitive power generator in the U.S. with a capacity of approximately 39,000 MW powered by a portfolio that includes natural gas, nuclear, solar, and battery energy storage facilities.