Shorted lithium-ion batteries and subsequent smoke are believed to have triggered the shutting down of the world’s biggest energy storage system— early evidence from power generation firm Vistra Energy suggests.
Leaked water is believed to have caused the batteries to short and prompted the early detection safety system to activate in the 100MW Phase II building at the Moss Landing Energy Storage Facility in Monterey County, California, US late on 13 February.
The building’s suppression system contained the event without the need for the outside assistance; however the system operator contacted off-site emergency response “out of an abundance of caution”.
Vistra said there is early evidence that water hoses leaked and that some batteries shorted, creating smoke in the building.
Vistra’s statement read: “There are no injuries to personnel. An investigation is underway to determine what caused the safety system to activate.
“While this is in its very early stages, what we know is the water-based suppression system released water that contacted some batteries.”
Battery short causes shutdown
The Texas, US firm’s 300-MW Phase I facility was not affected by Sunday’s incident, but remains off-line following a “overheating” incident last September.
The system is made up of more than 4,500 stacked battery racks or cabinets, each containing 22 individual battery modules manufactured by LG Energy Solutions.
The Vistra statement read: “We have been in the process of incrementally bringing the Phase I facility back online but have decided to pause restart activities while we assess the Phase II incident and will incorporate any learnings.”
In January, Vistra entered into a 15-year resource adequacy agreement with Pacific Gas and Electric Company (PG&E) for a new 350MW/1.4GWh battery system; this will complement the existing 400MW/1.6GWh of energy storage capacity already at the site.