Regulators in the US have warned a major shake-up of safety standards may be needed for home battery storage systems in the wake of an explosion at a lithium-ion grid-scale battery storage facility in Arizona.
The Arizona Public Service (APS) utility told BEST Battery Briefing an investigation into what caused the “catastrophic failure” of the 2MW/2MWh system at its McMicken facility last month in the city of Surprise was still under way.
But members of the Arizona Corporation Commission (ACC), which has oversight of the utility, have asked that a member of its staff be involved in the probe— in case lessons learned highlight a need to review BESS safety standards for homes, businesses, and for revised guidelines for firefighters and first responders called to tackle future incidents.
ACC commissioner Boyd Dunn (pictured) told APS bosses: “Batteries are our future so your investigation is going to be critical.”
“I do have a concern that we take this opportunity to see if we need to address other issues,” Dunn said. “Do we need to look at building codes for batteries in homes and are all building codes up to the level we feel are going to provide the safety we need?”
Dunn said the “unique” nature of lithium-ion batteries and their risk of catching fire might mean “reaching out to the fire department to look at their procedures and see what can be done differently in future”.
APS president Jeff Guldner told commissioners in an update on the McMicken explosion: “Lithium-ion batteries are not new. They come in different scales for residential storage and (ours) are large installations, but we certainly share your concern that, as this technology becomes more important in the operation of the electric grid, we understand how to use it safely. That will be a major focus of the investigation.”
Some 800MW of batteries are connected to the US electric grid, “so it's very important that we conduct this investigation… because this is where the industry is going”, Guldner said.
APS vice-president of transmission and distribution operations, Jacob Tetlow, confirmed the McMicken BESS was designed and supplied by AES, now part of energy storage group Fluence, and contained batteries made by South Korea’s LG Chem. A “twin” unit to the one involved at McMicken and a separate BESS operated by APS had been taken off line “as an abundance of caution”, the utility said.
Last month, BESS manufacturers and users backed an industry-led initiative in the US to “prioritise safety” in the production and operation of equipment.