Arizona Public Service (APS) has launched an investigation to determine the cause of a fire at its McMicken battery energy storage site that injured four firefighters.
The utility says that firefighters and hazardous material units responded to reports of smoke from the McMicken energy storage facility, one of two identical 2 MW /2 MWh grid-scale batteries installed by APS in 2017, on April 19. It put the initial cause of the fire as “equipment failure” but added that it has launched an investigation with first-responder representatives, manufacturers and third-party engineering and safety experts.
“A thorough investigation will help us determine what exactly failed and why,” APS said in a statement. It added: “Importantly, until the investigation is completed, we cannot speculate about the root cause of the incident – whether it was the battery unit itself or another grid component.”
Four firefighters were hospitalized as a result of the incident. According to local media, the firefighters were inspecting the lithium-ion batteries when they were hit with an explosion. Several of the firefighters received chemical burns.
The battery system was supplies by AES, which last year merged its energy storage business with Siemens to create Fluence.
“We greatly appreciate the hard work and bravery of the first responders who were involved,” said APS. “Our hearts go out to the firefighters injured in the line of duty. Their health, safety and recovery are our top priorities.
“The investigation will help us learn all we can from what happened so that we can apply those lessons to how we move ahead. It is too early to know when we will complete the investigation, but we will act quickly to apply the safety lessons learned from this incident.”