PHOENIX — A state regulatory panel questioned Arizona Public Service executives about an explosion last week that injured more than a half-dozen firefighters.
APS says it received an alarm about its two-megawatt battery next to its McMicken Energy Storage facility near Grand Avenue and Deer Valley Road around 5 p.m. Friday. Technicians and firefighters responded, and roughly three hours later there was an explosion that injured eight firefighters.
In front of the members of the corporation commission, which has oversight over the utility, officials said there had been previous issues with similar technology that had since been corrected.
"We want to be transparent in the sense that we have had battery challenges in 2012," vice president Jacob Tetlow said, referring to a fire in Flagstaff that year. "The conclusion of the investigation is there was room for improvement in the quality of the [fire] suppression system. Those gaps were identified and integrated into the new [facilities]."
"Things happen that are very unfortunate but the important part is that we learn and we get better and we improve," vice president Jacob Tetlow said in an interview outside the commission chambers. "This will be an opportunity to learn and improve and get better."
APS officials said it was too early to assess the performance of the fire suppression system in the case of last week's explosion and the incident remained under investigation by the utility, firefighters, and third-party consultants.
As of Tuesday, two of the eight firefighters remained hospitalized and were expected to recover.
In response to the explosion, APS said it had deactivated its other batteries, including a sister unit to the one that exploded housed at a site near Desert Oasis Boulevard and Sun Valley Parkway, out of caution until the investigation is complete.
"We have de-energized, so discharged, our Festival Ranch battery and essentially placed that offiline while we conduct this investigation," president Jeff Guldner said. "We want to make sure we understand what happened before that battery is put back into service."