This is the third part of a series examining the McMicken battery fire of 2019 and its ramifications for the energy storage industry. This installment addresses the lessons for fighting fires at battery facilities. Part I covered how battery developers have enhanced fire safety in battery plant designs since last year, and Part II tackled the quest to identify the root cause of the incident.
The 2019 lithium-ion battery fire in Surprise, Arizona warned the world of the dangers new grid infrastructure can pose to humans.
The emergency response plan provided to local firefighters lacked crucial details about the threat they were facing. And the young energy storage industry had never experienced what was about to happen: a gaseous explosion so powerful that it flung responders dozens of feet through the air.
The mere knowledge that this is possible changes the risk profile of grid batteries; as long as firefighters know what happened in Arizona, they’ll be able to approach future incidents with a greater level of caution.
Battery developers have already improved their safety designs in the hopes of preventing a repeat of the McMicken disaster, which sent four first responders to the hospital. But an investigation by Underwriters Laboratories’ Firefighter Safety Research Institute could spur a similar upgrade in the approaches first responders use when dealing with grid battery facilities — and in how battery developers deal with first responders.
“Nobody wants batteries to stop — we know we need the technology; the communities need them to move the world forward,” said Stephen Kerber, director of FSRI and co-author of the report. “But I think we can find a compromise of safety and getting fire chiefs confident.”
The specter of the McMicken explosion has canceled battery development in at least a few different cases, as local residents and fire chiefs worried they would be ill equipped to handle similar conflagrations. Proactive outreach to local firefighters has become crucial to the success of new battery projects.
Plenty of other projects show that it is possible for battery developers to meet the safety needs of local communities, and may even leave them better off. Batteries are expected to play an increasingly pivotal role in complementing renewable power in a low-carbon grid. But that will only happen if developers earn and maintain the trust of firefighters around the country.
What went wrong in Arizona
The report, released in July, paints a picture of responders doing their best to operate in an information vacuum.
Laboratory chemists know what happens when lithium-ion batteries enter “thermal runaway,” in which one cell overheating ignites a neighboring cell until a whole rack burns up. And battery experts had found that this emits gases which, if trapped in a confined space and exposed to the right mix of heat and oxygen, can explode.
But high-level battery science was not in the toolkit of the firefighters dispatched to a call about smoke emanating from an Arizona Public Service facility outside of Phoenix. Even the hazmat technician curriculum did not include basic energy-storage-related hazards, the report found.
Nor did it advise on what to do about the foul-smelling, low-lying white vapor cloud emanating from the container.
“They had just about every hazmat expert in the entire Phoenix region on the phone trying to figure out what to do about this,” Kerber told GTM. “The emergency response plan didn’t really cover thermal runaway, so there was no playbook.”
The fire department had meters to detect for typical gas leaks, so they cleared out a 300-foot perimeter and measured with what sensors they had. They noticed high levels of carbon monoxide and hydrogen cyanide at the scene.
But the crew did not have sensors that would pick up the concentration of explosive gases building up inside the container. Doing so typically requires a larger piece of equipment rather than a handheld device, Kerber said. The battery facility also lacked such a meter, and even if it had one, the communications feed cut out after things started going wrong.
“The fire service is there to stabilize the incident,” Kerber said. “They want to be able to mitigate it and turn it back over to the building owner.”
That desire to stabilize the incident drove the decision to open the door to the container. The vapor cloud had diminished, and the measurable hot zone in the enclosure seems to be getting smaller as well. Four people went in to open the door, collect additional readings and gauge whether the situation posed an ongoing threat.
Even after the door opened, things seemed fine. The firefighters saw no signs of active fire and took measurements for about three minutes before the explosive release of pressure known as a deflagration event. The blast threw one man 73 feet through a chain-link fence, ripped off the team’s helmets and masks, and rendered all four unconscious.
“At the end of the day, the fire department owns the decision to act,” Kerber said. But, he added, “All the way up until the deflagration itself, the mindset was things were getting better; the incident was stabilizing.”
Spreading knowledge across a fragmented fire service
Safety codes have evolved since the McMicken system was built, and the electricity industry and firefighters now have access to a wealth of information that the responders in Arizona did not. But one risk is that the lessons will not be disseminated uniformly among the nearly 30,000 fire departments across the U.S.
“The fire service in the United States is very fragmented,” Kerber said. “There’s no one mechanism to reach them all.”
Grid batteries are still a relatively new phenomenon, with installations clustered in a few states. But annual installations are expected to be seven times larger in 2021 than they were in 2019, and that influx will bring batteries to new places. Urban areas like Phoenix may have well-resourced fire departments with dedicated hazardous materials teams. But rural areas with smaller staffs and budgets have to determine their own comfort level with lithium-ion batteries. And the explosion in Arizona already changed some minds.
A 140-megawatt battery development in Valley Center, north of San Diego, failed to win local permitting approval in July after community members objected to the perceived threat.
“Just last year, there was an explosion in Arizona that injured four firefighters and resulted in Arizona Public Service shutting down two other facilities,” one resident testified at the planning meeting, according to local newspaper Valley Roadrunner. The developer’s insistence that any fires would be contained at the module- and container-level failed to sway the vote.
Enel Green Power ran into similar issues trying to secure a permit for a 100-megawatt battery in rural Littleton, New Hampshire. Testimony included a fire chief showing photos purported to be from the APS fire, which Enel said were not in fact from that event, according to local paper the Caledonian-Record. Enel withdrew its application in February.
“'Nimbyism' is definitely a huge factor in the energy industry, and we’re seeing it rear its head with energy storage,” said Daniel Finn-Foley, energy storage director at research firm Wood Mackenzie. But local objections are unlikely to halt the energy storage industry as a whole. “It will affect individual projects, but as a macro trend, I think the momentum is too high.”
Make a good impression
Battery developers can defuse tension with proactive outreach to communities and by actively investing in local safety.
Strata Solar is building a 100-megawatt/400 megawatt-hour battery in an unincorporated part of Ventura County, north of Los Angeles. Development protocol required testing whether local water infrastructure was up to county code; it was not, so Strata paid to upgrade it.
“The fire department was really excited about that,” said Will Mitchell, Strata’s vice president of business development for the West. “When they are in that area, they now have reliable access to water.”
The investment had nothing to do with the nature of battery storage, Mitchell added. The plant’s Tesla Megapack batteries are designed to contain any fires and vent gases to prevent explosions; the plan is that if an adverse event happens, firefighters would not need to intervene. But the water upgrades will help them fight fires in the surrounding area.
Mitchell himself serves as a volunteer firefighter and elected fire commissioner in Marin County, north of San Francisco. That perspective informs his engagement with local permitting agencies during the battery development process.
“Like anything else in development, if you address it early and take a proactive approach supported with facts and data, then in my experience, public officials and regulators will give it a fair analysis,” he said. “If you’re meeting or exceeding those codes, then you should be able to become part of the community.”
Most people have never encountered a grid battery, so their first impression of the technology may be from frightening news reports out of place like Surprise. Developers have to contextualize the current risks while explaining the ways batteries can benefit surrounding communities even as they help the broader electricity system.