Author(s): Angelo Verzoni. Published on May 16, 2022.

ESS Prep

Battery-powered energy storage systems are cropping up everywhere. For the fire service, improved ESS training and regulation are keys to a safe coexistence with this evolving and complex hazard. Efforts underway in the Boston area, as well as established procedures in New York City, could provide other jurisdictions with valuable guidance.


New England is one major cold snap away from its power grid crumbling. That was the grim message delivered by Gordon van Welie, the CEO of ISO New England, during a video briefing for the company in December. ISO New England maintains the power grid in all six New England states.

“People don’t know how closely we’re operating to the edge,” Van Welie said, citing the region’s reliance on what he called a “fragile” supply chain of natural gas. “We need to put a spotlight on this problem.” He pointed to what happened in Texas less than a year before, when cold weather overwhelmed the state’s grid, triggering widespread power outages that left more than 150 people dead.

Explore resources from Electrical Safety Foundation International on ESS safety for first responders
• Read an NFPA Journal feature story about a 2019 ESS explosion in Arizona
• Learn what changes are in store for the newest edition of NFPA 855

In light of Van Weile’s warning, the Boston Herald delivered a partially tongue-in-cheek message to readers: “Start chopping wood.”

But for some New England properties, a loss of power grid energy isn’t the end of the world and would require no manual labor beyond the flip of a switch. That’s the case for the University of Massachusetts (UMass) Boston, which in 2020 completed a project to add energy storage systems (ESS) to its campus on Dorchester Bay, about three miles south of downtown Boston. The campus houses vast arrays of solar panels that feed energy into the systems, where it’s saved in batteries and can be deployed whenever the region’s power grid becomes overwhelmed. The reserve of energy keeps the lights on at UMass while saving valuable grid power for the rest of the city.

But what happens if a fire breaks out on campus and threatens the energy storage systems? What if a chemical process known as thermal runaway occurs inside the ESS batteries, in which they essentially continuously overheat and over-pressurize and are prone to fires, arc-flashing, off-gassing, and sometimes explosions?

These are the kinds of questions that worry Marty McCormack, a deputy chief in charge of training at the Boston Fire Department (BFD). “I remember the first time I saw a live burn of a lithium-ion battery put on by UL,” he told NFPA Journal in an interview in February. “Holy cow, what a noise it makes. What a furious fire it makes. I watched that and said, ‘Boy, we really have something here that could hurt people.’”

Vast arrays of energy storage systems, like this one in California, are cropping up all over the globe, providing added resiliency to power grids. Experts say more training, partnerships, and other resources are needed to better prepare firefighters for dealing with this emerging and complex hazard.  GETTY IMAGES

Since UMass is a state-run organization, McCormack said, the BFD wasn’t involved in the permitting process for the design and installation of the ESS equipment on the UMass Boston campus, even though the department could be called there to respond if something goes wrong with that equipment. It’s a problem for fire departments across the country, McCormack said. ESS installations often fall under a patchwork of state and local regulations, potentially leaving departments in the dark on hazards that could be hidden in their own backyards. Between counting smaller-scale ESS attached to single-family homes and larger-scale commercial configurations like the ones at UMass, the number of ESS in Boston is anyone’s guess. “We have no idea,” McCormack said.

Compounding that problem, when departments arrive on the scene of a fire involving an ESS, there’s little formal guidance on how to approach the situation: Do you use foam or water? Should you try to vent the structure? How long do you need to stay on the scene? “If we got an alarm for an ESS fire right now, it’s going to be a crapshoot,” said Chris Towski, a lieutenant in the fire department for the city of Cambridge, across the Charles River from Boston. “Don’t get me wrong—we’ve gotten a lot better over the years. But we’re still a work in progress.”

One big step forward is slated for later this summer, when McCormack finalizes a set of standard operating procedures (SOPs) he’s writing for firefighters responding to ESS incidents. The idea for the SOPs—which McCormack and Towski believe are the first of their kind in the United States—emerged from a partnership between the Boston and Cambridge fire departments about a year and a half ago. Additionally, the City of Boston is accepting bids for a project to install solar panels and an ESS at a fire department training facility on Moon Island, about two miles east of the UMass Boston campus. “It will give any firefighter in Massachusetts a hands-on look at this technology,” McCormack said.

Experts say efforts like this to better educate and train firefighters on ESS incidents are key to addressing the need for enhancing responder preparedness for ESS nationwide. Addressing the issues involved in the regulatory aspects of ESS design, installation, and management could be a bit more challenging. But there’s hope that with more widespread adoption of NFPA 855, Standard for the Installation of Stationary Energy Storage Systems, coupled with increased attention to collecting and accessing data, those challenges will ease, too. ESS safety will be the topic of several education sessions at the NFPA Conference & Expo® in Boston in June.

“We don’t want to be the bad guys, saying you can’t have an ESS,” said Towski, who serves on the NFPA 855 technical committee. “We just have to improve the regulatory piece of it, and we need quick-hitting, bulleted items telling firefighters what to do if they respond to incidents involving ESS.”

‘The new hazmat’

As of early 2022, nine states across the country had goals in place to achieve energy storage capabilities of varying degrees by 2030—from a massive 6-gigawatt goal in New York to a 400-megawatt goal in Maine. These goals will be met by installing dozens of ESS, most of them battery-powered, across each state over the next several years.

While there’s little scientific data on how often ESS batteries overheat, catch fire, or explode in the US or globally, it does happen. More than 30 ESS battery fires have been documented in South Korea alone since 2017, for example. Perhaps the best illustration of the potential dangers of ESS to first responders occurred in April 2019, when ESS batteries began overheating and off-gassing in Surprise, Arizona, at a facility owned by the utility company Arizona Public Service. A subsequent explosion at the site severely injured four firefighters. Investigations later revealed that firefighters opened a door attached to the ESS, allowing oxygen to mix with the chemicals being off-gassed, creating the right conditions for a blast.

In 2019, an energy storage system in Surprise, Arizona, exploded, injuring four firefighters—nearly killing one.  COURTESY OF PEORIA FIRE-MEDICAL DEPARTMENT

It’s situations like these that McCormack and Towski want their fellow firefighters to be prepared for.

“Something that’s always said on the scene of a fire is ‘Fire’s knocked down, companies are overhauling,’” McCormack said. “And overhauling means you’re opening things up, exposing leftover fire spots. With an ESS, doing that could be deadly. So these SOPs and other training efforts will really be about teaching firefighters to wait for things to burn through before dousing them with water or making sure something’s not going to explode if you open it.”

According to Towski, simply alleviating concerns over mixing water with batteries will go a long way toward establishing better responder preparedness for ESS. “We have this hysteria over mixing water with any kind of electricity,” he said. “So one of the biggest things we need to get our members comfortable with is just realizing that yes, you can use water very effectively on these fires, and in fact that’s what you should be using. Every engineer says the best thing for putting these fires out is water.”

“In Boston, we’re lucky because we have tons of water,” McCormack added. “We have the entire Atlantic Ocean if we need it.”

When McCormack finalizes the SOPs, they’ll be made available to any department that wants them. But even then, McCormack cautions, they will be subject to change and by no means final. “They’re not very scientific,” he said. “They’re really just my best guess based off my own department’s and other departments’ experiences with ESS and other battery incidents like electric vehicle fires.” In other words, continued research into how best to respond to incidents involving ESS and other complementary training resources will be needed.

“There is absolutely a need for more and updated training,” said Bob Sullivan, a regional director at NFPA whose coverage area includes Arizona, where the 2019 ESS explosion occurred. “It’s a huge need that’ll be ongoing for years.”

A few online training options currently exist, including a program from NFPA on responding to incidents involving both ESS and solar panels, also known as photovoltaic panels. “The three-hour, self-paced module with engaging videos, animations, simulations, and review exercises provides basic knowledge of electrical theory, types of photovoltaic installations, and battery chemistries,” reads a description of the training, available at There is also a course from the UL Fire Safety Research Institute (FSRI), and educational websites like But experts say it’s hard to keep any of these resources current. “The tech is zooming ahead so fast that the ability of codes and standards and the ability of training to keep pace is limited,” Sullivan said.

Further complicating the ability to provide comprehensive and up-to-date training are the differences among energy storage systems. They can have different types of batteries or different configurations, said Paul Rogers, a retired New York City Fire Department (FDNY) lieutenant who in 2019 cofounded the Energy Storage Response Group (ESRG). The group advises fire departments internationally on creating site-specific emergency response plans for energy storage systems in their jurisdictions. “No two systems are the same,” he said, “so it’s hard for the fire service to understand them.”

Most of the time, however, ESS incidents can be tied together by the fact that they resemble hazardous materials incidents—they can produce toxic fumes and contaminated water runoff, and they pose longer-term risks than conventional fires. “This is the new hazmat,” Towski said.

“The challenges of decommissioning systems after a fire or other damaging event can’t be overstated,” Rogers said. “It’s not as simple as putting the fire out. We know these things have a tendency to reignite. There may be stranded [electrical] energy in the damaged batteries and how to best get rid of that is still unknown.”

A 30-minute training video released by FSRI, FDNY, and New York Metro Area utility company Con Edison in 2021 reiterates the risk of stranded energy in these systems. “The biggest problem we have with these battery systems is that retained energy,” Anthony Natale, a member of Con Edison’s emergency preparedness team, says in the video. Stranded energy remaining in damaged batteries after they’ve seemingly burned out or been drowned in water is the reason reignitions can occur hours or even days following an incident.

This video, released by the UL Fire Safety Research Institute, FDNY, and Con Edison last year, details how firefighters in New York City respond to incidents involving energy storage systems.  FIRE SAFETY RESEARCH INSTITUTE VIA YOUTUBE

From a training perspective, Sullivan believes treating ESS incidents like hazmat incidents would be one way to establish clear levels of expertise within the fire service, similar to those outlined in NFPA 470, Hazardous Materials/Weapons of Mass Destruction (WMD) Standard for Responders. According to that standard, firefighters can fall under varying levels of qualification, from the most basic level (“awareness”) to the most advanced (“hazardous materials technician”). A level known as “operations” sits in between the two.

“I know there is some support behind this approach,” Sullivan said. “The fire service is already familiar with the three levels of hazmat training, and it’s a great way to get everybody involved since you can train on the awareness level as part of a firefighter’s initial fire academy training.”

Establishing training or qualification levels along these lines could also help clarify which personnel need to be on the scene or contacted during incidents—something firefighters struggled with at the incident in Surprise, Arizona. “In Surprise, the first crews showed up not really aware of what they were dealing with,” Sullivan said. “They were initially called to respond to a brush fire. When they arrived on scene, it was instead this big electric utility–looking thing that was smoking. They didn’t know who to call. It took several people at the utility company to even figure out who to talk to.”

McCormack, the Boston chief, added that “the beauty of making ESS incidents hazmat incidents” is that the responsibility for cleanup falls on the owner of the ESS. “There are federal codes that dictate this,” he said, alluding to regulations imposed by organizations including the Environmental Protection Agency and Department of Transportation.

In some places, such as New York City, the hazmat/ESS connection has already been codified. According to FDNY code, “The removal of any stationary storage battery system experiencing abnormal temperatures or gas emission readings as a result of physical damage, exposure to fire, or other cause of failure, must be coordinated with the Hazardous Materials Unit of the Fire Department’s Bureau of Operations.”

Emergency response to any ESS incident in New York City also mirrors a hazmat response, FDNY Deputy Chief George Healy says in the training video released last year. “We’re going to have our hazmat resources responding,” he says. “We’re going to take our time to manage the incident appropriately. It will take a lot of time and a lot of resources to make sure it’s safely and properly managed and mitigated. The hallmark to our safety will be slow, deliberate decision making and taking action, when necessary, in consultation with other first responders and our partners at Con Edison or whatever utility [manages] the installation.”

Partnerships, regulation, & data

Partnerships between first responders and ESS companies or ESS site owners, like the one FDNY has forged with Con Edison, are another critical component of setting the fire service up for success in safely and effectively responding to ESS incidents. Observers say both sides can learn a lot from each another.

“When we first started seeing ESS come into the city, we asked these companies about fire and they said, ‘Well, they don’t catch on fire,’” Rogers said, remembering his time at FDNY several years ago. Of course, that isn’t true, and the fire service has helped ESS manufacturers, installers, and the companies that manage existing systems understand the fire risks of these systems and fire department response capabilities over time. At the same time, these companies have a role to play in providing technical assistance to firefighters during incidents involving energy storage systems.

Today, what Rogers described as “a very aggressive” approach to providing that kind of assistance exists in New York City, where in order to operate an ESS, the owner of the system needs to have the capability to have technical staff on the site of an ESS incident within two hours. Part of that staff’s job on the scene would be helping firefighters understand the data that’s being collected by the battery management system (BMS) in the ESS, which is a computer that monitors all sorts of data from inside the battery storage containers, such as heat signatures and gas concentrations.

“It’s important to get into that battery management system,” Natale, the Con Edison employee, says in the training video. “That’s going to give us good insight into what’s going on in the system without having to put members in harm’s way.”

Rogers said the BMS data could be “instrumental in helping the fire service make better decisions,” and he urged any department with an ESS already in or being planned for their jurisdiction to make sure they have access to this data or know how to connect with somebody who does.

Like Con Edison, Salt River Project (SRP), a large public utility company in Arizona, has been proactive about partnering with the fire service on ESS incident preparedness. “We believe that the safe deployment of energy storage requires a partnership with local first responders,” said Sharon Bonesteel, who manages the Building Energy Codes program at SRP. “We hold annual trainings at our substations, place our emergency response plans in the 911 system, and conduct pre-incident planning for all our ESS installations.”

This video, released by NFPA Journal in 2020, details how stranded energy can pose challenges for firefighters responding to electric vehicle crashes and fires. NFPA JOURNAL

Similar steps will be taken in Sanford, Maine, when the town sees its first ESS installed later this year. “The company working on the installation has been very willing to work with us,” said Patrick Cotter, the Sanford fire marshal. “Part of the site plan that’s been approved requires the company to do classroom and onsite training for all of our fire department staff.”

Before any of these partnerships can be made or data tapped into, though, fire departments must be apprised of projects to install ESS in their jurisdictions. The degree to which fire department involvement in the ESS permitting process seems to vary widely from jurisdiction to jurisdiction. “I don’t think anyone is even sure of who the authority having jurisdiction is in some cases,” said McCormack. “Is it the fire department? Is it the building department? Is it the state or the city?”

When a project to install an ESS in Chesapeake, Virginia, was proposed in 2020, the ESS company applying for the permit told the city it would work with the local fire department to ensure preparedness for emergencies, but members of the city’s planning board seemingly had no information verifying that was true when it came time to vote on the project. “The info we’ve been provided is limited,” one planning board member said, before voting to delay the approval process. “I wasn’t even aware of what kind of batteries were being used. I’m a firm believer in renewable energy, but right now, with the information I’ve got, I can’t make a good decision.” The project was eventually approved, but not before several months of delays and stipulations that an emergency response plan be written by the ESS company together with the Chesapeake Fire Department.


An AHJ’s Guide to Energy Storage System (ESS) Listings and Fire Propagation Testing
Monday, June 6, 9:15–10:15 a.m.
Adam Barowy and Laurie Florence, UL

Lithium-Ion Energy Storage: A Panel Discussion of Lessons Learned from the Surprise, Arizona, Incident
Monday, June 6, 10:30 a.m.–noon
Paul Hayes, American Fire Technologies

Identifying and Reducing Explosion Risks in Energy Storage Systems
Wednesday, June 8, 2–3 p.m.
Matthew Paiss, Pacific Northwest National Laboratory

Developing ESS Response Training—A Collaborative Approach
Wednesday, June 8, 3:15–4:15 p.m.
Chris Towski, Cambridge Fire Department; Marty McCormack, Boston Fire Department

Asked whether a database to track ESS installations across a specific city, region, or state would be useful to the Boston Fire Department or other departments in closing some of these regulatory gaps, McCormack answered with a resounding yes. “It would be great if we knew where these installations were located in the city, especially for state-owned properties,” he said. “It would be easy to manage the information that the state would provide us because we already have a database in place for when a building has some special construction feature, such as a truss roof.”

Towski agreed that such a database would be helpful for Cambridge firefighters. “Boy, would it be nice if there were a database of ESS locations that could also be linked in real time to the data coming from individual battery management systems to give the fire service a heads up on what they might be getting into,” he said. But he also raised an important question: Why single out ESS? “We don’t currently track the locations of generators or other traditional energy systems,” he said.

Already, tensions can emerge between the fire service and ESS companies. In a blog published last year, an attorney at the Boston-based law firm Foley Hoag wrote that “fire code provisions … can make permitting a battery storage component unnecessarily complex, drive up the project costs, and delay energization.” The blog was celebrating the news that the Massachusetts Fire Appeals Board had recently shot down a local fire chief’s opposition to a proposed ESS in his town. If ESS projects are placed under further scrutiny through inclusion in unique databases that other energy projects aren’t, that could cause tensions to rise.

“I know of a particular proposal for an ESS in the northern part of the state that was met with so much resistance that the energy company packed up and left,” Towski said. “I don’t want it to be like that, because we need these systems for the resiliency they provide to the power grid. But these companies have to play ball with us. They have to involve us so we can help make these systems safer.”

More widespread awareness and adoption of NFPA 855 is a good place to start when it comes to creating safer, AHJ-approved ESS installations. The document—which has a new edition coming out later this year (see “A Revamped ESS Standard” as part of this story)—outlines ESS design and installation provisions such as prohibiting the construction of systems on a combustible roof and ensuring responders can access ESS sites.

In many cases, McCormack said, site owners and ESS companies are open to amending design plans when presented with sections of NFPA 855 and reasons why a previous design idea may not be optimal for safety. “There was a hospital we worked with that wanted to put an ESS on the roof,” he said, “so we came back to them asking if there’s a reason it needs to be on the roof. They said no, so we asked if they could put it in a parking lot and that’s what they did. The last thing you want is a fire on the roof of a hospital.”

Cotter shared similar experiences from helping plan the Sanford, Maine, installation. “Even though NFPA 855 hasn’t been adopted in any way in the state, we used that document as a guide, and we’ll continue using it, and the ESS company was more than accepting of that,” he said.

So far, in Massachusetts, sections of NFPA 855 have only been incorporated into state guidance documents—in other words, they’re not enforceable. Other states have taken things a step further. Since 2019, for instance, the California Fire Code has included language from NFPA 855.

McCormack and Towski remain hopeful that as ESS becomes a more ubiquitous technology, fire safety will be on more people’s radars, and that will translate to more opportunities for responder training and stronger regulatory measures that allow for fire service input. “The good thing is word is spreading about ESS fire safety and about 855,” Towski said. “Some ESS companies are starting to look at that document and starting to play by those rules without us even having to tell them to.”

ANGELO VERZONI is associate editor of NFPA Journal. Top photograph: NFPA