Batteries designed for power system support are sometimes housed in distinct enclosures, and a single site can hold dozens or hundreds of them. Some arrays are in new facilities, while others occupy structures from past decades. This variation in physical environment leads to potential risks if older complexes lack current standards.
The American Clean Power Association (ACPA) notes that keeping projects safe requires coordination among operators, regulators, and public officials: “The battery energy storage industry has developed a comprehensive and proactive approach to ensuring safety across the United States.”
Prior incidents involving thermal runaway continue to guide modern engineering. Some events in the past decade caused limited contamination, which was addressed by specialized teams. ACPA references an assessment by the Fire and Risk Alliance, explaining that no serious community-level remediation was required in those historical cases.
Designers have integrated advanced sensors and automated controls, and many systems installed over the last few years follow strict checks from recognized institutions. The tests examine how battery modules react under heat, physical damage, and irregular charging.
Local departments often outline concerns about unfamiliar technology or potential events that can produce smoke or flame. These concerns remain valid. For that reason, UL (Underwriters Laboratories) and the National Fire Protection Association (NFPA) have created guidelines that inform each stage of project design and upkeep. ACPA’s research suggests that consistent adoption of these guidelines helps assure a stable operating environment, though there is an ongoing need for training programs that meet local requirements.
A widely referenced event took place at the Moss Landing facility. Investigations concluded that this was linked to an older turbine hall environment from the 1950s. ACPA’s review underlined the rarity of that scenario by emphasizing the significance of modern engineering for containment: “Many documented BESS fires involved early-generation systems that predate modern safety standards. The implementation of robust national codes and advancements in ESS design have significantly improved fire safety and reduced risks.”
Technologies from various manufacturers have been scrutinized. Data compiled by safety experts show that while certain older sites carry heightened risk, updated systems reflect modern engineering strategies. Some professionals emphasize that a mismatch between codes across different municipalities slows the transition toward uniform permitting.
ACPA points out that multiple states have begun adopting NFPA 855 requirements to mitigate potential hazards. That approach encourages consistent levels of equipment spacing, emergency response planning, and installation testing.
Three standards appear regularly in ACPA’s publications. UL 1973 focuses on battery cells, modules, and packs by addressing resistance to mechanical shock, temperature extremes, and electrical misuse. UL 9540 goes beyond component-level checks, covering system integration. ACPA’s text mentions that project developers rely on repeated testing to confirm reliability: “Battery energy storage technologies are designed to meet and exceed qualification standards. These systems are tested and vetted, certified, and ultimately built to comply with the nation’s leading safety standard.”
UL 9540A is another testing procedure. It explores how a thermal event might propagate from a single cell to a large container, which is especially helpful for site designers. By applying different forms of ventilation or fire-suppression systems, engineers can contain the threat. ACPA notes that when these tests become part of mandatory code, local authorities gain reassurance that large installations meet recognized benchmarks for hazard prevention.
NFPA 855, issued by the National Fire Protection Association, is the central reference for stationary energy storage safety rules in the United States. It outlines steps for design, installation, commissioning, operation, maintenance, and eventual decommissioning, while covering elements like separation distances between battery units and integration of advanced firefighting equipment on site.
ACPA cites a fire official, Kara Gerczynski, who explains that local regulations must adopt and enforce these codes in full: “Regulators and policymakers should be aware of required codes and standards, because those must be incorporated into local regulations. NFPA 855 requires all battery energy storage systems be listed to UL 9540, a standard that incorporates the entire system: the enclosure, the communications, the HVAC…a whole systems approach.”
Homer Electric in Soldotna, Alaska, installed a 46-megawatt battery complex using Tesla Megapacks. That region’s rural geography demands stable power options, especially when natural conditions disrupt conventional supply. The array’s design meets UL standards, with multiple containment processes in case of emergency. ACPA mentions that no major fire or thermal event has been reported there, reflecting the value of early hazard analysis.
Plus Power’s Kapolei facility in Hawai‘I works with local utilities to address peaks in electricity consumption. The design uses distributed containers with built-in fire detection, and site personnel receive training on preventative maintenance schedules.
According to ACPA, the aim is to keep large deployments safe while addressing capacity constraints that can appear during windy or sunny days. On a smaller scale, business operators in other states have installed battery storage for microgrids, especially in areas prone to storms.
ACPA notes that existing sites constructed before NFPA 855 was published may not align with these rigorous provisions. To address that gap, various state agencies collaborate with local fire districts and engineering teams to evaluate older infrastructure. Some might require partial upgrades, such as installing barriers, adding advanced monitoring devices, or strengthening ventilation. The aim is to reduce risk, even if the facility itself dates back to a time when fewer guidelines existed.
Local and county fire departments benefit when site managers supply detailed documentation of battery capacity, layout, and extinguishing protocols. Some equipment needs specific strategies if an internal fault arises, which differs from how firefighters handle traditional sources of ignition. This is another reason why ACPA’s resources mention annual or periodic training sessions. Those sessions cover detection sensors, enclosure design, and best methods to contain a problem.
Most major manufacturers also distribute guidelines that fire officials can reference on arrival. For example, enclosures that run advanced cooling or ventilation devices might have external indicators, so personnel can identify the affected compartments without stepping too close.
ACPA explains that NFPA 855 calls for multiple submittals, including a hazard mitigation analysis and an emergency response plan. Having those items on record means local officials can review important data before any unusual event emerges.
A combination of national and state-level policy decisions shapes how swiftly these codes become universal. Some states have adopted NFPA 855 in full. Others have integrated selective sections or remain in the process of approving the text.
ACPA and its partner organizations emphasize uniform enforcement, noting the importance of a consistent approach: “In addition to requiring tested and certified batteries and equipment, NFPA 855 includes requirements for metrics such as maximum energy and spacing between units and lists several submittals that must be made to the regulating governmental entity, including a hazard mitigation analysis (HMA), an emergency response plan (ERP), and details of all the safety features in the system.”
No single fix solves every scenario. Sites placed in older buildings might need structural adjustments, while projects in rural areas might require specialized approaches for harsh conditions. ACPA encourages a continued exchange between developers and local agencies. Joint work extends to the planning stage, where municipal officials often examine historical data on battery technology in their region and consult with engineers or independent safety experts.
Although battery hazards differ from those linked with large transformer stations or gas-fired turbines, thorough due diligence remains wise. This variety of perspectives allows a clear review of site conditions, planned capacity, and any likely hazards.
Energy storage, centered on battery arrays, has shown its potential to stabilize power supplies in places that experience surges or shortfalls. ACPA’s findings demonstrate that recognized standards from UL and NFPA have reduced risks related to fire events. Modern design methods enforce separation distances between battery units, robust enclosures, and integrated emergency response plans. They also ensure older facilities can upgrade if needed.
Local fire departments, state-level policymakers, and BESS developers continue to share insights on prevention strategies. This builds trust among communities that have reservations about new energy projects. Inspections are generally requested, especially for systems commissioned long ago.
Ongoing hazard assessments help confirm that large-scale batteries remain safe during operation. Multiple states have integrated NFPA 855 adoption into permitting steps, and others are preparing to do the same, guided by ACPA and related groups.
According to the American Clean Power Association, uniform rules remain one of the most effective ways to avoid problems stemming from conflicting local codes. Documents such as UL 9540A test whether an event in one module can spread to adjacent racks, which is especially important for multi-megawatt projects. Local training for officials has boosted readiness among first responders, and clarity about site layout shortens response times.
Engineers suggest that future projects stay aligned with evolving safety procedures. Battery chemistries may shift, with new options emerging, so updates to UL or NFPA documents will likely address any distinct hazards. ACPA points to the importance of codes that keep pace with these changes. Developers who plan large installations need to monitor code revisions, while authorities can watch for any signs of structural or equipment aging.
These approaches appear to be firmly established. Many of the practices highlighted by ACPA involve thorough planning, testing, and review. They help protect worker health and environmental conditions around each site.
A standard set of checks remains central for ensuring BESS deployments can deliver energy security without unexpected incidents. Adherence to recognized standards has already lowered incident rates, and that trend may continue as consistent code language and enforcement spread across regions.
