October 7, 2025

Discover the best ways to install Battery Energy Storage Systems (BESS) to mitigate the risk of uncontrolled combustion.

What is BESS?

BESS are devices that enable energy generated from a variety of on-site technologies to be stored during off-peak hours and used to supplement energy during peak demands or outages. These devices are essential to microgrids, which were discussed in our last article “Microgrids: The Smart Power Solutions for a Resilient Energy Future.”

While this technology has incredible benefits, there are some hazards that users should be aware of and prepared for. Whenever a large amount of energy is stored in a relatively confined space, there is a risk of the energy escaping in an uncontrolled manner. This often results in fires or explosions.

Hazards & Failures

In pursuit of cleaner and more accessible energy generation, BESS have been installed globally at a high rate with energy storage capacities growing by nearly 200% since 2023. Due to this rapid deployment, assessment of the fire hazards associated with the installation has had to happen in real time. While a fire event resulting from using these systems is an uncommon occurrence, there have been some notable installations that resulted in flames or worse. Examples of these fire events happened at Arizona Public Service, Tesla in Victoria, Australia, and a private company in Seoul, South Korea.

Here is a deeper dive into the specific hazards that can lead to a fire event:

1. Thermal Runaway/Off Gassing

  • This is the rapid uncontrolled release of heat from a single battery cell that can result in a chain reaction. The compounded heat can cause the batteries to release highly flammable gases and serve as an ignition source. If the gases are not properly ventilated and continue to accumulate without being ignited, an explosion may occur.

2. Stranded Energy

  • This is when a battery cell is unable to safely discharge stored energy back into the user’s system as intended. The stored energy can unexpectedly release that energy, further damaging adjacent battery cells or potentially igniting released flammable gases.

3. External Abuse

  • This is any set of extreme external circumstances beyond the batteries design parameters that can result in the integrity and function of the battery failing. This includes extreme temperatures, overcharging, or physically damaging the battery.

Safety Considerations for BESS

In response to multiple failure events, people have globally started to investigate establishing safety considerations when it comes to the installation of BESS. Most notably, New York State convened an Interagency Fire Safety Working Group (FSWG) to improve the Fire Code and make recommendations for requirements addressing these safety concerns. These recommendations were produced with a focus on outdoor, grid scale systems and may be excessive for smaller applications.

The recommendations fall into three categories:

1. Fire Code Updates

  • This category includes modifying the language of the existing code to further expand on requirements. For instance, the FSWG recommends the installation of monitored Battery Management Systems (BMS) and video surveillance that collects data on the voltage, state of charge, gas detectors, and temperature of the battery cells. This allows potential hazards to be detected early and assists with post-event analysis should a fire event occur.

2. Fire Code Additions

  • This category includes supplemental sections influenced by tangential code references like NFPA 855, Standard for the Installation of Stationary Energy Storage Systems. For example, the FSWG recommends that the BMS references above be monitored from a central station that is directly connected to the local fire department for expeditious response. Furthermore, they recommend requiring a periodic special inspection to ensure compliance is maintained throughout the life of the system.

3. Additional Considerations

  • This category includes recommendations that may not be appropriate for the scope of the Fire Code by they are constructive for ensuring safe installations of BESS. The FSWG recommends establishing guidelines for design and intent of water as a suppression tool in BESS fires and installing firestops on all BESS enclosures. These recommendations aid in slowing down the impact of a fire event.

Suppression & Extinguishment

With all the safety considerations applied, there are still rare cases where a fire event occurs for one reason or another. In that case, how does a Fire Department contain and fully extinguish the fire?

In order to mitigate thermal runaway, water can be used to douse the exterior of the battery enclosure and absorb the heat. This is something that must still be done cautiously because if the water encounters a battery that has stranded energy, electrical shorting can occur. For direct contact with batteries, specialized agents work best in lieu of water. Each agent is unique in how they fight fires; some remove oxygen from the space, and some have a cooling effect to absorb heat.

Even with these resources, suppression and extinguishment is a long process that requires patience and expertise to ensure that reignition does not occur.

Let’s Stay Safe!

No matter the type of facility you own/operate, a BESS can be installed safely. However, there are several considerations to explore in order to understand the feasibility of a system. Each design will vary based on the needs of the facility, so it is imperative to consult with a professional first. Collado Engineering monitors the latest in fire safety technology and is familiar with the relevant regulations/incentives for your system. We are happy to advise on the next steps of the process!

By: Edbin Gonzalez Calderon