Lithium Ion Battery Energy Storage Systems (BESS) Hazards

Why Discuss BESS Risks Now?

If you’ve been following the clean energy boom, you’ve probably noticed how quickly lithium ion battery energy storage systems (BESS) are popping up around the world. From suburban neighborhoods with home backup systems to massive utility-scale storage farms stabilizing the grid, BESS is everywhere.

But the catch here is that as installations mount, so do reports of fire, explosion, and toxic gas release. And while "hazard" could be read as sensationalistic, it has nothing to do with fear-mongering. Rather, it's a question of posing the right question: What is really occurring inside these storage boxes, and how can we improve their safety?

The Core Hazards of Lithium Ion BESS

Thermal Runaway — The Domino Effect

The biggest thug in this case is thermal runaway. It's as if lighting one domino on fire and watching them all fall. When a single cell overheats from a short circuit, an overcharge, or even from a manufacturing defect, it continues and continues to its neighbors unchecked. The result? A fire that feeds itself and is nearly impossible to extinguish.

• Fire and Explosion Risk: The heat will rupture cells open and force out flammable gases, a time bomb waiting to explode in an enclosed space.
• Toxic Gas Venting: Gases like hydrogen fluoride are not only flammable — they are poisonous if inhaled. Imagine firefighters walking into a cloud of poisonous chemicals that can't be seen.

Electrical Risks

These are high-voltage systems, often running in the hundreds or thousands of volts. Touch the wrong surface, and the result isn’t just a “zap” — it’s potentially lethal. Improper grounding, poor design, or maintenance shortcuts can make things worse.

Environmental and Mechanical Hazards

• Flooding or corrosive mists can damage wiring.
• Rats chewing through insulation? Not uncommon.
• Even seismic shocks or forklift impacts during installation are sufficient to shatter cells, initiating subsequent failures.

So are they just "worst-case scenarios," or do they ever actually happen?

Real-Life BESS Fire Incidents

In spite of more stringent codes and more sophisticated system design, the past three years saw some high-profile BESS fire incidents that continue to shape safety standards:

• Moss Landing, Monterey County, California — Jan 2025
  A large thermal incident at Vistra's Moss Landing facility—one of the world's largest storage plants—led to evacuations and road closures. Follow-up studies detected heavy-metal pollution in local marsh soils, showing big wildfires can leave lasting environmental imprints and require concerted public health monitoring.
• Gateway Energy Storage (San Diego), California — May 2024
  Several days of flare-ups stretched firefighting capabilities to the limit, demonstrating how hard it is to suppress lithium-ion thermal runaway once propagation occurs. Highly specialized response protocols and contingency planning over longer durations were identified as definite requirements.
• Escondido, San Diego County, California — Sept 2024
  Industry reports cited inadequate venting and breached system-level fire barriers as sources of spread. The incident is cited in permitting arguments today as a reminder that lessons from safety during deployment must be considered when municipal planning is done.
• Valley Center, San Diego County, California — Sept 2023
  Even for a fire that was limited to one containerized unit, massive emergency response was required, evidence of the risk of locating storage near residential or sensitive land use.
• Warwick, New York — June 2023
  Two commercial BESS units were involved in a fire, producing smoke that required local school evacuations. No one was injured, but community disruption was significant—a typical example of the "social cost" of BESS fire incidents.
• Fredericktown, Missouri — Oct 2024 (Battery Recycling Facility)
  A lithium-ion recycling facility fire/explosion demonstrated that dangers range across the entire life cycle of the battery—manufacturing, storage, transport, and end-of-life processing—not just grid-connected BESS sites.

Why is Lithium Ion BESS Especially Susceptible?

That's the paradox: lithium-ion batteries are popular for their energy density, fast response, and low cost. But those same attributes that appreciate them make them dangerous.

• Narrow temperature ranges: Cells have an optimal temperature between 15°C and 35°C. Wander outside those boundaries, and the curve of risk steepens rapidly.
• Aging factor: As batteries become older, they emit more heat when under stress, generating a higher probability of thermal events toward the end of their lifespan.
• Electrolyte chemistry: The same fluid that carries ions is highly combustible — a design feature that engineers still struggle with.

Mitigation Measures: Can We Tame the Risk?

No technology is ever risk-free, but BESS risks can be kept low through good planning and engineering.

• Industry Codes: NFPA 855 and the International Fire Code require hazard mitigation analysis (HMA) of large installations.
• Battery Management Systems (BMS): Treat them as the "brains" of BESS, monitoring temperature, voltage, and current to prevent runaway.
• Early Fire Detection (EFD): Advanced sensors can identify chemical vapors ahead of fire.
• Thermal Barriers: Insulation placed in between cells prevents the passage of heat.
• Explosion Venting: Properly designed tanks can prevent pressure buildup leading to fatal explosions.

The question is: Will corporations always invest in these measures, or cut corners to save money?

Who Should Care About BESS Hazards?

• Utilities and Grid Operators: A 100MW fire in a facility can take down grid stability for a thousand homes.
• Businesses: Warehouses or factories using behind-the-meter storage must weigh insurance and liability risks.
• First Responders: Firefighters may enter hazardous or explosive environments untrained, with no knowledge of the dangers.
• Homeowners: BESS for residences are small, but poor installation or imitation batteries present some very real threats.

Industry Trends and the Road Ahead

There's better news. The energy storage sector is evolving rapidly:

• Next-Gen Chemistries: Solid-state batteries should be less flammable but, in the meantime, are not yet mainstream.
• AI-Watched Viewing: Predictive analytics are able to spot failure patterns years before they become crises.
• Insurance Squeeze: Insurers are nudging operators towards stronger compliance with fire codes, pretty much indirectly forcing operators to become safer.

And here's the question — will BESS ever be regulated to the standard of "fire safety" that natural gas or nuclear facilities are? Or will lithium-ion forever be sporting that specter of danger?

A Quick Anecdote

At a conference last year, one presenter quipped: "The safest battery is the one you never charge." Funny, sure, but it's true — energy density = risk density. You can't have one without some of the other.

Final Reflection

Lithium-ion battery energy storage systems have opened a cleaner, more sustainable grid, but their risks are all too real. Fires and explosions, toxic gas leaks, and electrical shock aren't possibilities—they're realities, and they will keep on happening unless prevention is an absolute requirement of the design and operation.