Battery Storage Facilities

What is a battery energy storage system (BESS)? 

A battery energy storage system (BESS) is a structure that houses a large group of batteries designed to store electrical energy, typically sourced from renewable energy like solar or wind power. The stored energy is released back into the grid when needed, such as during peak demand periods or power outages, helping to prevent rolling outages. 

Safety Risks from BESS

Thermal runaway in battery energy storage systems (BESS) using lithium-ion batteries occurs when heat builds up in a battery faster than it can be dissipated. This can happen due to factors like internal short circuits, overcharging, or external temperature fluctuations. As the heat accumulates, the chemical reactions inside the battery accelerate uncontrollably, leading to a rapid release of energy and a significant rise in temperature. This process can cause the battery to overheat, potentially resulting in a fire, explosion, or other hazards.

To mitigate these risks, facilities are designed with safety systems such as temperature monitoring, fire suppression technologies, and advanced battery management systems (BMS) that help prevent or detect potential issues early on. These systems help ensure that any heat buildup is addressed before it can lead to catastrophic failure, thereby protecting both the facility and the surrounding community.

When thermal runaway happens, the battery cell experiences an unstable chemical reaction. As oxygen combines with the toxic, flammable gases released, it can cause the cell to catch fire, potentially triggering a chain reaction that ignites nearby cells as well.

If the pressure inside the cell becomes too high, it can rupture, releasing flammable gases and, in some cases, high-speed projectiles. These gases can mix with oxygen, creating an explosive risk.

Lithium-ion battery fires produce extreme heat, along with large amounts of gas and smoke. The gases emitted from energy storage systems are both highly flammable and toxic. The specific gases vary depending on the battery chemistry but generally include carbon monoxide, carbon dioxide, hydrogen, methane, ethane, and other hydrocarbons.

The only proven method to stop ongoing thermal runaway in a lithium-ion battery is using large amounts of water over an extended period. However, this process can lead to hazardous runoff, carrying toxic and dangerous substances.

Are You Prepared?

Before a BESS facility incident

• If you live or work near a BESS facility:
  • Build an Emergency Supply Kit with the addition of plastic sheeting, duct tape, and scissors.
  • Make a Family Emergency Plan, and remember to include emergency planning for your pets. 
  • Ensure you have signed up for emergency alerts. 
  • Know how to operate your home’s ventilation system.
  • Identify an above-ground shelter room with as few openings as possible.
  • Read more about sheltering in place.

During a BESS facility incident

• Listen to local radio or television stations for detailed information and follow instructions provided by emergency officials carefully.