What’s a battery energy storage system?
A battery energy storage system (BESS) stores energy in rechargeable batteries. A system typically has battery cells, modules, racks, inverters, and control systems.
BESS are installed for many reasons, like to support the electrical grid, integrate renewable energy, or provide backup power to critical infrastructure.
Are they safe?
BESS installations must comply with strict safety standards including NFPA 70 (National Electrical Code) and NFPA 855 (Standard for the Installation of Stationary Energy Storage Systems). These standards minimize risks by addressing fire safety, ventilation, and emergency planning. Less than 2% of installations have a malfunction.
How does NFPA 855 apply to Texas BESS installations?
In areas where SFMO has jurisdiction, the provisions of NFPA 855 (2020 edition) are applicable and enforceable for BESS that exceed the thresholds in Table 1.3 of NFPA 855. The model codes adopted by other jurisdictions typically reflect the same NFPA 855 standard and requirements.
What kind of emergency planning is required for a BESS?
Each BESS facility operator must develop an emergency operations plan. The plan must include safe shutdown procedures and emergency response considerations, like firefighting and annual staff training.
How does NFPA 855 address thermal runaway?
The standard requires thermal runaway protection for electrochemical BESS. This includes measures to prevent, detect, and minimize the impact of thermal runaway events in BESS.
Does NFPA 855 address different BESS technologies?
NFPA 855 has specific chapters for different technology classes. For example, it has separate chapters for electrochemical (battery) systems or capacitor energy storage systems. Each chapter addresses safety considerations.
Does NFPA 855 require inspection and maintenance?
NFPA 855 mandates regular BESS inspections and maintenance. This includes visual inspections, functional tests, and documenting maintenance activities. The frequency and scope of inspections depends on the system type and size.
Does NFPA 855 require fire detection or fire suppression?
NFPA 855 requires early warning fire detection systems and fire suppression systems for energy storage systems, depending on the system size and type. Typical detection systems include smoke detection, gas detection, and temperature monitoring systems. Fire suppression systems can be water-based fire sprinklers or another engineered fire suppression system.
Where can I learn more about the 2023 edition of NFPA 855?
The 2020 edition of NFPA 855, the edition referenced in the SFMO’s current fire code, was the first edition with information about BESS. The 2023 edition of NFPA 855 includes all BESS and lithium battery storage.
The use of NFPA 855 to a BESS installation is mandatory or voluntary, depending on the facility’s location.
In areas where the SFMO has jurisdiction, use is mandatory. The standard incorporates exemptions to installations under the exclusive control of utilities.
In response to data gathered from BESS fire incidents, NFPA 855 added or revised many requirements. This includes:
- Fire detection and suppression.
- Explosion control.
- Exhaust ventilation.
- Gas detection.
- Thermal runaway.
NFPA 855 also clarified requirements for fire and explosion testing (formally known as large-scale fire testing).
To make electrochemical BESS requirements easier to find, the 2023 NFPA 855 combined Chapters 4 and 10 into one chapter (Chapter 9).
Annex B provides more guidance about the hazards of additional battery types. Annex G was added as a guide for suppression and safety of lithium-ion BESS. These annexes are applicable for cities and counties under the SFMO’s jurisdiction.