BATTERY ENERGY STORAGE TECHNOLOGIES AND SAFETY STANDARDS ARE CONSTANTLY IMPROVING Fires that have occurred at lithium-ion battery energy storage system (BESS) facilities in recent years have raised concerns about the safety of BESS projects among decision-makers, the news media, and community members. This fact sheet provides an overview of the key innovations that make today’s battery storage projects less susceptible to fire and that greatly reduce the extent of fires if they do occur.
Evolving Industry Safety Standards
In response to a request from CESA, the National Fire Protection Association (NFPA) published its first BESS standard, NFPA 855, in 2020. The NFPA 855 standard, which is largely adopted in the California Fire Code, is updated every three years. Recently developed facilities have followed either the 2020 standard or the newer NFPA 855 2023 standard. These standards, and improvements in BESS technology and fire detection and suppression systems, have substantially reduced the likelihood of future incidents.
Today all new battery models undergo a testing and certification process that ensures that a failure will not cascade beyond one single battery, even when deliberately set on fire. The UL9540a standard defines Industry innovations have significantly improved BESS technology and safety standards.
the testing protocol for individual and packaged battery products (cells, modules, and whole battery storage units) and Large-Scale Fire Testing (LSFT) protocols for multiple units in close proximity. Earlier generations of BESS products were not required to demonstrate that fires in one battery would not propagate to adjacent units as is standard today.
Competing BESS Project Layout Approaches : Buildings vs Containers
In the 2010s, as the lithium-ion battery energy storage industry was emerging, project developers used one of two competing approaches to developing large-scale BESS facilities for wholesale electricity market participation. The first involved placing racks of energy storage modules in large, warehouse-like buildings. The second involved arranging standardized enclosures, which resemble shipping containers, in outdoor locations. In recent years, the energy storage industry has shifted decisively toward containerized systems. This transition was driven by the cost and manufacturing quality control advantages of enclosure-based BESS. Although lithium-ion building-based systems can be designed to limit the risk of propagation from one rack to another, containerized configurations inherently limit the scope of BESS incidents, as discussed below.
Less than 10% of the approximately 200 utility-scale facilities in California are building-based. CALIFORNIA ENERGY STORAGE ALLIANCE