Abstract
Battery energy storage systems (BESS) installed with lithium-ion batteries (LIBs) are increasingly being used for the storage of electric energy in buildings. LIBs in BESS installations represent a fire and explosion risk related to increased internal resistance upon ageing, which may lead to a significant increase in cell temperature, resulting in thermal runaway (TR) with the formation of toxic and flammable gases. This study investigates the handling of fire and explosion hazards associated with seven BESS installations in Norway. All BESS installations were in separate fire compartments. However, the fire resistance of the compartments, layout of the battery rooms, ventilation, fire detection and fire suppression systems all varied significantly. Only one BESS installation was fitted with gas detectors, and only two with explosion control systems. This implies a lack of sufficient safety barriers against the risk of accumulating flammable gases. In addition, the distance between individual units inside the compartments was not adequate, which is a safety problem identified from a hazard identification that was conducted. The hazard identification revealed that a fire in a battery module represents a critical hazardous event that might result in fire spread to other modules and units. A likely cause of these major differences in fire and explosion safety measures is that Norway operates with performance-based regulations, combined with the limited knowledge of fire and explosion hazards associated with the use of LIBs. This is exacerbated by a lack of consistency between Norwegian and international standards on fire and explosion safety measures for BESS installations in buildings.