(98b) Hazards of Battery Energy Storage Systems (BESS), Mitigation Strategies, Minimum Requirements, and Best Practices

In the last few years, there has been a steady increase in the quantity of lithium-ion utility-scale battery energy storage systems (BESS). Standards, codes, and test methods have been developed which address battery safety and are constantly improving as the industry gains more knowledge about BESS). These standards address minimum requirements for battery shipping, installation, commissioning, and operation. In addition to the minimum standards, there are recommended practices that enhance the safety of utility-scale energy storage installations. This paper will review the recommended practices, that through knowledge and experience with BESS, are being adopted by electric utilities. The focus is on fire, explosion, and toxic emission hazards of battery thermal runaway events and its mitigation. The paper will fill in the gaps between what the minimum requirements dictated by the codes and standards, what AHJs and insurance companies are asking for, and what utilities are comfortable with. Specific areas of discussion are thermal runaway, system deflagration and conflagration, spacing of BESS containers, facility siting, augmentation spaces, toxic and flammable gases, plume dispersion studies, water misting systems, fire protection systems, water strategy v’s no water strategy, battery chemistry selection, hazard mitigation analysis (HMA), detection redundancy, pre-startup safety review (PSSR), first responder training, AHJ/community engagement, personnel protective equipment (PPE), firewater runoff, re-ignition, stranded energy and decommissioning. The document is not a comprehensive analysis on every BESS safety topic. However, this is a recommended practices document that increases the technical acumen of environmental health and safety personnel and is intended to provide practical information to utilities and developers considering installing lithium-ion BESS.