ESS Energy Storage Leading on Safety Background 2023

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Claims vs. Facts
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Energy Storage Leading on Safety
Background
Energy storage systems (ESS) are critical to a clean and efficient electric grid, storing clean energy and enabling its use when it is needed. Installation is accelerating rapidly—as of Q3 2023, there was seven times more utility-scale energy storage capacity operating than at the end of 2020. This growth is driving job creation, investment in American manufacturing, and is improving grid resilience and energy security.
However, because energy storage technologies are generally newer than most other types of grid infrastructure like substations and transformers, there are questions and claims related to the safety of a common battery energy storage technology, lithium- ion (Li-ion) batteries. All of these questions and claims can be addressed with facts. The industry continues to address these concerns to ensure community confidence in this increasingly essential electric grid infrastructure.
CLAIM: The incidence of battery fires is increasing. FACTS: Energy storage battery fires are decreasing as a
percentage of deployments.
• Between 2017 and 2022, U.S. energy storage deployments increased by more than 18 times, from 645 MWh to 12,191 MWh1, while worldwide safety events over the same period increased by a much smaller number, from two to 122.
• During this time, codes and standards regulating energy storage systems have rapidly evolved to better address safety concerns.
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CLAIM: Today’s larger battery systems use tens of thousands of cells, so fires are inevitable.
FACTS: Cell failure rates are extremely low, and safety features in today’s designs further reduce the probability of fires.
• One estimate from 2012 quotes a failure rate ranging from 1 in 10 million to 1 in 40 million cells3, and there are undoubtedly improvements from these levels.
• Lithium-ion batteries experience extremely low failure rates, as shown by electric vehicle data.
• Teslaalonesoldnearly900,000vehiclesinthefirsthalfof
20234. These sales of new vehicles represent around three- quarters of a billion cells, but safety events involving all EVs on the road globally, from all manufacturers, amounted to just a few dozen fires.
• Today’s energy storage systems (ESSs) predominantly use safer lithium-iron phosphate (LFP) chemistry, compared with the nickel-manganese-cobalt (NMC) technology found in EVs. • LFP cell failure results in less energy release and a lower
probability of fire.
• ESS designs incorporate features to avoid propagation of cell failure within the battery, contributing to improved safety.
1 US Energy Storage Monitor, Q1 2023 full report and 2022 Year in Review, Wood Mackenzie Power & Renewables/American Clean Power Association, https://www.woodmac.com/industry/power-and-renewables/us-energy-storage-monitor/
2 Electric Power Research Institute, BESS Failure Event Database, https://storagewiki.epri.com/index.php/BESS_Failure_Event_Database
3 D. Doughty, Vehicle Battery Safety Roadmap Guidance, National Renewable Energy Laboratory, October 2012, https://doi.org/10.2172/1055366.
4 EV sales: Hyundai overtakes GM, but Tesla’s U.S. dominance continues
Claims vs. Facts: Energy Storage Leading on Safety December 2023 cleanpower.org
Utility-scale battery energy storage is safe and highly regulated, growing safer as technology advances and as regulations adopt the most up-to-date safety standards.