Lithium-ion BESS thermal event with flare-ups over several days
2024Published 17 Apr 2026Responsible editor: Chief Editor
- Where
- utility-scale battery energy storage facility in North America
- What
- thermal event with intermittent flare-ups for seven days
- Response
- coordination with site operators, fire services and environmental authorities; air quality monitoring
- Cause
- Not reported
- Outcome
- site declared secure after seven days
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What happened
In May 2024 a utility-scale battery energy storage facility in North America experienced a thermal event. The installation used nickel manganese cobalt (NMC) lithium-ion cells. After the initial event, intermittent flare-ups continued for approximately seven days before the site was declared secure. The response involved coordination between site operators, local fire services and environmental authorities, and air quality monitoring was carried out throughout the response period. Public reporting records that the site had experienced an earlier thermal event before this one. The account here is drawn from a publicly issued environmental agency case study on battery energy storage incident response.
Contributing factors
No root cause findings were available at the time of writing and none are reproduced here. Industry literature, rather than any finding specific to this site, notes that NMC lithium-ion chemistry has a higher thermal runaway propensity than lithium iron phosphate, and that high cell density in utility-scale installations can allow a thermal event to propagate from cell to cell if it is not contained.
Lessons learned
- NMC lithium-ion cells in a utility-scale BESS can produce flare-ups for days, so operators must plan for prolonged monitoring and exclusion zones after the first signs of thermal runaway.
- A prior thermal event at the same BESS site raises the chance of repeat failure, so response plans must record and brief staff on that history.
- NMC cells and high cell density increase propagation risk, so operators should verify that enclosure spacing and containment match the chosen chemistry in the safety case.
More lessons on detection and monitoring, spacing, layout and fire spread, from every incident on the register.
Not yet known
- Root cause of the thermal event
- Battery cell model and age
- Duration of site downtime after secure
- Cost of the incident and repairs
This entry is updated when these are reported. Get an alert for the next one like it.
Published 2026-04-17. Written from public reporting. Descriptive, not investigative. See the data accuracy disclaimer.
