Megapack fire at PG&E Elkhorn Battery, Moss Landing, California
2022Published 1 May 2026Responsible editor: Chief Editor
- Where
- Elkhorn Battery Energy Storage System, Moss Landing, California, United States
- Operator
- Pacific Gas and Electric (PG&E)
- What
- Fire in a single Tesla Megapack battery enclosure
- Injuries
- None reported
- Cause
- Water entered due to improperly installed vent shield panels
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Companies named in the reporting of this entry (being named is not a finding of fault): Pacific Gas and Electric, Tesla, Vistra Energy
What happened
In September 2022, a fire occurred in a single Tesla Megapack battery enclosure at the Elkhorn Battery Energy Storage System in Moss Landing, California, United States, owned and operated by Pacific Gas and Electric (PG&E). The site held 256 Megapack units. The fire started in the early hours of the morning. Safety controls automatically disconnected the facility from the grid, as designed. Shelter in place advice was issued to nearby residents while the local fire service attended.
The fire was brought under control later the same day and remained confined to the single enclosure, without spreading to neighbouring units. No injuries were reported and there was no interruption to electricity supply to customers. The Elkhorn facility is separate from Vistra Energy's neighbouring Moss Landing Energy Storage Facility.
Contributing factors
According to the findings published by PG&E, water entered the affected Megapack because its deflagration vent shield panels had been installed improperly, and that water intrusion led to the thermal event. The investigation found that 88 Megapacks on the site had experienced water intrusion from improperly installed vent shields. All 88 were inspected, damaged parts were replaced and the units were re-tested. PG&E and Tesla reported corrective actions covering the installation of the equipment, monitoring processes and additional automated features.
Lessons learned
- Check all vent shield panels on Megapack units after installation, because improper fit allowed water to enter and cause a thermal event.
- Test that automatic grid disconnection works on safety trips for BESS sites, as it operated here and limited the outcome.
- Inspect all identical units when water intrusion is found in one Megapack, since 88 units on site had the same defect.
More lessons on maintenance, inspection and ageing assets, from every incident on the register.
Not yet known
- Exact date in September 2022
- Cost of inspection and repairs
- Which monitoring changes were added
This entry is updated when these are reported. Get an alert for the next one like it.
Source
Site page: Elkhorn Battery Energy Storage System (status, dates and other incidents)
Other entries that name Elkhorn
Other entries that name Moss Landing
- New fire smoulders at Vistra Moss Landing battery site during cleanup
- Major fire at Moss Landing Energy Storage Facility, California, multi-day incident
- Clamp failure and coolant leak found during Moss Landing battery restart testing
- Battery storage fire reignites at Vistra's Moss Landing facility
- Water based suppression system leak causes battery shorting at Moss Landing Phase II
Published 2026-05-01. Written from public reporting. Descriptive, not investigative. See the data accuracy disclaimer.
