Battery storage failure at SK Ulsan CLX site, Ulsan, South Korea
Jan 2022Published 11 Sept 2026Responsible editor: Chief Editor
- Where
- 10 MW, 50 MWh BESS in Nam-gu, Ulsan, South Korea
- What
- Failure event damaged about 1 percent of installed capacity
- Cause
- Not reported
- Outcome
- Damaged about 1 percent of installed capacity
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Companies named in the reporting of this entry (being named is not a finding of fault): SK E&S, SK On
What happened
On 12 January 2022, a 10 MW, 50 MWh battery energy storage system in Nam-gu, Ulsan, South Korea, using NMC cell chemistry and installed indoors for peak load reduction, experienced a failure event approximately two years after entering service. According to the EPRI BESS Failure Incident Database, the event damaged about 1 percent of the installed capacity. No cause, fire response, injury or evacuation information has been reported. Based on matching location and capacity, the site is inferred to be SK Ulsan CLX, operated, owned and with equipment manufactured by SK On, though this identification has not been directly confirmed by any incident report.
A 2018 news report describes a similarly sized 50MWh ESS installed at the SK Ulsan CLX complex by SK Innovation and SK E&S, but that article does not describe this incident.
Contributing factors
Not reported in available sources.
Lessons learned
- Indoor NMC battery systems need early detection systems because a failure can still damage capacity even two years after commissioning.
- Operators should confirm site identity from direct reports rather than matching capacity alone.
More lessons on detection and monitoring, from every incident on the register.
Not yet known
- Cause of the failure
- Equipment model and age
- Downtime and repair cost
- Fire response or evacuation details
This entry is updated when these are reported. Get an alert for the next one like it.
Standards referenced
EPRI
Other entries that name Ulsan
Published 2026-09-11. Written from public reporting. Descriptive, not investigative. See the data accuracy disclaimer.
