Tesla Megapack battery caught fire at PG&E substation in California 

Key Points

• A Tesla Megapack caught fire at a PG&E energy storage facility in Monterey, California on Tuesday.
• The fire caused road closures and shelter-in-place orders for residents nearby.
• Richard Stedman, an air pollution control officer for the Monterey Bay Air Resources District (MBARD) said in general lithium ion battery fires can emit toxic constituents like hydrochloric and hydrofluoric acid.

At least one Tesla Megapack caught fire early Tuesday morning at the energy storage facility operated by utility PG&E in Monterey, California.

As of late Tuesday morning, there were no power outages for PG&E customers, nor any injuries to on-site personnel due to the fire, according to PG&E spokesperson Jeff Smith. The California utility became aware of the fire at 1:30 a.m. on September 20, 2022, Smith said in an e-mail.

PG&E had commissioned the 182.5-megawatt (MW) Tesla Megapack system, known as the Elkhorn Battery at Moss Landing, in April this year.

Gigantic batteries like the Megapack, as well as those manufactured by ABB and Northvolt, enable grid operators to move extra capacity between counties or states, and ensure that power from intermittent sources can be stored and used when demand is higher, or when there are unplanned outages in a transmission network.

The fires in the energy storage systems at Moss Landing are reminiscent of incidents involving Tesla Megapacks in Australia. They also underscore the challenges of adopting new technology to improve the efficiency of the power grid, and to make greater use of electricity from intermittent, renewable resources like wind and solar.

There are two distinct energy storage projects at Moss Landing in Monterey. One is operated by PG&E and the other by Texas-based Vistra. On Tuesday, a spokesperson for Vistra told CNBC their facility was not impacted by this event. However, the Vistra side of Moss Landing has experienced two overheating incidents in the past.

California Highway Patrol closed a section of Highway 1 and redirected traffic away from the facility for hours following the fire.

A fire captain with North Monterey County Fire, John Hasslinger, told CNBC late Tuesday that two companies and four fire engines responded to the incident starting around 1:40 a.m.

The fire fighters used hydrants and water supply installed at the facility, and worked to prevent flames from spreading to adjoining batteries and structures in the larger system. By around 11:00 a.m. local time, fire fighters shut the water off but some were staying on location overnight to ensure that the system did not re-ignite.

“We let the initial Megapack burn out,” he explained as per protocols recommended by PG&E and Tesla to the fire department. “It’s too early to know what was the cause of the fire,” he added, but an investigation will follow in coming weeks.

Some residents near the Elkhorn Battery substation at Moss Landing were advised to shelter in place, keeping windows and ventilation systems closed, due to emissions after the fire. That advisory was still in place late Tuesday.

According to Richard Stedman, an air pollution control officer for the Monterey Bay Air Resources District (MBARD), lithium ion battery fires can emit toxic constituents, including hydrochloric and hydrofluoric acid. MBARD did not have any immediate data about air quality impacts from the Elkhorn Battery fire, he said, but will work with local authorities to study the issue after the fire has been fully extinguished.

PG&E’s Jeff Smith noted, “Safety systems at the facility worked as designed when the issue was detected, and automatically disconnected the battery storage facility from the electrical grid.”