Tesla Megapack Battery Ignites At Substation After Less Than 6 Months

A Tesla Megapack battery at a California substation caught fire early yesterday morning, prompting a shelter-in-place order and multiple road closures around the Moss Landing area of Monterey Bay. 

According to the Monterey County Weekly, the North Monterey County Fire Department received a call about a burning Tesla Megapack at the Elkhorn Battery Storage facility, a 182.5 MW Pacific Gas and Electric (PG&E) facility co-managed by Tesla and in operation since April of this year.

According to fire chief Joel Mendoza, the battery burned quickly and cleanly, a rarity for such fires. "The thing about these batteries is they burn for days, sometimes. In this particular case it burned rather quickly, in six hours or so," Mendoza said. "We don't have any flame coming out of it. We're going to continue to see smoke; it's white smoke, not black dirty smoke."

As of 10 p.m. local time yesterday, roughly 20 hours after the fire was reported, Monterey County said the fire was fully controlled, but said it may continue to emit smoke for several days. 

Per CNBC, firefighters on the scene allowed the battery to burn out, as is standard practice for lithium-ion fires. Firefighters planned to remain on scene overnight to ensure the system didn't re-ignite. 

Tesla hasn't responded to emails requesting additional details. PG&E said it had no comment.

Lithium-ion fires frequent at large battery facilities

As the US shifts to distributed, renewable energy generation, facilities like the Elkhorn Battery storage facility will become increasingly important parts of the grid, as they're able to retain energy during surplus production periods so they can release it later, when renewables are underproducing. 

Unfortunately, large lithium-ion battery facilities like Elkhorn, which consists of 256 shipping container-sized Tesla Megapack batteries, have proven to be fire hazards – even at the same Moss Landing substation. 

Texas-based Vistra also installed a battery storage facility at Moss Landing that Monterey County Weekly describes as the largest in the world. Unfortunately, it too has been plagued by fires – two of them – and was shut down for months, only re-entering service in July. 

Tesla has been involved in other li-ion fires, with its Australian "Big Battery" bursting into flame last year and burning for four days. Li-ion batteries can also ignite weeks after damage, as was the case with a Tesla vehicle totaled in an accident. 

In South Korea, where battery energy storage systems (BESS) have been deployed widely, there were 23 BESS fires between 2017 and 2019 resulting in $32 million in losses. Investigators in Korea said lack of electric shock protection, inadequate operating environment management and faulty installations were to blame, along with BESS integrations with other energy management software, which they said "can result in conditions that lead to fire." 

Despite known problems, lithium-ion continues to be the standard for rechargeable batteries. Researchers have discovered new cathode and anode materials that are safer than li-ion, but no big breakthroughs have been made recently that could challenge its dominance – a potentially serious problem as giant BESSes get built in more locations. ®