Fire at Moss Landing Energy Storage Facility: What we know so far

On the afternoon of 16 January 2025, a fire broke out at Moss Landing Energy Storage Facility in Monterey County, California, US, prompting the evacuation of 1,200 to 1,500 local residents.

According to a press conference the following day by Monterey County authorities, a Level 2 activation of the County’s Emergency Operations Center (EOC) was enacted shortly after notification of the fire from nearby North County Fire Protection District.

Level 2 is the second highest level of response, and Monterey County communications officer Nick Pasculi said the EOC was then “fully staffed with county staff and partner agencies from around the county.”  

No injuries or fatalities have been reported, and Environmental Protection Agency (EPA) air quality monitoring so far has not shown sufficient release of hydrogen fluoride gas or particulate matter to cause risk to the public.

According to project owner Vistra Energy, active flames were no longer observed after the second day of the fire, but some smouldering was still being seen on 22 January, when the company last updated its webpage dedicated to the incident.

Evacuation orders were eventually lifted at 6pm on 17 January, and nearby road closures began to be lifted, while air quality monitoring is ongoing.

The incident has caused major concern for local authorities, including Monterey County’s Board of Supervisors.

County Supervisor Glen Church said it could “best be described as a worst-case scenario of a disaster that’s happened here,” adding that it was a “wake-up call for this industry.”

“If we’re going to be moving ahead with sustainable energy, we need to have safe battery systems in place,” Church said at the county’s 17 January press conference.

“There are a lot of questions from the residents in my district and the communities surrounding here, and they want to know why this happened. They want to know how it happened and what can be done to prevent it [from happening] in the future.”  

California State Assembly member for the 30th district Dawn Addis attended the site and yesterday livestreamed a press conference from Moss Landing introducing new proposed legislation, the Battery Energy Safety & Accountability Act.

Nick Warner, principal at energy storage fire safety specialist group Energy Safety Response Group (ESRG), told Energy-Storage.news in an interview that the incident is “tragic for the industry,” given its possible knock-on effects in terms of public acceptance of battery storage.

“It’s positive in that there doesn’t appear to have been any injuries,” Warner said, noting that the local fire department and other responders “did everything they needed to do to keep the keep themselves in the community safe, and by that account, they were successful.”

With investigations set to get underway, this site will not engage with speculation as to the root cause of the fire or its possible impacts on the wider industry. With that said, here’s what we know so far:  

What is Moss Landing Energy Storage Facility?

The large-scale standalone lithium-ion (Li-ion) battery energy storage system (BESS) project was the biggest in the world when its first 300MW/1,200MWh phase was completed and brought into commercial operation in December 2020.

The facility was expanded to 750MW/3,000MWh through two subsequent phases, with the most recent 350MW/1,400MWh installation completed in 2023, after the addition of the 100MW/400MWh Phase 2 in 2021.

Its owner is Texas-headquartered power producer Vistra Energy, and its offtaker is California investor-owned utility (IOU) Pacific Gas & Electric (PG&E) through resource adequacy (RA) contracts.

Moss Landing is an unincorporated community and census-designated place in Monterey County, California.

The site itself is the home of the Moss Landing Power Plant. Most of that thermal generation facility has been decommissioned, with one unit left in operation comprising two combined cycle gas turbines (CCGT), also owned by Vistra Energy, the owner of the BESS project.

Not only did Moss Landing, therefore, have the crucial advantage for site selection in having an existing grid connection that could be used and land on which to deploy battery storage systems; in this case, existing buildings which once housed turbines were repurposed for MOSS300, the first 300MW phase of the BESS project.

It is Phase 1, the battery-within-a-building, that has burned down. According to Vistra representatives, neither Phase 2 or Phase 3, nor the legacy CCGT plant were caught up in the fire.

Expert view

Phase 1 was equipped with nickel manganese cobalt (NMC) chemistry batteries provided by LG Energy Solution (LG ES) and mounted in the LG ES’s TR1300 Transportable Rack.

Unlike subsequent phases, the first 300MW system was put inside repurposed turbine halls formerly used by the Moss Landing Power Plant.

“That project—MOSS300—is incredibly unique globally, in that while the concept of dedicated use buildings is one that’s been talked about quite a bit and even executed, it’s rare that you see a dedicated use building that was repurposed from something else,” ESRG’s Nick Warner told Energy-Storage.news.

“The overall construction of MOSS300 is not like any other energy storage project, even other dedicated use [building] projects.”

Warner said that it is perhaps the most important lesson for the industry to learn that what happened last week at Moss Landing is “not indicative of what can or will happen at any other storage project.”

Last September, another BESS project in California that formerly held the title of biggest in the world, the 250MW Gateway project in Otay Mesa, also experienced a fire.

Warner noted that while Gateway too was a battery-in-a-building project, in that case, the building was purpose-built and included fire barriers, so while the fire did burn for four or five days, “only a small fraction of the building was compromised” and the rest of the battery storage system was returned into action just a few days after that incident.

Systems built before California fire codes, industry switch to LFP cells  

ESRG’s Nick Warner said that both MOSS300 and Gateway were built before California fire codes were updated to encompass large-scale battery storage and today’s product standards and certifications were in place for BESS equipment and installation.

“I think the main takeaway here is that while we should learn the lessons we can learn, I think it’s such a unique case that it’s not going to have a big impact on how we’re doing energy storage otherwise because best practice and codes have evolved so far from there, we would never do something like MOSS300 again anyway.”

Others have commented that the industry today has already largely moved away from NMC chemistry batteries to lithium iron phosphate (LFP) for stationary BESS applications.

While LFP, like NMC, can go into thermal runaway, it does have a higher thermal runaway onset temperature, Drew Leibowitz, managing director at BESS consultancy Powerswitch, commented on business networking site LinkedIn. LFP now accounts for more than 80% of battery storage projects, Leibowitz wrote.

“Indoor BESS projects are rarely built today, partially because of the fear that fire can spread throughout the system unchecked. Instead, most new installations are outdoor, pad-mounted systems which make fires less likely to spread,” Leibowitz also wrote.  

Marek Kubik, director of energy storage for Saudi Arabia’s NEOM project and a former market director at BESS system integrator Fluence, commented on the fast evolution of design standards that have occurred even since MOSS300 was commissioned.

Posting to LinkedIn Kubik noted that there is a greater emphasis today on UL9540A unit-level thermal runaway propagation testing and much more comprehensive treatment of storage in the National Fire Protection Association (NFPA) NFPA855 Standard for the Installation of Stationary Energy Storage Systems as well as NFPA68 and NFPA69, standards on explosion protection by deflagration venting and explosion prevention by other means respectively.

Kubik also wrote that “all the largest integrators/suppliers” in the market today complete large-scale fire testing (LSFT), burning complete BESS units. While standards do not currently require this, the forthcoming 2026 edition of NFPA855 is expected to include LSFT.

ESRG’s Nick Warner told Energy-Storage.news that California was among the first jurisdictions to implement the International Fire Code 2018, back in 2020. While it came a little too late for MOSS300, it means that most of the 13GWh+ of large-scale BESS deployed in California as of September 2024 are in line with the code.  

Is this the fourth fire at Moss Landing Energy Storage Facility?

Some reports have claimed that last week’s events marked the fourth fire at the project, but this is not strictly true.

While it is the fourth thermal incident at the Moss Landing complex, the first three were characterised as overheating incidents which did not ultimately result in fires.

It is also important to note that Moss Landing actually hosts two large-scale battery storage projects: Vistra’s 3GWh Moss Landing Energy Storage Facility, and the 182.5MW/730MWh Elkhorn Battery project, which is directly owned by utility PG&E.

Elkhorn Battery—which uses Tesla’s Megapack BESS technology—was brought online in April 2022.

September 2021: A few weeks after Phase 2 of Moss Landing Energy Storage Facility went online, Phase 1 experienced a battery module overheating incident which caused Vistra Energy to take it offline.

Subsequent investigation found that faulty or damaged battery modules were not the cause of that incident, which caused “limited battery damage” to about 7% of MOSS300’s batteries, Vistra said.

Instead, smoke coming from a ventilation unit in the building triggered sprinkler systems which put water onto modules, causing them to short-circuit. The spraying of water onto modules was attributed to faulty couplings in hoses.

February 2022: A similar incident involving faulty sprinkler systems occurred in the 100MW/400MWh Phase 2 of Moss Landing Energy Storage Facility, causing Vistra to take the entire BESS project offline and halt market operation.

In this instance, damage appears to have been even more limited than the first. However, once the early detection system kicked in, local fire crews were called out to the scene which was in line with protocols and what Vistra described as an abundance of caution.

The project owner said it carried out remedial work following both incidents. By June 2022, both systems were fully back online.

September 2022: This time, it was PG&E’s Elkhorn Battery that experienced a thermal incident. This one did result in a fire, although it was contained to one single Megapack BESS unit.

Shelter-in-place orders were issued to local residents while the fire that began at 2am local time 20 September 2022 was declared fully under control by 6.50pm with shelter instructions and road closures lifted.

Moving forward: Future for legacy systems

So, while some media reports can be thought to have understandably misinterpreted or perhaps even sensationalised previous incidents, the timeline of events does speak to the importance of the industry and authorities quickly getting ahead of fire safety issues.

In many ways, this is already happening, with the above-mentioned progress in codes and standards as well as industry best practice.

ESRG’s Nick Warner said the media also has a responsibility to accurately report on these subjects: for instance, he noted that when the Gateway fire occurred, some outlets mentioned a fire raging for two weeks, when in fact the whole incident was over within five days.

Ironically, the previous thermal incidents at the two Moss Landing projects made Chief Mendoza of North County Fire Department as well as California’s main fire agency CalFire, “probably the most experienced fire department in the world in dealing with large-scale energy storage fires.”

Today’s battery storage systems are already far more advanced in their safety provisions than projects built just a few years ago, but Warner said that this doesn’t mean older systems can’t be safe too.

“ESRG has long been of the opinion that even the legacy systems can achieve what we call an acceptable level of safety, and that doesn’t mean that a system without deflagration protection or any kind of fire management is going to be safe when it fails, but we know enough about what the risks are when these systems fail, that the fire department, through training and proper response planning, can manage this in a way that they stay safe, that they can protect other property and other equipment on the site, and certainly they can protect the environment [and] the community,” Warner said.

This article has been amended to reflect that the fire incident at the Gateway BESS project lasted around four to five days and not two days as originally stated.