Around 3 pm on Thursday, January 16, the world’s third-largest lithium-ion battery energy storage system (BESS), accounting for about 2 percent of California’s energy storage capacity, caught fire and quickly erupted in an inferno that lit up the horizon for miles around. Owned by the Texas-based Vistra Corporation, the 300 MW system experienced system failure in the fourth such incident the complex has experienced since 2021. Officials promptly closed part of Highway 1 for three days and issued an evacuation order for roughly 1,200 nearby residents until the following evening when air quality monitoring showed no threats to human health. Inspections on Sunday morning showed no active flames, and by Wednesday there was only minor smoldering reported.

Emergency responders were able to keep the fire limited to the repurposed turbine hall housing the BESS, which was Phase 1 of four separate battery systems located at the Moss Landing Power Plant complex; the others were unaffected. The primary hazards beyond the actual fire were the particulates and hazardous chemicals released, but through diligent air quality testing it was determined that favorable wind and atmospheric conditions prevented the smoke from reaching ground level — a lucky break for the foggy Central Coast. Some residents reported headaches and respiratory problems, although so far these appear to be minor in severity. Unfortunately, elevated levels of nickel, manganese, and cobalt nanoparticles were detected in the soil of the surrounding area, which includes the nearby Elkhorn Slough and Salinas River; further testing is needed to determine the impact on local wildlife.

This incident naturally raises concerns about the safety of large lithium-ion battery installations, especially in light of the three previous battery fires at the site; concerns that are already being acted upon by local and state officials. The Monterey County Board of Supervisors held a special meeting on Tuesday, January 21, and unanimously approved declaring a state of emergency as well as sending a non-binding request to Vistra and Pacific Gas & Electric to keep the facility offline until the cause of the fire is determined. The County is also forming a special unit to monitor and communicate the fire’s air quality impacts, and is being assisted in investigating and remediating the site by a multitude of state agencies including the EPA, the Energy Commission, the Public Utilities Commission, and the Department of Toxic Substances Control. While the full scope of impacts will only become clear with time, what do we know now that can help us understand what, if anything, this incident says about the risks associated with large-scale BESS?

To take a little step back, all forms of energy storage and generation inherently carry some risk, simply because energy is the capacity to make things happen. And the more energy you have concentrated in one location, the greater the risk. This is true for everything from oil, coal, and uranium to dammed waters, compressed air, flywheels, and, of course, batteries. So the issue is not whether we can make a 100 percent safe battery, but if we can adequately manage the risk to an acceptable level while maximizing the benefits. Was there more that could have been done to make the Moss Landing Phase 1 battery system safer?

In short, yes; there were at least three factors at play that increased the risk of catastrophic failure. First, the battery that burned was the oldest of the four systems installed at the site and utilized a lesser-used, more fire-prone type of chemistry. Second, it was housed indoors in an old building; current industry standards call for large batteries like this to be sited outdoors on physically spaced concrete pads to prevent the fire from spreading. And third, the fire suppression system used has been implicated in starting all three previous fires experienced at this site since 2021, all of which were started by water leaking from pipes onto the battery cells directly or on other electrical equipment in the room (first, second, third).

A modern BESS would not have this combination of risk factors, making the repeated failures of the Moss Landing system a fairly unique case; one that will become even rarer as time goes on. Recent DOE studies show that BESS failure rates have plummeted while deployment has skyrocketed, providing clear evidence that this technology is getting safer and more reliable as the industry develops. And even looking at the severity of the Moss Landing BESS fire, this was one of the largest lithium-ion batteries in the world, located in a sensitive ecological area, suffering a worst case scenario meltdown — yet no one was injured, and there was relatively minor environmental damage and only brief interruptions to daily life for nearby residents.

So while this event should be taken seriously (as state and local officials are), it should not be taken as representative of the industry as a whole. California and the world need forms of energy storage, especially as solar and wind energy continue to grow, and lithium-ion batteries have proven to be safe, reliable, and valuable assets in our journey toward a climate-friendly future.

Interested in the specific regulations that keep modern battery storage systems safe? Check out this new fact sheet from the California Solar + Storage Association for more details.