California's Battery Storage Fire: Precursor Or Outlier ...
A fire broke out at the Moss Landing Power Plant, not too far from San Francisco, on January 16, 2025, prompting the evacuation of approximately 1,500 residents and the temporary closure of Highway 1. No one was harmed in the incident. Given the massive growth in grid storage battery systems, is this something everyone should be worried about, and is it likely to recur? No and no.
Firefighters allowed the blaze to burn out, citing the challenges of extinguishing lithium-ion battery fires. Authorities lifted evacuation orders the following day after air quality tests confirmed safe conditions. The first phase facility has 300 MW of capacity and about 40% of it was destroyed, roughly 120 MW. Phase 2 and 3 added another 450 MW. Given the value that batteries have been providing in flattening the duck curve in the state, this is going to have some grid impacts. However, the state has over 10,000 MW of battery capacity, so missing 1.2% of it isn’t going to be a big deal.
Global Comparison
In the United States California is the storage leader, unsurprisingly, but there’s another 5,500 MW or so scattered around other states. Globally, there are about 400,000 MW of battery capacity on grids, so this represents 0.03% of the world’s current capacity. In other words, this isn’t a significant portion of California’s, the United States or the world’s battery capacity that’s out of service. To put US battery storage systems in context, the roughly 15,500 MW it has deployed is less than a single December auction in China, in which 76 bidders averaged US$66 per kWh for 16,000 MW of requested capacity.
Let’s do some rough statistical comparisons to some recent hydrogen for energy data out of South Korea. Testing on 147 hydrogen buses after one exploded at a refueling station in December found that 11%, one in nine, were leaking. Testing on hydrogen cars in the country found that 1,463 out of 9,482, 15.4%, were leaking. There have been three explosions and fires at the 203 hydrogen refueling stations in the country that I’m aware of, so 1.5% of them, killing two people and hospitalizing nine to date.
Storage Safety Measures
Phase 1 of the facility, commissioned in December 2020, is housed within a repurposed turbine building at the former Moss Landing Power Plant in California. The facility contains 4,500 battery racks arranged in sections, each equipped with dedicated cooling and fire suppression systems. At the time of construction it was one of the biggest battery storage facilities in the world. There were a couple of previous thermal incidents in 2021 and 2022 which were contained and attributed to a faulty sprinkler system.
As one of the earliest storage systems, the facility predates leading practices for battery systems. Authorities having jurisdiction are now mandating Large-Scale Fire Testing (LSFT) to ensure safety and compliance. Traditional evaluations, such as UL 9540A, assess thermal runaway and fire propagation at the cell, module, and system levels.
Modern Advancements
Further, modern grid storage systems tend to be outdoors on concrete pads with containerized and air gapped battery units. Tesla was a western leader in containerized batteries with its Megapack, as Wärtsilä’s Vice President of Energy Storage & Optimization Andy Tang told me a few years ago when we recorded a CleanTech Talk, but it’s now the dominant model by far because they can be built in factories and delivered like any other container. The air gaps means that if thermal runaway happens in one container, it’s much less likely to spread to other containers. The 182.5 MW of Tesla Megapacks at the Moss Landing facility are deployed like that and were unaffected by the fire.
Key Takeaways
EPRI and TWAICE used their global data set of battery incidents, used by the industry for root cause analysis, to assess the change in statistical likelihood of battery energy storage systems over time, making it publicly available in May of 2024. The likelihood of failures has plummeted due to changing chemistries, air gapped open air containerized deployments, and the new standards for battery and thermal management systems to the global industry is using.
Statistically, it’s clear that battery electric cars are vastly less likely to catch fire, although the characteristics of the fires are different. Specialized fire extinguishers designed for lithium-ion batteries, fire blankets to contain and isolate burning EVs, and advanced cooling agents are being deployed to improve firefighting effectiveness. Additionally, fire departments are undergoing specialized training to handle thermal runaway risks and the complexities of extinguishing EV fires, which often require prolonged cooling periods and different tactics compared to conventional vehicle fires.
Comparison with Natural Gas
Similar to the comparison between EVs and internal combustion cars, it’s worth asking what the comparison is between natural gas electrical generation turbines and battery grid storage. Interestingly, there is no global data set on turbine fires and failures, so researchers have to assemble their own. That said, a paper presented at the 6th European Conference on Industrial Engineering and Operations Management in Portugal in July of 2023 on reducing fires at turbine facilities is pertinent. These are just the big ones at these facilities. As there is no statistical data on prevalence of fires at gas turbines, it’s impossible to draw a clear conclusion, but when the entire focus of the site is moving a flammable and explosive gas into the site and burning it, my assumption is that it’s quite probably much more likely from an incident per GW perspective.
As a contrast, there are no recorded fatalities due to fires at operating grid battery storage system facilities that I have been able to find. This makes sense because battery systems are solid state. They are lights out facilities with no staff on site except possible security guards, unlike gas generation facilities.
Once again, battery fires have unique characteristics and there are potential health concerns, hence the precautionary evacuation. Air quality monitoring at Moss Landing has so far detected no significant levels of toxic gases such as hydrogen fluoride or particulate matter.
Meanwhile, when used as directed, combustion of natural gas releases carbon dioxide, a greenhouse gas contributing to climate change, along with nitrogen oxides, which can form smog and acid rain. Incomplete combustion may also produce carbon monoxide and trace amounts of volatile organic compounds. Additionally, methane leaks during production and transport can significantly amplify greenhouse gas emissions.
Nitrogen oxides contribute to respiratory issues such as asthma and bronchitis by forming ground-level ozone and fine particulate matter. Exposure to these pollutants has been linked to cardiovascular diseases and increased hospital admissions, particularly among vulnerable populations. Natural gas plants can emit trace amounts of hazardous air pollutants, including benzene and formaldehyde, which have been associated with long-term health effects.
