Battery Fires Prompt New Push for Safety

A major fire at a battery station at Monterey Bay has raised safety concerns, just as energy storage takes off in California. Power suppliers, regulators, and safety officials are revisiting rules and protocols to ensure battery storage remains a viable path to a cleaner energy system.

The plant, owned by Texas-based Vistra Energy, caught fire in January 2025, burning up tens of thousands of batteries and forcing 1,200 residents to evacuate. While the damage was significant—including toxic chemical deposits in prime farmland and the fragile wetland of Elkhorn Slough—the incident has reinforced the value of updated industry safety standards that most California battery facilities now follow.

Although Ava does not receive power from the Moss Landing station, we are doing our part to ensure that the battery storage facilities in our portfolio meet the most up-to-date fire safety standards so that similar incidents do not occur in the future. We believe that California can continue building a cleaner, more reliable energy grid without sacrificing public safety.

Moss Landing, a small coastal town in Monterey County, has been home to a gas-fired power plant since 1950. For a while, it was the largest power plant in California. In addition to causing decades of air pollution, the plant consumed massive amounts of ocean water. Two older electric generation units drew 890 million gallons of water per day—a staggering 600,000 gallons per minute—to cool the plant, then discharged the heated water back into Monterey Bay, impacting the plentiful local sea life.

Indeed, the plant is adjacent to Elkhorn Slough, the extraordinary coastal estuary teeming with otters, seals, and seabirds. The National Estuarine Research Reserve is managed by the California Department of Fish and Wildlife and offers picnic areas, hiking trails, and other public recreation opportunities.

In response to state mandates to reduce marine wildlife impacts, older parts of the gas plant were shut down and removed in 1995 and 2016, leaving 1,020 megawatts (MW) of capacity. The changes cut the plant’s water use from 600,000 gallons per minute down to 260,000.

To make up for lost capacity, Vistra installed the first batteries in December 2020. The 300 MW of capacity and 1,200 megawatt-hours (MWh) of energy made it the world’s largest battery installation at the time, enough to serve up to 225,000 households during peak hours.

Utility-scale batteries in California charge during daytime hours when solar energy is plentiful, and release their electricity in early mornings and late afternoons, when energy demand is high and solar electricity is declining.

The first phase of installation was made up of more than 4,500 stacked battery racks or cabinets, each containing 22 individual battery modules. They were put inside a building that used to hold a gas turbine, spanning the length of nearly three football fields.

Vistra expanded the plant in two phases, reaching 750 MW / 3,000 MWh in 2023.

The Moss Landing fire affected the batteries installed in the first phase of the plant. It started on January 16, 2025, and burned for five days, followed by smoldering and a brief reignition in mid-February. Battery fires are largely left to burn themselves out, because they cannot be extinguished with water, can reignite themselves, and are hazardous to firefighters. 

This was actually the fourth incident at this location since 2020, though by far the largest. The Vistra facility had two “overheating events” that stopped short of fire, and the neighboring Tesla Elkhorn battery facility had a minor fire in 2022.

While the cause of the fire is still under investigation, Phase 1 of the Vistra facility was built before safety and design standards had been promulgated, and had a number of shortcomings: 

“The Moss landing facility’s combination of non-standard design, less stable battery

chemistry, and emergency response protocols allowed fire to propagate,” Ava CEO Howard Chang said in a report to the Ava Board.

Altogether, California has about 200 utility-scale battery installations, which account for 85% of the 13,400 MW of total battery capacity in the state. The remaining capacity is from about 200,000 smaller battery installations in homes and businesses.

Ava has 19 utility-scale battery projects under contract, with over 1,000 MW of capacity. So far, eight are in operation (448.5 MW) and eleven more are under development (731 MW), including the 125 MW Kola Energy Storage project located in San Joaquin County. Developed by NextEra, the Kola facility was built using the latest fire safety standards and is slated to come online later this Summer.

Over 94% of utility battery storage facilities in California came online after NFPA standards were established. The NFPA standards dictate testing, fire walls, minimum spacing between units, site-specific hazard mitigations, and emergency response planning. Batteries are now deployed in containers with a dedicated HVAC unit, fire suppression system, automatic shutoff controls, and smoke, gas, and fire alarms. Additionally, most batteries today use Lithium Iron Phosphate (LFP) chemistry, which is considered to be more stable than its NMC alternative.

All of Ava’s projects are designed with outdoor stationary containers, and all were constructed after NFPA 855 was released. Our oldest battery project, permitted shortly after NFPA 855’s initial distribution, recently completed an upgrade to improve safety and performance. 

Battery safety is being addressed through a new order from the Public Utilities Commission. In March, the CPUC modified General Order 167, with new measures to implement and enforce maintenance and operation standards for battery systems, including increased oversight over emergency response action plans.

The fire has also spurred several proposals in the California legislature, including SB 283 authored by Senator John Laird, who represents Moss Landing and the surrounding area. The bill would require all new energy storage facilities to comply with the latest fire safety standards (NFPA 855) and be inspected by a local fire department before operation. The Ava Board of Directors voted to take a support if amended position on SB 283 at its May 2025 meeting.

Ava is continuing to evaluate these proposals and work with our developer partners to ensure safety is the highest priority for all current and future battery storage contracts.