Introduction
On Saturday, August 31, 2025, the quiet ranchlands near Parkfield, California, were anything but calm. A fire broke out at the California Flats Solar Project, a facility that powers Apple’s operations and stands as one of the most prominent solar-plus-storage sites in the state.
Two Tesla Megapacks ignited, raising alarm bells across both the local community and the energy industry at large. The good news? The fire was contained. No injuries. No widespread environmental damage. But this was yet another wake-up call.
As Battery Energy Storage Systems (BESS) take on a larger role in our clean energy future, the risks they carry are becoming harder to overlook. That makes it more important than ever to rethink how we approach BESS safety.
Let’s break it all down.
Incident Recap
On Saturday, a fire broke out at the California Flats Solar Project, located southeast of Parkfield in Monterey County. The facility is a significant site in California’s renewable energy infrastructure, combining 130 MW of solar photovoltaic generation with a 240 MWh battery energy storage system composed of 85 Tesla Megapack units. The project was developed on land owned by the Hearst Corporation and supplies clean energy to Apple under a long-term power purchase agreement.
The incident began in the late morning, when two Megapack battery containers ignited. Emergency calls initially misidentified the fire as a vegetation or brush fire. However, upon arriving at the scene, responders from CAL FIRE determined the source was in fact a battery-related fire within the energy storage array. The Monterey County Sheriff’s Office quickly issued an evacuation order for a two-mile radius, affecting five rural residences in the surrounding area.
Tesla’s Field Response Team was dispatched to the site to evaluate the situation. After conducting a safety assessment, they determined that the fire had stabilized and posed no further danger to the public. The evacuation order was lifted later that evening. Fire crews continued to monitor the scene through the night, using a containment approach that allowed the burning battery units to extinguish themselves under controlled conditions. Despite the fire, the situation was managed effectively, and no injuries or off-site damages were reported.
Emergency Response
This wasn’t the first time a BESS fire demanded an all-hands response in California, but the coordination here deserves recognition.
- Initial confusion: First responders were dispatched under the impression it was a grass or brush fire.
- CAL FIRE arrived on site and quickly realized the source: two burning Megapack containers.
- Monterey County Sheriff issued an evacuation order covering a 2-mile radius, affecting about five rural residences.
- Tesla’s Field Response Team was promptly dispatched to assess the damage. By evening, they concluded the fire had stabilized, and the evacuation order was lifted.
- Fire crews monitored the site overnight, allowing the units to burn out under controlled conditions.
This was preparation and protocol. But relying on burnouts as a containment strategy? That’s not sustainable for the future.
Technical Analysis
Let’s dive into the hardware and what we know so far:
- Battery System: Tesla Megapack, containerized grid-scale BESS
- Total Capacity: 240 MWh
- Cooling Method: Liquid-cooling
So, what caused the fire? We don’t know yet. No official cause has been released. But based on previous incidents with Megapacks and similar systems, a few possible culprits come to mind:
- Coolant leak causing a short circuit
- Internal cell defect triggering thermal runaway
- Water intrusion due to sealing or venting errors
The fire was contained to two Megapacks and didn’t spread. That’s the silver lining. But it also underscores how fragile even “safe” systems can be when exposed to mechanical or environmental stress.
Broader BESS Safety Context
Across the globe, several incidents involving Tesla Megapack systems have highlighted the persistent safety challenges in grid-scale lithium-ion storage. Despite advances in design, cooling, and monitoring, fires continue to occur under specific failure modes.
1. PG&E Elkhorn Fire (2022)
Located at Moss Landing and operated by PG&E, this 182.5 MW / 730 MWh Tesla Megapack site experienced a fire in September 2022. Investigators traced the cause to rainwater intrusion through a misinstalled vent, which resulted in internal electrical faults and thermal runaway. One unit was destroyed, and PG&E subsequently retrofitted 88 other Megapacks on-site with corrected venting components.
2. Victorian Big Battery Fire (2021)
In Australia, a Megapack caught fire during testing due to a coolant leak that led to internal shorting and thermal runaway. The fire spread to an adjacent Megapack, resulting in the total loss of two units. Fire crews managed the event over three days, using a strategy of containment rather than suppression.
These incidents highlight the need for stronger safeguards against water intrusion, coolant failures, and thermal runaway. While Tesla has made improvements, the Megapack still depends on conventional lithium-ion architecture, which remains vulnerable under specific failure conditions.
The key takeaway? Even advanced systems carry fire risk. Containment alone isn’t enough. It’s time to rethink system design with redundancy, thermal integrity, and true fire prevention at the core.
Difficulties Extinguishing Lithium-Ion Battery Fires
Here’s the hard truth: fighting a lithium-ion fire is incredibly difficult.
This is because of thermal runaway. Once one cell overheats and fails, it spreads heat to nearby cells. Each one ignites in turn. It’s a chain reaction.
The fire sustains itself, feeding on internal energy and even generating its own oxygen in the process.
So, let’s talk about suppression:
- Water? It’s dangerous. It can trigger violent reactions with lithium compounds.
- Foam? It is often useless. It won’t reach internal cells or slow runaway reactions.
- Letting it burn out? Sadly, it is often the safest option.
That’s exactly what happened at California Flats. The fire crews knew better than to risk escalation. They let it smolder and watched it closely. Smart move, but not a scalable solution.
And while that strategy may prevent injury, it doesn’t eliminate another danger: emissions.
When lithium-ion batteries burn, they release a cocktail of toxic and environmentally damaging compounds:
- Hydrogen fluoride (HF), a highly corrosive gas that can cause respiratory harm
- Carbon monoxide (CO) and carbon dioxide (CO₂), contributing to both acute danger and climate impact
- Particulate matter and organic solvents, harmful to lungs and long-term air quality
Even a small fire like this one, involving just two containers, can release thousands of kilograms of greenhouse gas emissions and toxins. Multiply that by dozens of incidents annually, and it’s clear that these events aren’t just safety failures; they’re environmental setbacks, too.
A Call for Safer Alternatives – EticaAG’s Immersion Cooling BESS
At EticaAG, we believe battery safety starts with design, not damage control. That’s why we developed a fundamentally safer architecture built to prevent fires, not just survive them.
What Makes EticaAG Safer by Design
- Immersion Cooling Technology: Every cell is fully submerged in a nonflammable, nontoxic dielectric fluid that lowers the risk of thermal runaway and eliminates the risk of fire propagation.
- HazGuard Toxic Gas Neutralization: HazGuard detects and neutralizes toxic gases in real time and vents them safely below regulatory thresholds to protect people and air quality during thermal events.
- Active Thermal Control: We use smart liquid circulation to constantly manage and stabilize temperature across the system. This ensures performance without ever compromising safety.
Who benefits from EticaAG’s solution?
- Utilities in fire-prone areas
- Developers looking to future-proof assets
- Communities concerned about safety near grid infrastructure
- Policymakers pushing for smarter clean energy standards
Lithium-ion is here to stay. But we don’t have to accept its risks as they are. With Immersion Cooling and HazGuard technologies, EticaAG is proving there’s a better path forward.
Conclusion
The fire at California Flats could’ve been worse. Thankfully, it wasn’t. But that doesn’t mean we should be comfortable with “just two Megapacks” burning.
BESS is essential. But safety must evolve alongside scale.
The energy industry has an opportunity here. Not just to react, but to lead. To demand better. To adopt safer designs that prevent disaster before it happens.
At EticaAG, we’re not waiting for the next fire to prove our point. We’re building the future of energy storage. One that is powerful, scalable, and truly safe.
