As with any development proposal, community opposition is complex and localized. Although easier to hide than wind turbines or solar panels, battery installations can spoil the view and construction work can create noise or dust. But concerns about security have become a powerful driver of the opposition’s efforts. Developers may point to data indicating that grid battery fires are rare, but neighbors will focus on the unknowns. How rare is this? “If there have been fires and explosions, people will connect them to proposed infrastructure in their community,” says Sanya Carley, co-director of the Kleinman Center for Energy Policy at the University of Pennsylvania, who has studied opposition to clean energy projects.
Most headlines about deadly battery fires refer to e-scooter or e-bike batteries, which can be made dangerous by poor-quality components or improper storage. Larger grid batteries perform better. They are generally known to local authorities and composed of parts from reliable sources. An analysis by the California Public Utilities Commission estimates that 2 percent of the grid’s storage facilities will experience “major security-related” incidents, with the risk greatest during the first two years of operation. Most other incidents are dealt with quickly.
But grid batteries carry their own risks, which some experts say should be better explained to potential neighbors. Guillermo Rein, professor of fire science at Imperial College London, says the industry has done an excellent job of making fires rare despite the inherent volatility of lithium-ion technology. But safety measures continue to evolve, he adds, and there are significant gaps in our understanding of how to prevent and mitigate the impact of the most catastrophic fires. “We are catching up,” he said. “The risk is unknown and it must be measured.”
Sparks, arcs and Flames are a risk in any electrical system. When they occur in or around a battery, the consequences can be disastrous. When flames heat a battery cell, one of the repeating components of a larger battery, beyond a certain temperature, a chemical reaction begins that produces more heat, triggering the same process in neighboring cells. Thermal runaway can occur in just milliseconds, before smoke or heat can be detected by an alarm system. The fire spreads first to a group of surrounding cells sharing electronic components, called a module, and then to others, until an entire rack of batteries is on fire.
The first level of fire safety is to prevent that initial spark from occurring. Most fire testing involves detecting defects in individual battery cells, something the industry, which makes millions of these cells each year for all kinds of energy applications, does well, Rein says. But as they are grouped into larger groups for network-wide systems, testing becomes more complex and ignition pathways multiply: coolant leaks, shorting electronics, installation defective. Not all processes are reproducible in the lab, says Rein, author of a 2020 review of battery safety standards, which he describes as “chaotic.”
In the absence of extensive testing of large grid batteries, the “fundamentals” of security design in the grid battery industry are being changed in response to real-world incidents, Rein says. These include a system in Surprise, Arizona, that caught fire in 2019 and then exploded after fire extinguishers mixed with the burning batteries, turning the warehouse they were installed in into a pressure cooker. Nine first responders were injured. Two years later, near Geelong, Australia, a fire broke out during testing at what was then the world’s largest battery facility, a collection of Tesla Megapacks, the manufacturer’s grid-attached storage product of electric vehicles. High winds spread flames from a Megapack to a nearby device, and the fire took four days to extinguish.
In both cases, the industry has learned lessons: Battery containers are increasingly designed to better prevent explosions by venting flammable gases, and made more insulated to prevent flames from spreading from container to container. the other. Controls are more accessible from outside the container. Firefighters are advised to limit the use of extinguishing products, monitor the situation while spraying the surrounding area to contain the fire. Design principles favor fire containment. A single container can catch fire and burn out on its own; the goal is to prevent catastrophic spread and protect first responders.
But strategies for stopping growing fires, including systems to extinguish or contain fires inside containers, vary among manufacturers. “I think there are still a lot of engineering techniques that are considered best practices, but haven’t been completely proven,” says Steve Kerber, executive director of the Fire Safety Research Institute, an affiliate of the Underwriters Institute , or UL, a nonprofit organization that creates the most widely used fire safety standards. Battery systems installed by Vistra Energy at a former natural gas plant in Moss Landing, Calif., were shut down for months after incidents in 2021 and 2022 in which heat suppression systems, intended to curb the thermal runaway, were accidentally triggered, splashing the batteries in water. this caused arcing and short circuits.
