Back
A community north of San Diego has blocked a major grid battery that a developer had hoped to build in a residential area near a major hospital.
Independent power producer AES Corp. withdrew its application to develop the Seguro battery system in Escondido, 30 miles from San Diego. The company had intended to fill a former horse ranch with 320 megawatts of battery containers, which would have been one of the most powerful stand-alone energy storage facilities in the country. The facility would have strengthened the Southern California grid late in the day, when solar generation fades and home consumption surges, pushing the state forward on its quest to produce 100% clean electricity by 2045.
But the development ran into a barrage of local opposition, as residents decried adding large-scale power infrastructure so close to homes and 1,600 feet from Palomar Medical Center Escondido, especially given the multiday, high-octane fires at other large batteries in the state. The outcome was a high-profile win for local battery opponents, and a warning sign to developers in famously pro-battery California.
AES said in a statement that it would prioritize other development efforts, but remained ​“committed to advancing projects that can provide the safe, reliable, and affordable power needed to strengthen the region’s electric grid and generate meaningful economic benefits locally.”
JP Theberge, a board member of the Elfin Forest Harmony Grove Town Council who rallied resistance to the battery, framed his neighbors as a victorious David smiting a corporate Goliath.
“The forces of greed are very powerful in this world. The only way to stop them is to be united and determined and forceful,” he wrote in a post on the Stop Seguro Facebook group. ​“This was a great win and we should all be proud of our efforts.”
AES is, to be sure, a profit-driven company, but the vast majority of U.S. energy infrastructure is built and operated by for-profit entities. What AES hoped to profit from was delivering a large amount of emissions-free grid capacity at a time when California desperately needs more of it — and when the nation as a whole is grasping for more power.
Opponents also called out the risks of large agglomerations of lithium-ion batteries, which have in certain circumstances gone into ​“thermal runaway,” when cells heat up and kick off ferocious blazes that spread to all the batteries within reach.
Escondido has experience with batteries. AES built a large-scale lithium-ion battery in 2017 that utility San Diego Gas & Electric owns and operates on its substation property. One battery container at that site caught fire in 2024 and prompted local evacuation orders that were lifted two days later. Two other California batteries loom even larger in the minds of the Stop Seguro advocates: An Otay Mesa battery, also in San Diego County, caught fire and then smoldered for 17 days in 2024, destroying one section of a larger facility. A Moss Landing project had a string of small fires, followed by catastrophic one in January 2025, which forced the evacuation of the surrounding community.
Crucially, those two fires involved older models of battery cells, and a now-outdated design that packed them into buildings, which was like piling dry timber ahead of lighting a spark. Since then, battery cell technology has improved, and the industry has abandoned storing batteries in large buildings in favor of compartmentalized containers spread across a site. These designs are tested to make sure that a fire in one unit cannot reach surrounding units. Thus, a really bad failure could burn up one container but not produce the kind of dayslong conflagration seen in the highest-profile battery fires.
That’s where separating fact from fearmongering can get tricky. Otay Mesa and Moss Landing were approved by the necessary authorities, and then combusted in catastrophic fashion. Any community would be justified in wanting to prevent something like that from happening. At the same time, the physical causes of those massive blazes simply don’t exist in the battery projects that are getting built today.
Even so, Seguro would have pushed the boundaries in terms of proximity to homes and to the hospital. If one container started smoking, that could be enough to force the hospital’s patients and staff to either evacuate or shelter in place. This fact became pertinent to the case, because AES needed the hospital to sign off on running high-voltage wires through its property, which the hospital board voted down in 2024.
Generally speaking, though, recent battery failures have not put a stop to new battery construction.
Elsewhere in California, developer Arevon broke ground this year on a 250-megawatt battery in Daly City, just south of San Francisco. The battery fires in other parts of the state did not stop the company from securing permits and easements to connect to a nearby substation. That project will inject $73 million dollars into the local tax base, and give San Francisco a major new source of on-demand power to carry it through heat waves and other moments of stress for the grid.
Indeed, batteries continue to set records for participation in California’s energy system. On a given spring day, they show up in force in the evening hours, displacing expensive, more polluting gas plants by shifting the day’s solar production to meet the hours of highest demand. On March 29 at 7 p.m., for instance, batteries delivered a record 44% of total electricity demand, with more than 12 gigawatts injected into the grid.
A clarification was made on April 9, 2026: This story was updated to clarify that the battery AES built at the utility substation has been owned and operated by San Diego Gas & Electric since 2017.
.svg)
