The biggest batteries on the planet no longer live in a laboratory or a shipping container. They sprawl across hundreds of acres of desert, wired into the electric grid, and hold enough electricity to keep the lights on for whole communities after the sun goes down. In the California desert, one solar-and-storage complex ranks among the largest energy-storage installations ever built, capable of banking enough power to serve hundreds of thousands of homes for hours at a stretch. Their rise marks a shift in how the grid handles renewable energy, capturing midday solar output and releasing it when demand climbs in the evening.
Inside the Edwards and Sanborn project
The standout example sits in Kern County, California, where the Edwards and Sanborn solar-and-storage project spreads across roughly 4,600 acres, part of it on land leased from Edwards Air Force Base. The complex pairs about 875 megawatts of solar panels with a battery system able to store close to 3.3 gigawatt-hours of electricity, a figure that made it, when fully energized, the largest battery storage system in the world. Building it required roughly 1.9 million solar panels and more than 120,000 individual battery units supplied by several manufacturers. Satellite imagery collected by NASA’s Earth Observatory shows the scale of such desert installations, where rows of panels and battery enclosures stretch to the horizon.
What hundreds of thousands of homes really means
Battery capacity is measured in energy, and the gigawatt-hour is the useful yardstick. One gigawatt-hour is a billion watt-hours, roughly the amount an average home uses over several years, so 3.3 gigawatt-hours represents an enormous reservoir when discharged all at once. Project developers have said the complex can supply electricity to serve on the order of 238,000 homes and displace hundreds of thousands of tons of carbon dioxide each year, according to figures cited in accounts of the project. The important caveat is time. A battery that powers a city for four hours cannot do so indefinitely. Its job is to bridge the gap between when clean power is generated and when it is needed, not to replace a power plant that runs continuously.
Why the record keeps moving
The title of world’s largest battery is a moving target. New projects come online every few months across the United States, China, the Middle East and elsewhere, and the leaderboard reshuffles as each giant is energized. Before the Kern County complex claimed the top spot, the distinction belonged to another California site, the Moss Landing facility, which held around 3,000 megawatt-hours before a fire in one of its buildings in early 2025 damaged part of the installation. That incident underscored both the promise and the growing pains of packing so much stored energy into one place, and it prompted renewed attention to fire safety and spacing in large battery farms. Grid-scale storage overall has expanded rapidly, a trend tracked by the U.S. Department of Energy’s energy storage program, as costs have fallen and utilities have looked for ways to firm up variable renewable power.
The challenges of going ever bigger
Scaling storage to this size brings engineering and safety challenges alongside the benefits. Packing thousands of lithium-ion cells into one location concentrates a great deal of stored energy, and a failure in a single module can, in rare cases, spread heat to its neighbors, a process the industry works hard to prevent through spacing, monitoring and fire-suppression systems. The 2025 fire at the Moss Landing site sharpened scrutiny of those risks and prompted operators and regulators to revisit design standards for the largest installations. Cost is another factor: while battery prices have fallen dramatically over the past decade, building a multi-gigawatt-hour project still requires an enormous upfront investment, and the economics depend on electricity markets that reward shifting power from cheap hours to expensive ones. Land, grid connections and supply chains for cells and raw materials all shape where and how quickly the next record-setter can be built. Even so, the trajectory is clear, with each new project tending to eclipse the last, and analysts expect the title to keep changing hands as utilities and developers race to add storage.
What giant batteries do for the grid
The reason these installations keep getting bigger is straightforward. Solar farms produce their most power in the middle of the day, but electricity demand often peaks in the early evening as people return home, run appliances and switch on lights and air conditioning. Without storage, surplus midday solar can go to waste, and grid operators must lean on fossil-fueled plants to cover the evening ramp. A large battery charges when power is abundant and cheap, then discharges during those peak hours, smoothing the mismatch and reducing the need to fire up backup generators. Batteries also respond almost instantly, which helps stabilize the grid when supply and demand fall briefly out of balance. As more wind and solar come online, energy storage has moved from a niche add-on to a central piece of grid planning, and the record-setting projects in the desert offer a preview of a system built increasingly around capturing power now to use later.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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