Battery storage capacity in the United States has surged from almost nothing in 2010 to 20.7 gigawatts in July 2024, equivalent to the output of about 20 nuclear reactors.
The rapid growth in storage saw five gigawatts added in the first half of 2024 alone, reports the U.S. Energy Information Administration (EIA).
The EIA predicts this capacity could double again to 40 gigawatts by 2025 with planned expansions, writes The Guardian.
This scale of deployment places battery storage in the key role of maintaining electricity supply as intermittent renewables like wind and solar are added to the grid, the EIA says. They also balance supply and demand, “moving electricity from periods of low prices to periods of high prices,” storing energy to be used when needed, rather than curtailed when supply outstrips demand.
“It’s still technology that we are getting used to working with because the system wasn’t designed for it, but from a reliability perspective it presents a golden opportunity,” said John Moura, director of reliability assessment and performance analysis at the North American Electric Reliability Corporation.
“This changes the whole paradigm of producing electricity, delivering it, and consuming it,” Moura added. “Storage gives us a bit of a time machine to deliver it when we need it.”
Battery storage systems are secondary sources of power because they do not generate electricity themselves. Instead, battery storage operators purchase electricity during periods of high supply—say, in the middle of a sunny day—and release it back to the grid when supply can’t meet demand, like in the evening when the sun goes down but people still need cooling, appliances, or connectivity.
Moura says batteries help grid operators manage what Germans call “Dunkelflaute”—or a “dark lull” when the wind isn’t blowing and the sun isn’t shining. That’s when energy storage steps up, making it a key resource for countries looking to decarbonize their energy systems with renewables.
Buying electricity when it is cheap and selling it later for a higher price can also be a good opportunity to generate revenue. But when batteries are operated only to maximize profits, they may actually increase overall emissions. That’s what happens if the stored electricity is sourced from fossil fuels.
And battery storage still has its limits. Grids will need other investments—like for upgrading power lines—to deploy enough renewables to fully decarbonize power generation.
“There are a lot of changes happening, but monstrous action is still needed if we are going to make this energy transition,” Moura said.
