Giant Battery Powers 50,000 Homes at Former Coal Plant Site

A giant battery is now humming with life where coal once burned in Gaston County, North Carolina, and it's helping solve one of clean energy's biggest challenges.

Duke Energy brought a 50-megawatt battery online this week at the former Allen coal plant site, which shut down in 2024 after decades of operation. The 54-unit system can store 200 megawatt-hours of energy, enough to power every home in nearby Belmont for over a day.

The battery tackles a problem that's stumped energy planners for years: what happens when the sun sets and solar panels go dark, or when wind stops blowing? This storage system captures excess energy during the day when solar farms are producing more than people need, then releases it during peak evening hours when families come home and crank up their thermostats.

"When you're bundled up, get up in the morning, getting dressed, everyone's thermostats come on," Duke Energy spokesperson Bill Norton explained. "That's really when battery systems come to life."

The timing couldn't be better for North Carolina's energy grid. The state is actively decarbonizing its power supply, and batteries serve as a bridge between renewable generation and constant electricity demand. The battery can charge up during sunny midday hours with cheap solar power, then discharge when energy costs more and demand peaks.

The project finished ahead of schedule and under budget, partly thanks to federal tax credits that made the $100 million investment more affordable. Those same credits are helping Duke plan an even bigger battery at the site: a 167-megawatt system that would be the utility's largest to date.

The Ripple Effect

This single battery is just the beginning of a much larger transformation. Duke Energy plans to bring 6,550 megawatts of battery storage online across the Carolinas by 2035, enough to make renewable energy reliable around the clock.

The former coal plant site still has extensive transmission infrastructure in place, which means Duke can add hundreds more megawatts of storage without building new power lines. Construction on the next battery starts in May 2027, and Norton says the company is already eyeing additional projects for the location.

Duke currently operates 253 megawatts of energy storage across nine sites in the Carolinas. Each new battery makes it easier to retire fossil fuel plants while keeping electricity flowing reliably to homes and businesses.

By storing energy when it's plentiful and releasing it when it's needed most, these batteries help reduce the amount of new power generation Duke needs to build. That means lower costs for ratepayers and fewer emissions warming the planet.

Where coal smokestacks once stood, clean energy storage is now lighting the path forward.