Wednesday morning’s gray, drizzling, 45-degree weather provided a near-perfect backdrop for Duke Energy to show off its $100 million, 50-megawatt, four-hour battery energy storage system at its former Allen coal plant in Belmont, less than 20 miles west of Charlotte.
“Think about cold winter mornings, think about everyone getting up and their heat coming on, the coffee pot coming on, or a bigger picture, school systems powering up for the day,” said Duke Energy spokesman Bill Norton. “You know, they had shut down overnight. So that four-hour window, pre-dawn, when everyone’s getting started, and energy needs are really ramping up, that’s the gap that batteries fill really well.”
Duke has just 250-megawatts of battery energy storage system (BESS) now, but has plans for 6.5 gigawatts — a 26-fold increase — by 2035, pending regulatory approval. That’s enough storage to power more than 5 million homes during peak energy use. The 50-megawatt site, which came online in November, can power about 35,000 homes.
Gaston County alone could see about $1 billion of investment in battery energy storage and other grid upgrades by 2028, said Norton.
Duke plans a second, 167-megawatt BESS less than a mile away, closer to the former Allen coal plant turbine building, now being demolished. Construction on that BESS should start in May and come online in the third quarter of 2027, Norton said. A third battery storage system at the former Allen site could come online in 2028. Duke also has its Riverbend site just north in Mount Holly, where it has plans for a 115-megawatt, four-hour BESS that could come online in late 2027. Duke’s Riverbend station operated from 1929 to 2013.
Both the 50MW and 167MW four-hour lithium-ion battery systems qualify for 40% federal investment tax credits, savings Norton says will be passed on to customers. That 40% figure includes an extra 10% for reinvesting into an energy community, according to Duke.
Batteries are a big part of Duke’s plans to meet increasing energy demand, Norton says. Where a coal plant, like the former Allen station, could ramp up or back down depending on usage, the Catawba Nuclear Station 10 miles south of Belmont in the Lake Wylie area of South Carolina, operates continuously. Power from it can be stored at the Belmont site.
“Nuclear stays on around the clock. So, generally speaking, energy needs are lower in the middle of the night. There are still manufacturing plants going in the middle of the night, hospitals needing power in the middle of the night, but energy demand is low,” Norton said. “So, that is a perfect time for recharging battery storage. It’s called load shifting.”
Duke retired the Allen coal plant in December 2024, after it had generated electricity for the Carolinas for 67 years. Much of the 943-acre site along the Catawba River is being used as a coal ash basin, but a BESS takes much less space. The 167-megawatt BESS will be located on about 10 acres of land.
Putting a utility-scale battery system onsite makes financial sense because of the infrastructure in place.
“The vast majority of poles and wires over your shoulders have been here for decades, powering North Carolina and South Carolina customers,” says Norton, “and it continues to do so today, thanks to the batteries that live on in place of the former Allen coal plant.”
EDITING NOTE: Gaston County could see $1 billion of investment by 2028 in battery energy storage and other grid upgrades, according to Duke Energy. This corrects an earlier version of the story. (Kevin Ellis)