Duke Energy has activated a 50-megawatt battery energy storage system (BESS) at its former Allen coal plant on Lake Wylie, which serves customers in both North Carolina and South Carolina. The project cost about $100 million and was completed under budget and ahead of schedule. Final testing is taking place this month. Duke Energy also announced plans to build an even larger 167-MW battery system at the same site, with construction expected to start in May.
Both battery systems use lithium-ion technology and qualify for federal investment tax credits that will offset 40% of their costs for customers. This includes an additional 10% credit for investing in a community where the coal plant was retired in December 2024.
“We’re building new resources to keep the Carolinas’ economy thriving, while reinvesting in a former coal plant community that helped power this region for decades,” said Kendal Bowman, Duke Energy’s North Carolina president. “Repurposing existing energy infrastructure and taking advantage of federal funding significantly offset costs for our customers while continuing to support rapid growth across the region.”
The utility-scale batteries are designed to provide energy during periods when solar generation is not available, such as early winter mornings, and can store excess energy produced during low-demand periods for later use during peak times. Some of this stored power comes from nearby facilities like the Catawba Nuclear Station.
Duke Energy’s 2025 Carolinas Resource Plan, currently being reviewed by state regulators, proposes adding 6,550 MW of battery storage by 2035 throughout North Carolina and South Carolina. According to company estimates, this amount of storage could supply more than five million homes during times of peak demand.
The company’s long-term strategy aims to maintain a mix of solar, storage, nuclear, and natural gas generation as customer electricity needs are projected to grow eightfold over the next 15 years compared to the previous period.
Duke Energy also intends to install battery storage at other retired coal plant sites along the Catawba River in Gaston County. Construction on a 115-MW BESS at Riverbend is scheduled for late 2026 with operations starting in late 2027.
“We are proud of how this site and its people continue to support our customers,” said Bryan Walsh, Duke Energy’s vice president of Regulated Renewables and Lake Services. “Multiple former Allen plant employees now work on our Regulated Renewables team, which maintains and operates the new batteries at Allen and elsewhere in the Carolinas. Duke Energy’s test site for new battery technologies, its Emerging Technology and Innovation Center, is also in Mount Holly.”
As part of an ongoing rate review before the North Carolina Utilities Commission, Duke Energy has proposed a third BESS at Allen with an expected operational date by late 2028. The company is also considering building a regional facility dedicated to operations, training, and warehousing related to batteries and renewables that could employ between 20-50 people; these plans require regulatory approval.
Duke Energy Carolinas owns about 20,800 megawatts of capacity serving nearly three million customers across North Carolina and South Carolina within a service area covering approximately 24,000 square miles.
Parent company Duke Energy serves more than eight million electric customers across several states including Florida, Indiana, Ohio, Kentucky as well as North Carolina and South Carolina. The company reports owning over 55 gigawatts of capacity nationwide.
