A two-unit, combined-cycle gas-turbine (CCGT) station built to replace an older coal-fired power plant is now fully operational and delivering electricity for Duke Energy’s customers in North Carolina and South Carolina.
The new Asheville station in Arden, N.C. is deemed to be 75 percent more efficient than the 1960s-era coal-fired plant which was shut down in January. Demolition of the Asheville coal-fired site is underway and expected to be finished by 2023.
“Customers want cleaner, more reliable energy, and we’re committed to delivering on this expectation,” said Kevin Murray, Duke vice president of project management and construction. “By building the new Asheville station, we’re significantly reducing air emissions — including carbon dioxide, sulfur dioxide and nitrogen oxides — and continuing to move toward our companywide goal of cutting carbon dioxide emissions by 50 percent by 2030.”
The Ashville combined cycle station cost about $817 million to build. The first 280-MW unit came online in December 2019, while the second 280-MW power block went into commercial operation in April.
Carbon dioxide emissions at the site have dropped by about 60 percent per MWh in comparison to the now-retired coal plant, according to Duke Energy. Sulfur dioxide is expected to decrease by 99 percent and nitrogen oxides by 40 percent. Mercury has also been eliminated.
Duke has committed $1.4 billion in capital expenditures to provide power with lower emissions in the Asheville region. The utility is spending $175 million on upgrading transmission lines, substations and some undergrounding of distribution lines.
A 17-MW battery storage system will be built at the Asheville site, while Duke also plans to invest in a 10-MW solar plant. The renewables side of the Asheville plan will cost close to $120 million.
Some environmental and advocacy groups opposed Duke’s CCGT station early on, but the project won state and federal approval by 2017.
The Asheville units use combustion turbines and generators with bypass stacks. These allow the combustion turbines to operate when the heat recovery steam generator or steam turbine generator are offline for maintenance work.
The station can also burn diesel if natural gas is unavailable.
(Rod Walton is content director for Power Engineering and POWERGEN International. He can be reached at 918-831-9177 and firstname.lastname@example.org)