The Dan River coal ash spill has forced some serious discussions about the future of Duke Energy’s North Carolina coal fleet.

Duke Energy President and CEO Lynn Good said in a March 12 letter to Gov. Pat McCrory (R) and Department of Environment and Natural Resources (DENR) Secretary John Skvarla that the company is planning to convert three of its remaining North Carolina coal-fired units—the 556-MW Cliffside 5 and both Asheville units (a combined 376 MW)—to dry fly ash systems or retire the units.

The plan is part of a comprehensive recommendation in response to a Feb. 25 request from Gov. McCrory—a former long-serving Duke Energy employee—for the company to provide plans for coal ash ponds at its facilities. The governor’s letter called for options, priorities, alternatives, preliminary designs, cost estimates, and any other pertinent information concerning Duke Energy’s coal ash plans to be provided by March 15.

Good’s response noted that Duke Energy had accepted responsibility for the Dan River ash discharge and included a description of the actions the company had taken following the event, which was discovered on Feb. 2.

The company’s plan includes both near-term and longer-term actions. Duke Energy is responsible for 21 ponds at seven retired sites, as well as 12 additional ponds at seven active sites. Actions proposed, in addition to the Cliffside 5 and Asheville unit decisions, include:

Permanently closing the Dan River ash ponds and moving ash to a lined structural fill solution or a lined landfill.

Closing the Sutton ash ponds once lined structural fill solutions and other options are evaluated.

Moving ash from the Riverbend site to a lined structural fill solution or a lined landfill.

Moving ash from the Asheville plant to a lined structural fill solution while continuing to search for reuse opportunities for the ash.

Accelerating water removal from ash ponds at all retired coal plants.

Conducting engineering reviews of all the company’s ash basins to confirm structural integrity and evaluating stormwater discharges near the basins.

Duke Energy’s considered retirement of the Cliffside 5 and Asheville coal units is significant because the units have already undergone major upgrades. Selective catalytic reduction systems were installed to reduce nitrous oxide emissions and flue gas desulfurization systems have been installed to reduce sulfur dioxide emissions. The projects were hefty investments expected to help the plants remain in operation well into the future.

Good suggested that close coordination with the DENR and the Environmental Protection Agency (EPA) would be needed. She noted that all decisions would need to align with the EPA’s final coal ash rule—expected to be issued in December—and with the EPA’s steam electric effluent guidelines regulating wastewater streams—expected no earlier than May.

In a statement, DENR Secretary Skvarla made it clear that Good’s response was inadequate. “There are far too many questions left unanswered and Duke Energy should provide the information we originally requested, including the estimated costs of cleanup, plans for the future and a detailed timeline,” he said.

“This department is moving forward immediately with mechanisms to not only derive the necessary information, but to also enforce stringent timelines for fulfillment and completion of Duke Energy’s obligations to protect public health and the environment.”

—Aaron Larson, associate editor (@AaronL_Power, @POWERmagazine)