US: According to Charlotte Business Journal, Duke Energy has proposed excavating 12 more of its 36 coal ash ponds in North and South Carolina and burying the waste in a fully-lined landfills or structural fill projects.

To date, Duke has proposed closure plans for 24 of the 36 ash ponds. In every case, it has proposed excavation and reburial. However, Garry Miller, head of closure engineering for Duke, said that might not be the case for the remaining 12 ponds. He said that the engineering work that remains to be done at those plants could yet show that a 'cap in place' process, which critics have said would be insufficient to protect against further contamination of groundwater, can effectively close them.

Miller said that none of the waste ash from Duke's 36 ash ponds would undergo beneficial reuse, the process of using the ash for commercial products such as a replacement for Portland cement in concrete and gypsum board. However, he added that Duke does send a portion of the dry ash it is currently producing at its largest plants for reuse. However, the time constraints imposed by North Carolina's Coal Ash Management Act of 2014 make it impossible for the existing ash ponds. "As we close these basins, the quantity in them is such that the market cannot handle it in a timely manner," said Miller.

Duke's current cost estimate for closing the ponds is US$3.4bn, although this is subject to revision.