Duke Energy sets aside $3.4B for coal ash cleanup

The company recently set aside that amount to meet its "asset retirement obligations," or ARO, according to its third-quarter earnings report. Duke officials said that number is subject to revision.

"This estimate will be refined as ash basin closure plans and related strategies are finalized and approved," the company said in a statement.

The General Assembly passed legislation this summer setting a timetable for Duke to close and then cleanup the 33 ash ponds at 14 operating or shuttered coal-fired power plants statewide. The new law sets up a commission that will determine which ponds will be handled first, depending on the risk they pose in terms of groundwater contamination or a leak into nearby surface waters.

Duke executives told lawmakers that the final tally for cleanup could reach $10 billion if the company is required to dig up the ash from every pond and truck it to a lined landfill. Chief Executive Lynn Good said in March that Duke would try to pass along most of the cleanup cost to customers through higher electric rates.

Separately, North Carolina regulators ordered Duke on Thursday to resubmit proposals for assessing the extent of groundwater contamination at the ash ponds, calling the company's current plans, which were submitted in September, "inadequate."

The state Division of Water Resources has given Duke 30 days to file the amended plans. The company is required to perform the assessments under the new law.

Coal ash contains numerous toxic heavy metals, including lead, arsenic and mercury. State regulators have said all of Duke's unlined waste pits are contaminating groundwater.