(Photo: The Sutton cooling lake breach flows into the Cape Fear River on September 22, 2018. Credit: Duke Energy)Floodwaters from Hurricane Florence breached a dam at Duke Energy’s L.V. Sutton plant near Wilmington, North Carolina late last week. The flooding prompted the utility to shut down its natural gas power units at the site, and raised concerns about a coal ash spill into the nearby Cape Fear River, the Charlotte Business Journal reported.
Duke Energy issued a statement saying that coal combustion byproducts called cenospheres appear to have washed out of an inactive coal-ash basin at the Sutton plant and into the river, Charlotte Business Journal’s John Downey wrote. These lightweight hollow beads of aluminum oxide and silica have a different chemical makeup than fly ash, bottom ash, boiler slag, and similar materials that are subject to regulation, the utility noted.
On Monday, Water quality tests on the river near the plant showed elevated levels of arsenic and heavy metals downstream from the breach of Sutton Lake Dam, Downey reported.
Originally a 575-megawatt plant dating to 1954, Sutton’s coal-fired units were retired in November 2013. Duke Energy says that removal of the coal plant and older combustion turbines was completed in 2017. A 625-megawatt natural gas combined-cycle plant came online at the site in 2013. Two coal ash basins remain, which the utility says were being excavated and closed prior to the storm.
On Friday, the dam surrounding the plant’s 1,100-acre cooling lake breached, causing water to spill out of two points at the southern end. Duke Energy reported that cooling lake water also spilled into the natural gas plant’s footprint.
“There is an adequate energy supply to serve residential customers,” the utility said. The same day, crews were working to restore power to 26,000 customers still experiencing outages following Florence. At its height, more than 1.8 of their customers in the Carolinas lost power.
Coal Ash Controversy
Duke Energy spokeswoman Catherine Butler told Downey that there is no visible coal ash in the lake or the river, but also said that the utility can’t be sure that no ash has escaped from the storage pond into either water body.
“The breach of the dam imperils two unlined coal ash ponds on site, which contain a combined 2.1 million cubic yards of coal ash, according to a report prepared for Duke Energy this year,” Glenn Thrush and Kendra Pierre-Louis reported for the New York Times. “That amount of coal ash would fill a large sports stadium.”
The Department of Environmental Quality warned that Duke Energy could be held accountable for any environmental consequences resulting from the leaks, spills, and overflows, News & Observer’s John Murawski reported.
Coal ash is a byproduct of electricity generation that contains toxic heavy metals. In early 2014, a Duke Energy ash impoundment failed, releasing as much as 39,000 tons of coal ash into the Dan River watershed.
As anticipated cleanup costs soared to over $2.5 billion, the utility’s subsidiary Duke Energy Progress requested a rate hike last year that would have increased rates for industrial and commercial customers by 10% on average. North Carolina regulators denied that initial request. Back and forth over rates and cleanup costs continues.
