Critics challenge Duke Energy claims that coal ash risk is low

Duke Energy defended itself from critics who say the company’s assertions that massive coal ash deposits pose no threat to neighbors is based on science skewed to reach that conclusion.

Environmental advocates who hired their own groundwater experts charge that Duke cherry-picked data, made unsupported assumptions and purposely left gaps in the thousands of pages it submitted to North Carolina regulators.

The Department of Environmental Quality has until May 18 to judge the risks posed by ash at 10 North Carolina power plants.

DEQ proposed risk classifications on Dec. 31. A public comment period closed earlier this month with filings by Duke, which says its ash is of low risk, and advocates who argue the opposite.

At stake is how and when Duke’s 32 ash ponds across North Carolina will be closed, as a 2014 state law requires.

“Duke is deliberately playing a game of chicken with DEQ,” said D.J. Gerken, an attorney with the Southern Environmental Law Center. “It failed to produce data DEQ said it needed and is now betting that DEQ will back down and give them a low-risk ranking anyway.”

While the cleanup of coal ash ponds remains a major point of contention in North Carolina, Duke has mollified some of its critics in South Carolina by agreeing to dig up and remove coal ash from waste basins at power plants in Anderson and Darlington counties. Both sites have groundwater contamination, but the thinking is that by removing the ash completely from the old waste ponds, seepage into the ground will stop and pollution levels eventually will drop.

In North Carolina, company officials said Duke stands by its “rigorous study and analysis,” which was done by consultants and reviewed by an advisory board the company created and an electric industry research group.

“Reports questioning industry experts’ science are funded by special interest groups that wish to advance total excavation” of ash, Duke said in a statement. “These groups use the same playbook in many communities and replicate the same legal and scientific challenges all over the Southeast.”

The public comment period, which included hearings near Duke’s plants and filings with the state, are intended to help DEQ make risk classifications for ash at each power plant. The classifications will determine how and when the ponds will be closed between 2019 and 2029.

State law already requires Duke to excavate ash at four of its 14 coal-fired plants, and the company has agreed to dig it up at three more. DEQ proposed in December that risks at four plants be rated intermediate, two low and four of low-to-intermediate.

Duke and its advisory board want the state to rank the remaining seven plants as low risk, the cheapest option. Ponds that hold the ash would be drained and capped to keep out water, but the ash could stay in place and contaminants degrade over time.

Duke estimates it would take at least 18 years, and nearly 1 million truck trips, to haul away the 18 million tons of ash at just one of its power plants, Allen in Gaston County. Excavation, it says, would offer little environmental benefit.

The law center says all seven plants should be rated high risk.

Its experts say excavation would more quickly stop the dispersal of ash elements and recovery of groundwater, which could take hundreds of years. Merely capping the ponds at Allen, one scientist said, would leave up to half the ash still sitting in groundwater and releasing contaminants.

Although Duke and other utilities in South Carolina have plans to remove remove ash from all of their Palmetto State waste ponds, the Savannah River Site near Aiken is leaving some ash in old waste disposal areas and capping it over. Federal officials say that should protect groundwater.

What the data shows

The Allen power plant sits on a peninsula of North Carolina’s Lake Wylie. State health officials advised more than 100 households near the plant not to drink their well water last year before rescinding the advisories in March.

To envision the movement of groundwater under the plant, Duke used computerized simulations called models.

The models and readings from test wells, Duke says, show groundwater contaminated by ash is confined within the power plant’s boundaries and flows east toward the lake. Wells untainted by ash also showed potentially unsafe contamination, Duke says, suggesting it occurs naturally or from other sources in the area.

But two groundwater experts hired by the Southern Environmental Law Center say Duke’s evidence shows no such thing.

The two sides disagree on many aspects of those studies, including these:

▪ The models, the law center argues, assumed without proof that the topography west, north and south of Allen – called “no-flow boundaries” – would prevent contaminated groundwater from flowing in those directions. That meant it could flow mainly east, toward Lake Wylie, and away from the hundreds of homes west of the plant.

The advocacy group insightus, which uses data science to probe social issues, came up with a similar conclusion.

The data Duke used “could have been predicted to flow away from neighborhoods. They simply didn’t analyze the other ones in the other direction,” said president Bill Busa. “When you have 45 data points and you only utilize nine of them, that’s the definition of cherry-picking.”

UNC Charlotte engineering professor John Daniels, who leads Duke’s ash advisory board, said the no-flow boundaries are consistent with test well data and government reports on groundwater in the Piedmont.

“This is a completely reasonable and rational approach,” Daniels said. “The models are not a contrived expression. They’re based on data and on what the science says.”

Daniels said more modeling, including the boundaries, will be needed as Duke moves toward closing its ash ponds. But he said he’s seen no evidence that the company’s ash is affecting neighbors.

Duke points to the absence of boron, which typically appears on the leading edge of ash contamination, as evidence that private wells aren’t being affected by Allen.

▪ Insightus and the law center’s experts both questioned the location of test wells, far from Allen’s ash ponds, that were drilled to show the natural condition of groundwater. Some of those wells may actually be in the path of ash contaminants, they say, skewing results.

Daniels said that is not true.

▪ The critics say Duke’s studies also ignored most of the more than 200 private and public wells west of the power plant whose pumping could draw contaminated groundwater from Allen.

The industry-supported Electric Power Research Institute noted that omission in its otherwise favorable review of Duke’s models. The cumulative impact of the private wells “may or may not result” in contaminants from Allen being pulled off-site toward neighbors, EPRI wrote, recommending further study.

Daniels said no data shows local wells’ pumping reversing the flow of contaminants toward Lake Wylie, but that more studies are underway.

What’s next: DEQ’s decisions

DEQ, meanwhile, said it’s still waiting for data from Duke. Key questions remain about the vertical and horizontal extent of contamination at the power plants and comparison wells drilled to assess groundwater unaffected by ash.

“We don’t feel right now that the data is complete for any of the power plants,” assistant secretary Tom Reeder said. “Our experts are concerned with whether background monitoring wells are really background and some conditions constrained the possible outcomes in terms of (groundwater) flow.”

The Southern Environmental Law Center accused the department of favoring Duke, letting lack of data justify lower risk ratings and “ignore science in service of a predetermined political end.”

DEQ temporarily labeled four power plants, including Allen, as low to intermediate risk in January because it had incomplete data from Duke.

If that data isn’t in hand by the May 18 decision date, Reeder said, “we are going to err on the side of protecting public health and the environment, and we’re going to rely on science to get us there.”

An oversight board, the Coal Ash Management Commission, was disbanded in March after the state Supreme Court ruled legislative appointments were unconstitutional. That means the department’s decisions become final 60 days later after May 18.

Lawsuits are expected to follow.

The State’s Sammy Fretwell contributed.

This story was originally published April 27, 2016 at 11:50 AM with the headline "Critics challenge Duke Energy claims that coal ash risk is low."