Duke Energy Corp. is pushing back on a report that shows widespread groundwater pollution at the nation's coal ash storage facilities.
The report, based on public filings compiled by the Environmental Integrity Project and Earthjustice, documented groundwater pollution at 91% of coal-fired power plants using data made available under a 2015 U.S. Environmental Protection Agency rule. And a majority of the 265 coal plants that have released data to the public pursuant to that mandate report unsafe levels of at least four toxic constituents of coal ash, including arsenic and lithium, the March 4 report found.
The report also listed the 10 coal plants with the worst levels of contamination, ranking Duke Energy Carolinas LLC's G.G. Allen coal-fired power plant site as the second-most polluted in the nation. Initial groundwater testing at that facility required by the CCR rule revealed concentrations of cobalt, which can cause neurological damage, at more than 500 times levels considered safe by the EPA for drinking water, the report noted.
The CCR rule requires coal ash storage sites to initiate closure by October 2020 if they violate a range of safety requirements, including groundwater exceedances. Closure can be performed by fully excavating all of the ash or capping it in place.
The March 4 report faulted the Duke Energy subsidiary for planning to leave 13 million cubic yards of ash in place at the Allen site, arguing that the utility "cannot restore local groundwater and surface water quality unless it excavates the ash and moves it to lined, dry storage."
But Duke Energy called the report "misleading" in a March 8 statement, saying that assertion "is not true and not supported by the science."
"Our basin closure plans are followed by a corrective action plan to address groundwater impacts," the utility said, noting that the CCR rule acknowledges that "capping, followed by corrective action plans, can safely address these impacts." Under the rule, ash basins can be closed in place if they meet certain safety requirements.
Duke Energy also noted that the highest cobalt exceedances were detected at two monitoring wells that are "deep within the interior" of the Allen site and are "flowing away from plant neighbors." Separate testing conducted by state regulators did not detect elevated levels of cobalt in neighbors' wells near the Allen plant, and recent surface water sampling along nearby Lake Wylie "shows no ash basin impacts to surface water," the utility said.
Abel Russ, a senior attorney with the Environmental Integrity Project and co-author of the nationwide report, asserted that the site's coal ash will continue to pollute the underlying groundwater if it is not fully excavated. "If you leave coal ash sitting in groundwater, it will continue to leach toxic pollutants," he said in a March 12 interview. "That's just a fact."
Duke Energy in December 2018 reported that it is "well down the path to safely closing all ash basins." The company plans to close 56 coal ash basins at 21 power plants to comply with state and federal environmental regulations.