Monday Numbers: There’s still 100 million tons of coal ash to be excavated from Duke Energy ponds

Millions of tons of coal ash have been excavated from unlined ponds at Duke Energy power plants, but an enormous amount has yet to be dug up, according to the inventory listed in the NC Department of Environmental Quality’s annual coal ash report to the General Assembly.

As of July 2020, there were more than 100 million tons of coal ash remaining in the unlined ponds at 11 of the utility’s 14 plants in North Carolina.

A combination of state law, a consent order and litigation by the Southern Environmental Law Center resulted in the ponds’ closure.

Because of  location, geology, groundwater flow and the amount of ash that must be excavated, dried and then redeposited, each site poses particular challenges and proposed closure deadlines range from 2028 to 2038. Each onsite landfill must be equipped with dual geosynthetic liners and a leak detector system. The consent order also requires the bottom of the landfill to be at least 5 feet above the water table, as well as groundwater and surface water monitoring and regular inspections of the landfill caps and liners for 30 years.

Excavation is complete at several ponds: Asheville (1); Dan River, in Eden (2); Riverbend, in Mt. Holly (2); Sutton, in Wilmington (2); and Cliffside/Rogers (1).

That material is being recycled or disposed of on-site in lined landfills. Material from ponds at Buck Steam Station in Salisbury, HF Lee Plant in Goldsboro, and Cape Fear in Moncure will be reprocessed and recycled into construction material. Ash from Sutton and Riverbend was sent to the Brickhaven clay mine in Chatham County to be used as “structural fill,” although that activity has stopped. Duke has been transporting ash from Weatherspoon, in Robeson County, to South Carolina, according to DEQ’s annual reports.

100,397,000 — Tons of coal ash remaining in Duke Energy’s unlined ponds

16,836,000 — Tons of coal ash in the Marshall Steam Station pond, the largest amount of all Duke’s facilities

1,445 — Number of people living in the census block of the Marshall Steam Station

12,974,000 — Tons of coal ash in the Roxboro West Ash pond, the second-largest amount of all Duke’s facilities

1,693 — Number of people living in the census block of the Roxboro West Ash pond

31 — Total number of Duke Energy coal ash ponds, active and inactive

8 — Number of ponds that have been excavated, to date

The report also breaks down the amount of ash and number of unlined ponds by NC House and Senate districts. Here are the Top 3 districts in terms of tonnage, plus their representatives:

• Senate District 22 (Mike Woodard) and House District 2 (Larry Yarborough): 26,648,000 tons, all at the Mayo and Roxboro plants
• Senate District 42, (formerly Andy Wells, who resigned in July) and House District 89 (Mitchell Setzer): 16,836,000 tons at the Marshall Steam Station
• Senate District 30, (President Pro Tempore Phil Berger) and House District 91 (Kyle Hall) 11,971,000 tons at Belews Creek. The ponds at the Dan River station have been excavated.

Source: Duke Energy, DEQ Coal Ash Impoundments annual report and coal ash quarterly report, submitted Oct. 1, 2020, to the General Assembly

This article has been corrected to reflect none of the Duke Energy ponds are receiving ash.