TERRE HAUTE —
Duke Energy’s Wabash River Generating Station is similar in design and construction to a retired power plant in North Carolina where 50,000 to 82,000 tons of coal ash spilled Sunday into the Dan River.
Duke Energy said that up to 27 million gallons of water, containing the coal ash, was released from an ash storage pond into the Dan River at the utility’s retired power plant in Eden, N.C.
Coal ash is the material left after coal is burned. Coal ash contains metals such as mercury, lead, arsenic and other heavy metals, which can be toxic in high concentrations.
Duke said a 48-inch stormwater pipe broke beneath an unlined, 27-acre ash pond, sending water and ash into the pipe and into the river. That power plant was retired in 2012.
Now Duke Energy is taking steps to ensure a similar situation doesn’t happen at the Wabash River Generating Station. The site, about 2 miles north of Terre Haute, contains a metal pipe that allows storm water to move from the west side of a coal ash storage area to the lower east side and drain into the Wabash River, said Angeline Protogere, Duke Energy spokeswoman.
The stormwater pipe goes under one part of the coal-fired electrical power plant’s ash storage area that is dry and currently has weeds growing on top of it.
The pipe was last examined by an independent inspector in 2010 and was determined to be sound at that time, Protogere said.
“We take what happened in North Carolina very seriously,” Protogere said, “and so, out of an abundance of caution, we are planning another inspection at Wabash River Station.” Duke Energy conducts monthly, quarterly and annual inspections of the ash storage area and has an independent firm complete inspections every two to five years, Protogere said.
Because the Wabash Station will be retired, Duke Energy plans to decommission the ash ponds/storage areas.
“Several top national engineering firms with experience in ash pond closure work will be bidding on the work this month.” Protogere said. “Engineering work will begin in April, and the conceptual design phase will be completed later this year. Final design and permitting will be taking place in 2015. We will be looking at the pipe as part of that process and how best to decommission the ash basins,” Protogere said, adding that work was previously planned and unrelated to the North Carolina incident.
The design to decommission the ponds will include whether to leave the ash in the ponds or to remove and haul away the ash, Protogere said.
There are four ash ponds/storage areas being used at the Wabash River Station, constructed between 1968 and 2005, ranging in size from 7 acres to 70 acres, Duke Energy reports.
The south pond, which contains water, is lined with two feet of compacted clay and contains a special liner. The pipe does not go under this retention area, Protogere said.
Ash and water move through the manmade pond/storage areas before water is discharged into the Wabash River. The water discharged is regulated by Duke Energy’s National Pollution Discharge Elimination System permit, based on state water quality standards, Protogere said.
The Wabash River Station’s coal-fired units were built in the 1950s and 1960s, capable of producing 668 megawatts. Duke Energy will retire four of the units to comply with a new federal mercury rule. “We are exploring converting another unit to natural gas,” Protogere said.
Wabash Valley Power Association owns Unit 1 at the power station. Unit 1 is powered from synthesis gas from an adjacent coal gasification plant co-owned by WVPA and SG Solutions.
Reporter Howard Greninger can be reached at 812-231-4204 or firstname.lastname@example.org.