An idea of just how big North Carolina’s coal-ash problem is can be found north of the Triangle on the Virginia border in Person County.
There, one small step toward cleaning up accumulated decades of residue from coal-fired power plant combustion is about to begin at the Mayo Steam Electric Plant near Roxboro.
Environmentalists say the new landfill there is proof that coal ash can be contained more safely than in Duke Energy’s leaking basins, where it threatens to pollute waterways, as shown by the February spill of 39,000 tons of coal ash and millions of gallons of wastewater into the Dan River from the plant in Eden.
“This landfill shows that Duke can store coal ash in this way, and this approach can be taken for other sites in North Carolina,” said Frank Holleman, a lawyer with the Southern Environmental Law Center.
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But there is no single landfill that is both lined and big enough to handle the 100 million tons of ash submerged in 33 water basins at 14 plants around the state. Duke officials say closing all the ponds will take 30 years, a timeline the state Senate disputes, suggesting 15 years is possible.
Last month, Duke finished construction of the Person County landfill, outfitted with the latest leak-prevention technology. The state Department of Environment and Natural Resources this month issued an operating permit for the landfill. It will soon start accepting the company’s dry coal ash and eventually be covered with a synthetic liner.
But the potential success at the Mayo landfill also illustrates just how big the problem is. It took Duke Energy the better part of a decade to get to this point – the permitting process alone took nearly five years. And it has cost the company about $30 million.
Duplicating the Mayo landfill across the state isn’t possible, Duke says, because each site is different.
While the new landfill will accommodate the Mayo plant’s coal ash, which amounted to nearly 160,000 tons last year, the first phase of the project has a limit of about 400,000 tons. It will be able to accept ash from other Duke plants, but nowhere near the amount sitting in ponds now.
In other words, it’s just a beginning.
“This is a microcosm of how complex ash management is,” Duke Energy spokeswoman Erin Culbert said.
Latest technology at work
Starting at 31 acres and eventually expanding to more than 100 acres, the new landfill will be more than just a big hole with a giant tarp.
It has a double polyethylene liner, which is unusual but not unprecedented in landfill designs, regulators say. A leak-detection system will monitor it to make sure too much water doesn’t accumulate between the liners.
Groundwater monitoring wells will be sampled and the results reported to the state at least twice a year. A leachate collection system is meant to prevent precipitation and moisture in the ash from reaching the bottom liners or groundwater.
The company has owned the property since the 1970s, and the coal-fired plant has been operating there since 1983. It was supposed to have two giant ponds, but the second one was never built. The landfill has been constructed on the second parcel.
Nearly one-quarter of the ash produced at the Mayo plant in 2013 was sold to be mixed into material to make roads, bridges and buildings. The company sold about 485,000 tons of ash last year in North Carolina.
The utility has been transporting the Mayo ash by truck to the Roxboro plant 12 miles away since 2009. Reducing the opportunities for pollution during transportation is another advantage of the new site, regulators say.
No one-size-fits-all solution
“I expect we’ll see more of these types of designs in the future,” said Michael Scott, a deputy director at DENR. “Does every landfill have to be built this same way? The rules don’t require it. We believe this is a good design. That’s not to say it’s the only design.”
Every site is different, Scott said, and long-term storage will have to be dictated by the geology at each. That’s the position DENR has staked out in the larger coal ash dispute: that, as much as environmentalists say otherwise, there is no one-size-fits-all solution to make coal ash storage safe. Each site needs its own closure and cleanup plan, the agency contends.
Duke Energy has other double-lined landfills in the state, but they don’t have separate groundwater monitoring devices like the ones at Mayo because they were built at the sites of inactive ash basins, which already had monitoring systems in place. Mayo is the first landfill built on unused land using double liners with leak detection, leachate collection and groundwater monitoring.
So far, only one landfill – at the Belews Creek Steam Station in Stokes County – has been filled and capped.
A decade is an unusually long time for a project like this to get the permits it needs, Scott said. In this case it was because of the size of the project as well as the fact that Person County was also involved in permitting it.
Duke has been converting to handling dry fly ash – a powder-like substance produced in the combustion process – in all of its active units and has stored most of the material in one of seven lined landfills, except for two units at Asheville and one of the Cliffside plants in Cleveland County. It plans to convert those plants or close them down in the near future.
Many of Duke’s active coal units still send bottom ash – a coarse, granular material – to ponds, so these units will have to be converted to dry bottom ash systems before ash ponds can be “de-watered” and closed. De-watering is a process by which ponds are slowly drained, filtered and monitored by state regulators before being released into nearby rivers. Only the Mayo and one of the Cliffside units currently handle fly and bottom ash.
Some environmental groups say de-watering is fraught with the potential to pollute waterways. But Duke says that has to happen before it can stop using the ponds.
Environmentalists want more
Simply capping the basins and leaving the coal ash where it is, as is under consideration, doesn’t stop potentially harmful elements from seeping into the groundwater and possibly into nearby rivers and lakes.
The closest such plant to the Triangle is the closed Cape Fear plant in Chatham County, which the state cited earlier this year for illegally pumping 61 million gallons of wastewater from a pair of ash ponds into a tributary of the Cape Fear River. A pond dam at the plant cracked recently. Groundwater testing has shown elevated amounts of boron, iron, manganese, selenium and sulfates.
The Southern Environmental Law Center, which has been embroiled in litigation with Duke Energy and DENR over coal ash, says what the utility is doing in Person County is what environmentalists have been advocating for all along: storing dry ash in lined landfills away from waterways.
It’s the goal the SELC accomplished in South Carolina, where the utility has been moving its ash from unlined pits to a lined landfill nearby but away from the waterway.
Holleman, one of the organization’s lead litigators in both states, says the Mayo solution illustrates there are often alternatives to trucking coal ash a long way away.
“Duke Energy can clean up its coal-ash storage, protect our communities from catastrophic failure, and stop polluting groundwater, drinking water and rivers,” Holleman said.