Side dump truck receiving coal ash at W.S. Lee Steam Station in Belton, S.C.

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  • Ash now being moved at several coal plants across the Carolinas with more to be added soon.
  • Company uses strict set of guiding principles to inform closure work.
  • Explains multiple ways to safely close basins.

Duke Energy continues to deliver on its commitment to safely close coal ash basins across the Carolinas. We are currently moving ash at several sites into new fully lined storage solutions while we continue to review smart options for the remaining sites. We’ve taken some of the most frequently asked questions about our work to safely close ash basins and answered them in this blog post. Here are the top five things you need to know about Duke Energy’s coal ash management efforts.

1. HOW DOES DUKE ENERGY DEVELOP ITS BASIN CLOSURE PLANS?

No two ash basins are alike, and each one needs a custom solution. To ensure that all closure plans meet high standards the team developed guiding principles that comply with applicable laws and shape our decisions. The guiding principles include things like:

  • Protecting groundwater – Any closure plan must protect groundwater. To understand what’s happening under our facilities, we installed more than 900 new groundwater monitoring wells and completed comprehensive assessments of each of the 14 coal plants in North Carolina. Next, we’ll complete modeling to understand how groundwater may change under different closure scenarios.   
  • Safe ash recycling – We are committed to safely recycling coal ash when possible, and we are always looking for new and innovative ways to use the material. In 2014, we recycled nearly half of all the coal ash we produced. For example, ash is being used in construction materials like concrete and in structural fills, turning open-pit clay mines into usable land.
  • Minimizing impacts to local communities – We look for ways to avoid transporting ash away from our property. In cases where we do have to move the ash off-site, we take extra precautions to safely transport the material. Trucks are covered and washed clean before leaving a site and rail transport is used when it is available.


2. HOW DO YOU ACTUALLY CLOSE AN ASH BASIN?

There are a number of ways that you can safely close an ash basin once the water is removed.

  • The ash can also be stored in a lined landfill composed of a network of natural and synthetic liners. Once it’s filled, it is sealed with a synthetic barrier and gets a layer of protective soil and vegetation on top. Additional groundwater monitoring wells are installed to monitor conditions for many years.
This diagram shows how coal ash can be safely stored with a fully lined landfill.
This diagram shows how coal ash can be safely stored with a fully lined landfill.

 

  • Another option to safely close basins is to consolidate the ash on-site and cap it with an engineered synthetic barrier. In these situations, the ash within the basin is covered with a durable synthetic cover system to keep rain and water out. The liners are heat sealed together and layers of soil and vegetation are placed on top. Capping basins on-site is acommon closure method and is a preferred approach in federal coal ash regulations.
This diagram shows how coal ash can be safely stored with an engineered capping system.
This diagram shows how coal ash can be safely stored with an engineered capping system.


3. WOULD DUKE ENERGY CONSIDER LEAVING ASH ON-SITE AT SOME PLANTS?

Keeping the ash on our property avoids disruption to neighboring communities with increased truck traffic and other environmental impacts. In addition to being a more economically responsible solution, this approach can allow a utility to safely close an ash basin much quicker than relocating all the material to a new facility that needs to be sited, permitted and built. 

Most importantly, consolidating and capping basins on-site would only be done if science and engineering information demonstrate that groundwater can be protected over the long term.


4. HOW ARE YOU MANAGING ENVIRONMENTAL IMPACTS WHILE TRANSPORTING ASH?

We’ve partnered with some of the leading vendors in the industry to develop transportation plans that include a variety of measures that minimize dusting, both on and off each site. These include tight-fitting truck covers, wash stations to clean trucks before they exit a site, observing speed limits, as well as other industry best practices.

No matter the closure approach, Duke Energy remains committed to closing ash basins with solutions that are smart and safe for the communities we serve.


5. WHAT IS THE IMPACT OF BASIN CLOSURES ON CUSTOMER RATES?

We’ll learn more about this over time as part of a public rate adjustment process. Historically, the cost to build, operate and retire power plants are built into the rates our customers pay. At some point in the future, we will ask utility commissioners to determine if coal ash basin closure costs should be added to our customer rates.

Track our ash management progress online. 

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