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Smart Basin Closure

Closing Ash Basins

Safely. Quickly. Permanently.

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Closing Ash Basins the Smart Way

Delivering on our commitment to quickly and safely close all our coal ash basins

What Is Coal Ash – and Why Should You Care?

Like the ash in your fireplace, coal ash is left behind when we burn coal to generate the electricity you rely on. Historically, the energy industry standard was to store ash in engineered filtration ponds – ash basins – and there are hundreds across the nation today.

At Duke Energy, we're closing all our ash basins – we've already excavated 20 million tons of ash in North Carolina alone. And in just a few months, upgraded technology at our plants will replace ash basins altogether.

Infographic: Closing All of North Carolina's Ash Basins

In fact, we're likely doing more in terms of speed, scope and scale than any other utility in the nation to complete this work. We are also building renewable energy sources, have retired our oldest coal plants, and are converting others to dual-fuel operation with cleaner, more cost-efficient gas – helping us achieve a 70 percent reduction over the last decade in the amount of ash produced, even while generating more power for a growing region. 

Smart, Safe, Customized Solutions

We're building three new recycling units to process our ash, turning this byproduct into a useful construction resource. Once they're online, we'll reuse more ash than we produce each year. But recycling all the ash stored over many decades isn't feasible, so what happens to the rest?

The U.S. Environmental Protection Agency says basin closure plans must protect the environment, and they've approved two main ways to safely close a basin: cap the ash in place, or excavate the material and transport it to a new location. We're doing both – 22 smaller basins are being excavated, while we recommend capping the nine largest – applying science and engineering to drive custom solutions for each plant.

Why Not Excavate Everywhere?

Some say excavation should be the only option, but their one-size-fits-all approach could actually do more harm than good. After extensive studies at each of our sites, experts concluded capping the ash in place is the best closure method for basins at several of our plants.  In some cases, the material could be consolidated into a smaller area and then capped.

At sites where tests show both excavation and capping produce similar results, here's why capping can make more sense:

  • Insulates communities by drastically reducing the length of disruption caused by excavation
  • Faster closure compared to excavation, which could take more than 30 years in some cases
  • Less expensive for customers than excavation while equally protective of the environment

Guarding Your Water and Your Wallet

State lab tests, independent studies and thousands of monitoring wells prove drinking and recreational water are well-protected from ash; we'll monitor for decades to ensure that remains the case. And the most effective step to improve groundwater quality is to safely remove the free water from the ash basin – which we will do at both excavated and capped basins.

We've heard your concerns and assure you customers will never pay cleanup costs associated with the Dan River ash spill in 2014 – that's our responsibility.

Separately, state regulators determined that customer rates should include the cost of closing basins and upgrading to better technologies because this work complies with state and federal laws.  So, we’re keenly focused on delivering cost-effective results.  

We're committed to getting this right for you, investing in real solutions that are grounded in science to protect you in a safe, smart, responsible way. We're doing what's right today for a better tomorrow.

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