How TVA Is Storing Its Ash

To get the “low-down” on what TVA is doing with its coal ash, we caught up with John Kammeyer, TVA vice president Civil Projects. Kammeyer leads the TVA team tasked with safely closing the company’s coal ash impoundments.

The strong, weathered hand of Tom Morrow, retired TVA shift supervisor (41 years of service), hovers over the button waiting for the command to shut down the Colbert Fossil Plant. In the somber control room, TVA unit operator Dennis Skipworth scans his control panel one last time and then gives the command to Morrow. At that moment Morrow presses the button; ending the plant’s 61-year legacy of electrical generation.

Scenes like this are playing out across the Tennessee Valley as TVA closes fossil plants to keep the Valley’s air quality better than it has ever been measured and upgrade the company’s electrical generating fleet to more efficient gas combined-cycle technology.

John Kammeyer, TVA Vice President Civil Projects, leads TVA’s team tasked to safely close existing coal ash ponds and develop a new way to safely store ash at the company’s remaining fossil plants.

“Coal-fired plants were the backbone of our power system since TVA first started using them in the 1950s,” says Kammeyer. “As TVA invests in a greener future—achieving a 61% carbon-free energy mix by 2026—our work at our fossil plants is not done. We must focus our efforts on safely storing decades of ash to protect the environment that we are working so hard to keep clean.”

Kammeyer explains that his team receives many coal ash closure questions. Here, he answers some of the most commonly asked.

What is coal ash?

When we burn coal, ash and other by-products called coal combustion residuals (CCRs) are created. TVA recycles 33 percent of its CCRs; they go into common building materials like concrete, roof shingles and wallboard. CCRs that cannot be recycled are removed from boilers and other equipment and currently are stored on site.

What do industry opinion leaders say about TVA’s methods of storing coal ash?

The EPA concurs with TVA’s preferred method to close 10 of our ash impoundments in place announced in June 2016. Moving forward, TVA is the industry leader in dry ash storage technology. TVA is the only utility in the world pioneering intelligent compaction technology to safely store dry coal ash – which turns dry powered ash into a rock-hard substance. TVA managers are telling our story to technical societies and organizations such as the United States Society of Dams and the Electric Power Research Institute, as well power company engineers at Duke and Southern to showcase our innovative technology, which helps protect the environment. Additionally, TVA’s innovative methods can be seen on TV and in respected publications such as Coal World, Coal Age and Energy Wire.

How do you “close” the ash impoundment/cell/pond/facility?

Closing a dry ash or wet ash pond is a complicated process that requires a lot of science, engineering and continual testing. Plus there are Federal reviews/approvals that must occur before starting work.

To put it simply, closing an ash pond or dry ash stack means covering it in a very careful way to prevent water from entering the ash. TVA is using the following closure method as seen in the illustration below. The geomembrane is a strong plastic cap that is welded together to prevent water from penetrating into the ash. Then we place a drainage net over the geomembrane so water can run off. To protect the geomembrane and net, soil is layered on with grass planted on top.

When the process is completed the closed structure looks like a lush green park.

What happens after the ash is capped?

TVA will monitor the ash facilities for 30 years. TVA’s closure method is approved by the EPA and follows the CCR and state guidelines. Actually, TVA exceeds these strict Federal rules having already installed over 7,000 real-time sensors to monitor our impoundments. Every five minutes, sensors send data to a centralized computer monitoring system within TVA. Our continuous ash pond monitoring will ensure the public and environment remains safe.

How do you know the ash is not affecting groundwater?

Continual testing. For more than 30 years we have been monitoring the biologic and ecologic health of the Tennessee River basin. For the next 30 years we will monitor and test groundwater at our facilities to ensure that the ash does not affect groundwater. Each state requires TVA to test groundwater and share that data with the appropriate state agency that regulates environmental issues.

To comply with the EPA Coal Combustion Residuals (CCR) Rule we established a groundwater sampling and analysis program and installed new wells to gather more data. The first year of monitoring will require eight background sampling events across the Valley at the facilities to capture baseline data. Once the background data has been established for these wells, groundwater monitoring will continue on a semi-annual basis, with a yearly report being posted to TVA’s CCR Website.

CCR Rule Compliance Data and Information

In April 2015, the Environmental Protection Agency (EPA) passed regulations that govern the disposal of coal ash (coal combustion residuals or CCRs) that isn't recycled and reused. The CCR Rule establishes technical requirements for CCR landfills and surface impoundments under subtitle D of the Resource Conservation and Recovery Act. Learn more about how TVA is satisfying CCR requirements.

The Advanced Technology for Impoundment Monitoring Center

TVA monitors its coal ash 24/7/365 to ensure that there are no safety or environmental issues. To that end, it has developed the new Advanced Technology for Impoundment Monitoring (ATIM) center in Chattanooga to immediately identify and respond to any coal ash issues before any emergency could happen. Read more about the ATIM