Closing Coal Ash Basins Protects Customers, Environment

A roughly two-year-long project will result in the closure of Ameren Missouri’s coal ash basins as the company implements a plan touted for its commitment to customers and the environment. 

"Safe, responsible closure of Ameren Missouri's coal ash basins demonstrates an ongoing commitment to customers and the environment," said Craig Giesmann, senior manager for Environmental Services at Ameren Missouri. "We are implementing a proactive comprehensive plan to safely and responsibly close our basins, the storage facilities that hold the byproducts of generating electricity from coal." 

Under the plan, the ash will be compacted, graded, and sloped to permanently shed water. An engineered capping system – far stronger than regulations require – will be constructed over the top of the basins and the river-side embankment walls armored with rock. Precipitation will be routed to newly constructed stormwater basins. The limited groundwater impacts localized to the property will diminish over time, and experts are evaluating methods to accelerate this process. This system, implemented at each of Ameren Missouri's four fossil energy centers (coal plants), will take approximately two years to construct and will isolate the ash from infiltration. 

A 2015 federal rule, implemented under the Obama Administration, requires Ameren Missouri to close these basins and address impacts to groundwater. 

As confirmed by independent, third-party experts, Ameren Missouri’s basins do not impact drinking water sources, including residential wells that rely on groundwater or nearby rivers that serve both municipal and public water supplies, and modeling confirms they will not be impacted in the future. 

The Safe, Responsible Closure in Place plan is touted as: the most efficient path to achieving the groundwater protection standards set under the federal rule; protecting the environment because, as verified by third-party structural engineers, the basins are built to withstand extreme events such as floods and earthquakes; limiting the burden on the communities Ameren Missouri serves; and fully complying with applicable state and federal requirements. 

After the basins are closed, Ameren Missouri will continue to monitor water resources near each of the facilities for years to come, and will inspect the basins to ensure structural integrity and perform regular maintenance to prevent erosion.