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Water Management

Ameren is committed to protecting our natural resources, including reducing our water use and returning clean water to our environment. Our water management approach includes conscious decisions to conserve water in how we design and modify our facilities, as well as minimize impact on water ecosystems and habitats. We also have processes in place to protect groundwater and other freshwater sources in the regions where we operate.

Ameren regularly evaluates water-related issues as part of the overall business strategy and long-term financial planning. We recently conducted a Water Resiliency Assessment that assessed the current and future availability of water resources and potential water stress in our regions of operation and key portions of our supply chain. This information is helping us better plan for our businesses’ future water needs.

One major step we are taking is to reduce the use of surface water by 11 billion gallons a year by converting to dry ash handling systems at the coal-fired energy centers. The planned retirements of our coal-fired facilities and increased investments in water efficiency measures will enable us to conserve even more water in the future.

Ameren’s water management approach is driven by the Clean Water Act and we are currently developing a more robust water policy to further guide our approach.

Water Management At-a-Glance

More than 70 million megaliters of water withdrawn in 2019, and nearly all of it discharged back to the environment

More than 35,000 megaliters of water consumed in 2019

Water intensity average of 0.83 cubic meters (m3) per MWh of net generation in 2019

Water Policy

Ameren is committed to protecting our natural resources, including reducing our water use and returning clean water to our environment. Water is a shared resource and we strive to uphold environmental standards and reduce our reliance on this critical resource in order to protect it for future generations.

Though our facilities are geographically situated in an area of ample water supply, we understand the implications of climate change on water stress. We rely on large quantities of fresh surface water from local rivers for power generation at our hydroelectric energy centers, as well as for cooling purposes at our coal and nuclear fueled energy centers. Consistent with our regulatory obligations, we strive to minimize impact on water ecosystems and habitats. Almost all of the water we withdraw for operations is returned back to the environment from where it came, and only a small fraction of water is evaporated during these processes. Water we discharge back to the environment complies with environmental permitting requirements and we plan to significantly reduce our use of water as we transition to increased low and no-carbon generation, primarily through the retirement of our coal-fired energy centers.

We will implement this policy through the following actions:

  • Assess water resource resiliency to understand how climate change may affect water resources and consistent water availability.
  • Reduce water use in accordance with our water reduction targets.
  • Track and publicly report on water use in our generation operations
  • Consider water management practices in our planning and decision making processes and identify improvement opportunities, such as implementing water conservation and efficiency technologies in our facilities, where feasible.
  • Provide co-workers adequate access to water, sanitation, and hygiene facilities in the workplace.
  • Engage with stakeholders on water-related issues, including government and businesses when feasible.
  • Comply with applicable laws and regulations and monitor impacts to water quality from operations in accordance with Ameren's Environmental Policy.
  • Periodically review and update the Water Policy.

Managing Our Water Use

Freshwater from the Mississippi and Missouri Rivers is used for thermal cooling at our major nuclear and fossil fuel energy centers and for energy production at our hydroelectric generation sites. After the water is used, we treat it in our wastewater treatment systems. The clean water is closely monitored for quality well within our permit limits, then discharged to local rivers or third-party sources. Approximately 99% of water withdrawn is discharged back to the environment. In addition, upgrades we are making to the wastewater treatment systems at three coal-fired energy centers are projected to save 230 million gallons of water annually starting in 2023.

Recycled water is used at several of our facilities. For example, the Taum Sauk Energy Center features a closed-loop system that continuously reuses water. We are considering ways in which we can use more recycled water than freshwater in the future. The upcoming retirement of our coal-fired energy centers also will dramatically reduce our freshwater use and water intensity.

We often receive questions about water in relation to the coal ash basins that hold coal combustion residuals (CCRs), waste product left over at our coal-fired energy centers. Since 2012, Ameren Missouri has demonstrated that our CCR management and disposal activities do not pose an adverse risk to public health and the environment, including water. Coal ash basins are permitted by Missouri Department of Natural Resources and all discharges are closely monitored and reported to the state. Ongoing off-site sampling adjacent to our energy centers confirms that surface waters that serve as a public water supply resource comply with drinking water standards. We know this topic has raised questions in our communities, so in 2019 we held public meetings near each of our coal-fired energy centers to listen to community members’ concerns and provide accurate information.


Harnessing Water for Energy

Water also serves as one of Ameren’s energy-generating sources. Hydroelectric power is a form of clean energy, which helps to contribute to Ameren’s goal to achieve net-zero carbon emissions by 2050. Ameren Missouri operates three hydroelectric energy centers that harness freshwater and pumped water to create power: Keokuk Renewable Energy Center on the Mississippi River, Osage Energy Center at the Lake of the Ozarks’ Bagnell Dam and Taum Sauk pumped storage facility. Water releases from these facilities are monitored and managed to meet regulatory criteria.

Read more about Ameren’s water management efforts in our annual CDP Water Security Questionnaire in our ESG library.

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