Ameren Missouri takes next step to support reliable energy for customers

Key Takeaways:

• Ameren Missouri is taking action to strengthen electric reliability by advancing five Missouri-based projects designed to deliver more energy when it's needed most.
• The approved projects include 545 megawatts (MW) of battery storage that adds fast-acting flexibility to the grid.
• The projects are a cost-effective way to optimize investments by leveraging competitive bidding, existing infrastructure, and available transmission capacity.

ST. LOUIS (Oct. 21, 2026) - Ameren Missouri is building a stronger, more resilient energy grid for customers by adding facilities that can help meet their needs during periods of high use, including extreme temperatures. Today the Missouri Public Service Commission (MoPSC) approved Ameren Missouri's plans to build the Castle Bluff, Huck Finn and Millcreek battery energy storage systems and acquire the Ringer and Tom Sawyer solar developments. Together, these Missouri-based projects are designed to generate electricity or store energy and deliver it to the grid when customers need it most, including during extreme heat, cold and other times of high energy use.

"Deploying these projects now helps prepare the grid for how our customers will use energy in the years ahead," said Ajay Arora, executive vice president and chief growth and generation development officer for Ameren Missouri. "Battery storage can respond within moments to changing grid conditions and provide additional energy when demand is highest."

Projects approved today include:

• Castle Bluff, a 95-MW battery storage project co-located at the Castle Bluff Energy Center, currently under construction in St. Louis County with a targeted in-service date of 2028.
• Huck Finn, a 200-MW battery storage project located near the Huck Finn Renewable Energy Center in Audrain County with a targeted in-service date of 2028.
• Millcreek, a 250-MW battery storage project in Lincoln County with a targeted in-service date of 2028.
• Ringer, a 225-MW solar facility based in Stoddard County with a targeted in-service date of 2029. Ameren Missouri will acquire the facility from Invenergy. It will produce enough energy to power more than 40,000 homes a year.
• Tom Sawyer, a 175-MW solar facility based in Audrain County with a targeted in-service date of 2028. Ameren Missouri will acquire the facility from EDF power solutions. It will produce enough energy to power more than 31,500 homes a year.

The MoPSC's review included input from residents, local officials and others.

"We appreciate the participation of community members and stakeholders throughout the review process, and we're focused on delivering projects that support safe and reliable service for our customers," said Rob Dixon, vice president of regulatory, legislative and external affairs for Ameren Missouri.

About Ameren Missouri
Ameren Missouri has been providing electric and gas service for more than 100 years, and the company's electric rates are among the lowest in the nation. Ameren Missouri's mission is to power the quality of life for its approximately 1.3 million electric and 135,000 natural gas customers in central and eastern Missouri. The company's service area covers approximately 60 counties and more than 500 communities, including the greater St. Louis area. For more information, visit Ameren.com/Missouri or follow us at @AmerenMissouri or Facebook.com/AmerenMissouri.