Smart Energy Plan

November 14, 2025

Bulk Substation Upgrades Bolster Reliability in St. Louis Area

Critical infrastructure improvements support more than 100,000 customers

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Bulk substations convert energy from high-powered transmission lines to levels suitable for local distribution. These facilities can supply power to tens of thousands of customers, making them crucial to reliable energy delivery. Through the Smart Energy Plan, Ameren Missouri is upgrading some of its oldest bulk substations to improve safety and support reliability for our customers.

In Wellston, crews are close to completing a comprehensive, multi-year modernization of the Page bulk substation. This facility supports more than 45,000 customers in the St. Louis region, from downtown Clayton to Lambert-St. Louis International Airport.

The Page project includes upgrading several of the substation transformers, replacing older equipment that has reached the end of its useful life. The new transformers have additional capacity, which is essential for maintaining reliability during times of peak demand and creating flexibility to reroute power during storms.

“We closely monitor the condition of our substations and assess how each component impacts reliability for our customers,” said Joe Fitzgerald, director of substation maintenance and construction for Ameren Missouri. “Not only were these transformers showing their age, but they just weren’t equipped to handle the needs of a modern electric grid.”

Additional upgrades to support these new transformers were completed in 2025. Crews removed old control wiring and upgraded first-generation relays with modern units. The replacement control house has also been redesigned to have more space for crews to work safely on the equipment.

In Bellefontaine Neighbors, Ameren Missouri has upgraded several transformers at its Maline bulk substation. The existing transformers were susceptible to failures during storms or other abnormal situations. These new transformers are built with increased mechanical strength to resolve these issues, and they also incorporate upgraded voltage regulation technology that provides reliable service even during times of peak loads.

Improvements to the Maline bulk substation support greater reliability for the more than 60,000 customers served by this facility. This includes customers across a large portion of north St. Louis County, from Florissant to Spanish Lake, as well as industrial customers along the north riverfront in the city of St. Louis.

“When you look ‘downstream’ of these substations, you get a better sense of the true impact of these upgrades,” Fitzgerald said. “The improvements to these substations benefit everyone in the community, from renters and homeowners to schools and hospitals to major manufacturers looking to invest and expand in the St. Louis region.”

The latest phase of upgrades to the Maline and Page bulk substations was completed in 2025. To learn more about how the Smart Energy Plan is supporting reliability in Missouri, visit Ameren.com/Reliability.