Ameren Plans 2,100-Megawatt West Alton Gas Plant

Missouri regulators will hold two public hearings on Ameren Missouri's proposed natural gas power plant in St. Charles County.

Updated on Nov. 10, 2026 in Utilities

Bold flat-color editorial illustration of tall gas-turbine stacks and steel transmission towers rising across open farmland, with cables converging toward the horizon. — Ameren Missouri proposed a 2,100-megawatt West Alton natural gas plant in St. Charles County, with Missouri regulators holding public hearings starting Nov. 18. AI Illustration. Upload story photo >

Live Poll

Should Missouri approve new natural gas power plants to meet rising electricity demand?

Ameren Missouri proposes a 2,100-megawatt natural gas plant, the West Alton Energy Center, in St. Charles County, and the Missouri Public Service Commission will hold public hearings on the project starting Nov. 18. Ameren has asked the commission for approval by early spring 2027.

Why it matters

Ameren says the plant would help meet growing electricity demand across its service area, which is prompting the utility to pursue some projects sooner. Residents and ratepayers in Missouri could be affected by how the commission weighs project costs that Ameren has not yet publicly quantified.

The proposed plant would have 2,100 megawatts of capacity across three generating units, with Ameren estimating more than 1,000 construction jobs over several years and about 45 permanent jobs after opening. Ameren has not released an exact construction cost, and the commission will decide which costs may be recovered during construction.

The players

Ameren Missouri

Ameren Missouri is the electric utility serving much of Missouri and is the company proposing the West Alton Energy Center.

Missouri Public Service Commission

The Missouri Public Service Commission is the state regulatory body that will hold hearings and decide whether to approve the West Alton project.

The details

The plant would be built next to Ameren's Sioux Energy Center on land Ameren already owns and would connect to the grid using existing nearby transmission infrastructure. It would generate electricity when wind and solar output drops.

Nov. 18: First public hearing at 6 p.m. at St. Charles Community College in Cottleville.
Nov. 19: Virtual public hearing at 6 p.m.
Early spring 2027: Ameren requested commission approval of the project.
April 2027: Commission evidentiary hearing scheduled.
2031: West Alton plant planned to begin operating.

Roadmap

The West Alton proposal follows Ameren's plan to retire its aging Sioux plant by the end of 2035, with the new gas plant built beside it. The project enters the Missouri Public Service Commission's review process, where the commission will decide how costs may be recovered during construction.

Ratepayers may see the cost of this plant reflected in their electricity bills depending on how the commission rules on recoverable construction costs. Residents near the site in St. Charles County may also notice construction activity over several years.

The takeaway

Missouri residents who want to weigh in on the West Alton plant can attend the public hearings scheduled for Nov. 18 and Nov. 19 before the commission considers the project.

What happens next

The first public hearing is set for Nov. 18 at St. Charles Community College, followed by a virtual hearing on Nov. 19, with a commission evidentiary hearing scheduled for April 2027.