Union Electric 

Operating commercially as Ameren Missouri, Union Electric Company functions as a regulated utility, primarily engaged in the generation, transmission, and distribution of electricity across Missouri. The firm sources its power from a varied portfolio of energy types, including coal, nuclear, natural gas, hydroelectric, methane gas, and solar installations. Furthermore, it manages a regulated system for natural gas distribution. The company delivers electrical services to approximately 1.2 million customers and natural gas services to around 100,000 customers, covering a significant 24,000 square-mile territory in central and eastern Missouri. Established in 1881, its corporate offices are situated in St. Louis, Missouri, and it operates as a subsidiary of Ameren Corporation.