Union Electric 

Operating as Ameren Missouri, Union Electric Company is a utility enterprise based in Missouri, primarily involved in the regulated generation, transmission, and delivery of electricity. The company utilizes a diverse array of energy sources for its power production, including coal, nuclear, natural gas, hydroelectric, methane gas, and solar. Beyond electricity, it also manages a regulated system for natural gas distribution. Ameren Missouri provides electrical service to approximately 1.2 million households and businesses, and natural gas to 100,000 customers, across a vast 24,000 square-mile expanse covering central and eastern parts of the state. Founded in 1881, its main offices are located in St. Louis, Missouri, and it operates as a subsidiary of Ameren Corporation.