Osage Dam
Osage Dam — better known as Bagnell Dam, home to Ameren Missouri's Osage Energy Center — is a conventional hydroelectric plant on the Osage River in Miller County, Missouri, that impounds the river to create Lake of the Ozarks. Eight generating units give the plant 208 MW of EIA nameplate capacity and about 234 MW of net summer capacity, and all eight are currently operating with no retirement scheduled. The plant is owned and operated by Union Electric Company, doing business as Ameren Missouri, a subsidiary of Ameren Corporation, and it sells into the MISO market. It has run continuously since going into service in 1931, and FERC granted Ameren a new 40-year operating license for the Osage Project (No. 459) in March 2007, keeping the facility licensed into the late 2040s. Ameren has been steadily modernizing the powerhouse, including a $52 million dam-stabilization project finished in 2018 and, in 2025, the replacement of the last two original 1933 turbines, capping a turbine-upgrade program that has raised the plant's output over the past two decades.