History
Origins: Nuclear Ambitions
The W.H. Zimmer site, located along the Ohio River near Moscow, Ohio (about 25–30 miles southeast of Cincinnati), was originally conceived as a large nuclear power plant to meet growing regional electricity demand.
In 1969, Cincinnati Gas & Electric (CG&E), along with partners Columbus & Southern Ohio Electric and Dayton Power & Light, announced plans for the project.
The original plan called for two boiling water reactor (BWR) nuclear units. Construction began in 1972.
The plant was named after William H. Zimmer, former chairman and president of CG&E.
1969–early 1970s
Construction Challenges
As construction progressed, the project encountered technical, regulatory, and management issues.
In 1983–1984, the utility consortium made the decision to abandon the nuclear project entirely.
Regulators were formally notified in January 1984 that the nuclear license application would be withdrawn, and the site would no longer be used for nuclear generation.
Mid 1970s–early 1980s
Conversion to Coal: A Unique Pivot
Rather than scrap the nearly completed facility, the owners made a highly unusual decision:
In 1984, they chose to convert the partially built nuclear plant into a coal‑fueled power station.
The redesign reused portions of the existing infrastructure (e.g., turbine equipment and site layout) but replaced the reactor with a supercritical coal boiler system.
This project became widely recognized as the first—and essentially only—example of a nuclear power plant being converted into a coal plant at such an advanced stage of completion.
Mid 1980s–early 1991
Commercial Operation as a Coal Plant
The facility entered service as the William H. Zimmer Power Station in:
1991, with a capacity of roughly 1,300–1,400 MW, making it one of the largest single-unit coal plants in the United States.
For decades, the plant:
Supplied baseload power to the regional grid
Operated under evolving ownership structures tied to Midwest utility consolidations
Became a major industrial presence and employer in Clermont County
Contributed significantly to the local tax base and economy
Eventually, ownership consolidated under Dynegy and later transferred to Vistra Corp., which acquired the plant in 2018.
1991–2022
Plant Closure
In the 2010s and early 2020s, the plant faced increasing challenges:
Rising competition from natural gas and renewables
Higher operating and compliance costs associated with coal generation
Market conditions that made the plant less economically viable
The company ultimately retired the plant on May 31, 2022.
2022