William H. Zimmer Power Station
| Company type | Power station |
|---|---|
| Industry | Energy |
| Predecessor | Cincinnati Gas and Electric (CG&E), Columbus & Southern Ohio Electric, Dayton Power & Light (DP&L) |
| Founded | 1972 |
| Defunct | 2022-05-31 |
| Headquarters | Moscow , United States |
Area served | Ohio, United States |
| Products | Electricity generation (coal-fired) |
| Owner | Vistra Corp (2018–2022) |
William H. Zimmer Power Station, situated close to Moscow, Ohio, was a 1.35-gigawatt (1,351 MW) facility fueled by coal. Originally envisioned by Cincinnati Gas and Electric (CG&E), a predecessor of Duke Energy, in partnership with Columbus & Southern Ohio Electric (which later became part of American Electric Power (AEP)) and Dayton Power & Light (DP&L), the project was initially designed as a nuclear power plant. Despite reaching nearly 97% completion, construction flaws and quality control problems necessitated its conversion into a coal-fired plant. Operations commenced in 1991. Ownership transferred to Vistra Corp in 2018, which managed the plant until its shutdown on May 31, 2022.
Construction
The Zimmer facility originated as a collaborative effort between CG&E, Columbus & Southern Ohio Electric, and DP&L, announced in 1969 with an estimated $420 million budget for two nuclear units rated at 840 MW each, planned for completion in 1975 and 1976. Named in honor of William H. Zimmer, former chairman and president of CG&E, construction began in 1972 after the Atomic Energy Commission introduced more rigorous regulations. In 1974, the planned capacity for the second unit was increased to 1,170 MW with General Electric boiling water reactors selected; however, this second unit was ultimately never constructed due to regulatory challenges and escalating costs.
By 1978, inspections uncovered welding deficiencies that failed to meet nuclear safety criteria. CG&E attributed these issues to contractor oversight lapses. In 1980, accusations emerged regarding CG&E’s concealment of falsified time records and improper installation of piping within critical safety systems. The Nuclear Regulatory Commission penalized CG&E $200,000 in 1981 for inadequate quality assurance practices. Construction was overseen by The Henry J. Kaiser Company, while CG&E retained responsibility for procurement and quality controls.
Following pressure from the Government Accountability Project, the NRC suspended reactor construction activities in 1982. Concurrently, the FBI launched investigations into irregularities involving safety documentation and harassment of inspectors.
In 1983, after incurring $1.6 billion in expenditures—CG&E’s share constituting nearly 90% of its net worth at the time—the consortium comprising CG&E, AEP, and DP&L abandoned the Zimmer nuclear project. Retired Navy Admiral Joe Williams Jr. was brought on board to explore options for completing the plant, and Bechtel was contracted to bring the facility up to nuclear standards; nevertheless, Bechtel estimated that an additional investment exceeding $1.5 billion would be necessary to finalize construction satisfactorily.
Conversion to Coal
Originally projected to cost $240 million for a single unit, expenses ballooned beyond $3.1 billion, leading to a January 1984 decision to repurpose the idle plant as a coal-fired power station. In July 1984, the three utility companies filed suit against architect/engineering firm Sargent & Lundy and General Electric seeking $400 million in damages related to defective equipment that had inflated construction costs. The dispute concluded with a November 1987 settlement wherein Sargent & Lundy paid $27.4 million while the utilities contributed $12.7 million.
The conversion process commenced in March 1987 and incorporated environmental safeguards such as diverting Little Indian Creek through the plant area to safeguard aquatic life and relocating mussel populations upstream. After total expenditures reached $3.3 billion, this pioneering nuclear-to-coal power station was completed in 1991.
On March 2, 2012, a tornado struck the Zimmer site causing damage to structures and electrical towers; no injuries were reported and electricity production continued throughout repair efforts.
Duke Energy divested its interest in Zimmer to Dynegy in 2014. Subsequently, AEP traded its 25% ownership stake for Dynegy’s share in Conesville Power Plant in February 2017. By April of that year, Dynegy acquired DP&L’s remaining 28% shareholding, becoming sole proprietor of Zimmer. Following Dynegy’s merger with Vistra Energy in 2018, ownership transferred accordingly.
In March 2020, Vistra Energy reached a settlement with the EPA addressing two decades of emission violations at Zimmer; this included paying a $600,000 fine through the Department of Justice, upgrading energy-efficient lighting at a nearby school facility, and replacing three school buses with models featuring cleaner-burning engines.
Retirement
Vistra initially revealed in September 2020 its plan to decommission the Zimmer facility by the end of 2027. However, on July 19, 2021, the company moved the closure date forward to May 31, 2022, due to an inability to obtain capacity revenues during the May 2021 PJM Interconnection wholesale electricity market auction. Consequently, the Zimmer coal-fired power station ceased operations on May 31, 2022.
Equipment
Zimmer utilized components from its former nuclear installation combined with technology adapted for coal conversion. The original Westinghouse turbine, featuring both high-pressure and low-pressure sections, was altered by removing the high-pressure segment. The General Electric reactor was initially engineered to produce 840 MW. ASEA Brown Boveri (ABB) was responsible for designing the high-pressure turbine, intermediate-pressure/reheat turbine, and generator units. The HP/IP generator delivers 900 MW, whereas the Westinghouse LP generator provides 497 MW. The feedwater pump operates via a turbine mechanism, generating roughly 67,000 horsepower.
The boiler, crafted by Babcock & Wilcox, functions as a supercritical steam generator with operating conditions near 3,845 psi and temperatures around 1,010°F, including a reheat section at approximately 1,000°F. Environmental mitigation systems feature selective catalytic reduction (SCR) technology to lower nitrogen oxide (NOx) emissions, electrostatic precipitators for fly ash extraction, and a flue-gas desulfurization (FGD) unit capable of removing up to 98% of sulfur dioxide (SO2). The gypsum produced as a byproduct from the FGD process is marketed for use in drywall production.
Originally designed to support nuclear plant cooling demands, the cooling tower’s capacity limited performance during peak summer heat due to elevated operational loads. Additionally, a 573-foot tall smokestack was erected to facilitate flue gas discharge.
See also
- Beckjord Power Station
- List of power stations in Ohio
- List of canceled nuclear plants in the United States
External links
- Articles with short description
- Energy infrastructure completed in 1991
- Buildings and structures in Clermont County, Ohio
- Former coal-fired power stations in Ohio
- Cancelled nuclear power stations in the United States
- 1991 establishments in Ohio
- 2022 disestablishments in Ohio
- Nuclear power plants in Ohio
- Vistra Corp