Conesville Power Plant

Conesville Power Plant

Company type	Coal-fired power plant (former)
Industry	Energy
Founded	1957
Defunct	April 2020
Headquarters	Conesville, Ohio , United States
Area served	Ohio
Products	Electricity generation
Owner	American Electric Power (AEP), AES Ohio Generation, DP&L (minority share in Unit 4)
Number of employees	165 (2018)

Conesville Power Plant was a coal-powered facility with a generation capacity of 2,005 MW, situated near Conesville, Ohio within Coshocton County, Ohio. At the time of its shutdown, ownership was shared between American Electric Power (AEP) and AES Ohio Generation, with AEP overseeing all operational activities. The plant commenced its service in 1957 and discontinued power production in April 2020.

History

The plant’s construction began in 1955 under Columbus & Southern Ohio Electric, which later became part of AEP. Commercial operations started with Unit 1 in 1957, followed by Unit 2 in 1959; each unit had a capacity of 125 MW and together represented an investment of $36 million. Unit 3 was added in 1962, offering 165 MW output. Unit 4 came online in 1973 with a capacity of 780 MW and was initially co-owned by Cincinnati Gas and Electric (CG&E), Columbus & Southern Ohio Electric, and DP&L. The final two units, Units 5 and 6, began functioning in 1976 and 1978 respectively, gradually increasing their combined capacity from 375 MW to 405 MW.

In 2014, Duke Energy divested its stake to Dynegy, which subsequently exchanged its ownership share with AEP in 2017 for an interest in the William H. Zimmer Power Station. At the time of shutdown, DP&L maintained a minority shareholding in Unit 4 alongside AEP.

Environmental mitigation

The addition of Unit 4 included the implementation of electrostatic precipitators (ESPs) to control fly ash emissions. ESPs were subsequently installed on Units 1 through 3 during the mid-1970s. Unit 4 also utilized cooling towers designed to eliminate discharge into the Muskingum River. In 2009, a $450 million retrofit equipped Unit 4 with advanced flue-gas desulfurization (FGD) and selective catalytic reduction (SCR) technologies to meet EPA mandates under the Clean Air Interstate Rule (CAIR) and Clean Air Mercury Rule (CAMR). This upgrade involved constructing a new smokestack for the FGD system. Following installation, corrosion problems arose, leading AEP to reach a settlement with contractor Black & Veatch to rectify the defects.

When Units 5 and 6 were commissioned, $52 million was allocated for installing scrubber systems aimed at lowering sulfur dioxide () emissions; however, initial performance was suboptimal until improvements were made in 2008. In 2001, Unit 6 trialed Thermal Energy International's THERMALONOx technology intended to reduce nitrogen oxide () emissions by approximately 70%, but the test was discontinued after failing to produce substantial emission reductions.

Operations

Originally, Conesville was expected to consume between 300,000 and 400,000 short tons of coal yearly. By 2017, the facility received over 1.7 million short tons of coal exclusively mined within Ohio. Workforce numbers decreased significantly from around 600 employees to approximately 165 by the year 2018.

Retirement

Units 1 and 2 were decommissioned in 2005 due to extensive boiler tube failures and severe corrosion issues; repair costs estimated at $35 million were considered financially impractical. Unit 3 ceased operations in December 2012 to adhere to EPA regulations targeting mercury, lead, and other hazardous pollutants. In October 2018, AEP declared plans to shut down the plant by May 2020. Units 5 and 6 were retired in May 2019 while Unit 4 continued until April 2020. The closure decision was influenced by rising operational expenses, failure to secure capacity contracts through PJM Interconnection auctions, and unsuccessful efforts to find a purchaser. The entire facility was demolished on December 19, 2021.

Incidents

In February 1982, activists from Greenpeace ascended a smokestack to protest against acid rain, leading to charges of trespassing and short-term imprisonment. In July 2004, an unexpected discharge of molten slag triggered a tank explosion that resulted in the deaths of two employees.

See also

• List of power stations in Ohio