The Virginia Department of Environmental Quality filed a Sept. 4 report with the Virginia State Corporation Commission that it has been able to resolve minor environmental issues over an Appalachian Power plan to convert two coal units at the Clinch River power plant to burning natural gas.
Appalachian Power (APCo), a unit of American Electric Power (NYSE: ASE), submitted an application in May to the State Corporation Commission (SCC) for Certificates of Public Convenience and Necessity (CPCN) to convert existing coal-fired units to gas-fired units at the Clinch River plant located in Russell County, Va. APCo is proposing to modify two of the three coal-fired units and retire the third.
The project also will include the installation of a natural gas-fired auxiliary boiler, approximately 4,000 linear feet of underground gas piping from the pressure-reducing station to the boiler building, a verification gas metering station and associated equipment.
The APCo application submitted for review included conflicting, inaccurate or preliminary statements which required additional coordination and clarification, the DEQ noted. While these statements were few, they conveyed pertinent information that affected reviewers’ comments and could have affected the list of potential permits and approvals which DEQ is required to submit to the SCC.
For example, there were concerns regarding wetlands and water withdrawal permits, existing consent orders, building construction, and the extent of APCo’s permitting responsibility. However, all issues were resolved during the review. APCo submitted a revised report and confirmed that in-stream work and wetland impacts are not proposed for the APCo-owned segment of the gas pipeline.
“Reviewers did not identify any adverse impacts that could not be mitigated,” the DEQ said. “Therefore, DEQ has no objection to the proposed project.”
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Among those writing original application testimony for the Virginia commission was John Torpey, employed by American Electric Power Service Corp. (AEPSC) as Director-Integrated Resource Planning. The Clinch River gas conversion is a viable option to provide APCo with adequate capacity beyond 2015, Torpey noted. With capacity from the gas-converted Clinch River units, APCo will not require additional capacity until the converted Clinch River units are retired, which, for planning purposes, is assumed to be 2025.
There are a number of environmental rules that will impact APCo’s ability to operate its generating fleet in the future. To comply with these rules, APCo plans to retire 1,245 MW of coal-fired capacity prior to the 2015/2016 PJM Interconnection plan year, and to convert Clinch River Units 1 and 2 to natural gas. But, APCo can meet its PJM capacity obligation through 2024/2025 by converting two of the three Clinch River units.
The Clinch River plant began operating over fifty years ago, in 1958. Units 1 and 2 were completed in 1958, with a nominal generating capacity of 235 MW for each generating unit. Unit 3 was completed in 1961, also with 235 MW of nominal capacity. In recent years the units have aged and environmental requirements have evolved, so they have been used as “cycling” units (i .e. use is based on hourly system demand level rather than continuous use) and the frequency of usage has declined to some degree.
As a result of the EPA’s Mercury and Air Toxic Standards (MATS), the company is faced with a choice of whether to retrofit Clinch River, convert all or part of the plant to natural gas or retire the units and purchase replacement power from the market. A conversion of Clinch River Units 1 and 2 to natural gas and the retirement of Unit 3, is the best alternative to meet the capacity need taking into account economic and environmental considerations, as well as recognizing fuel diversity. The conversion of Unit 3 is not required to meet anticipated load levels.
After conversion, Clinch River 1 and 2 will be nominally rated at 2,461 mmBTU/hr each and 242 MW net generation. The conversion is anticipated to begin construction in the second quarter of 2015, with Unit 1 completed by the end of the fourth quarter of 2015 and Unit 2 completed by the end of the second quarter of 2016.
Units 1 and 2 are expected to maintain their current generating output capability of about 247 MWg with no change anticipated in the generators’ nameplate rating. The expected net dependable capacities for each unit after the conversion are 242 MWn (winter) and 237 MWn (summer).