The U.S. Army Corps of Engineers is taking comment until July 8 on a Clean Water Act application from Rolling Hills Generating LLC related to a planned conversion of a simple-cycle power plant into a combined-cycle power plant.
The Rolling Hills Generating Facility is located north of the Village of Wilkesville in Vinton County, Ohio. The upgrade project would involve construction of two water lines in a single right-of-way corridor from that location to the southeast and terminating at the Ohio River in Meigs County, Ohio.
The project proposes a water intake structure on the Right Bank at Ohio River Mile Point 255.1, according to GenerationHub.
“The applicant is proposing to convert the current Rolling Hills Generating Facility from a simple cycle electric generating facility to a combined cycle electric generating facility,” said a Corps notice. “The current generating facility utilizes a simple cycle combustion process via five natural gas fired combustion turbines. The conversion would require expansion and redevelopment of the current generating facility, adding four heat recovery steam generators and two steam generators to four of the combustion turbines. One combustion turbine would remain as a simple cycle unit.”
The converted generating facility would require outfall and intake structures at the Ohio River. Installation of a pump station and access road near the outfall and intake structures would not fill any waters of the U.S. Installation of the intake structure would require dredging and placement of rip-rap and would permanently fill about 0.12 acres below the ordinary high water mark of the Ohio River to an average depth of 2.0 feet. Annual maintenance dredging at the intake structure would be required to an average depth of 5.0 feet.
This conversion project would permanently fill six wetlands totaling 0.67 acres, a 0.014 acre pond, and six ephemeral streams totaling 1,928 linear feet at the Rolling Hills Generating Facility site. These streams and wetlands are currently located just outside the power block fence line and would be permanently filled to accommodate the expanded footprint required for the conversion.
In May 2013, the Ohio Power Siting Board authorized Rolling Hills Generating to increase the capacity of its existing natural gas-fired facility in Wilkesville from 860 MW to 1,414 MW. The proposed conversion was estimated at that point to cost $865 million and would result in a combined-cycle natural gas-fueled generating facility with a capacity of 1,414 MW.
Conversion of the plant would use all five of the existing Siemens 501FD2 natural gas-fired combustion turbine generators. One combustion turbine would remain in simple-cycle configuration with a nominal output of 172 MW. Four of the five combustion turbines would be coupled to Heat Recovery Steam Generators and each would be equipped with 550 million British thermal units per hour (MMBtu/hour) duct burners. Each pair of gas combustion turbines would be combined with HRSGs and a steam turbine generator set to create 2x1 power blocks, each with a nominal output of about 621 MW.
This company is affiliated with Tenaska Capital Management LLC.