Rolling Hills Generating LLC is nearing permits from the Ohio Environmental Protection Agency that will allow the conversion of its gas-fired, simple-cycle power plant to a combined-cycle facility with a higher capacity level.
On Oct. 3, the Ohio Environmental Protection Agency issued two draft air Permits-to-Install and the Ohio EPA’s Division of Surface Water issued a proposed National Pollutant Discharge Elimination System (NPDES) permit modification to Rolling Hills Generating of Wilkesville, Ohio, according to GenerationHub.
All comments on the drafts must be received at Ohio EPA by 5 p.m. on Dec. 11. A public information session and hearing will be held at 6 p.m. on Dec. 4 at the Wilkesville Community Center.
The proposed NPDES permit change would authorize the discharge of cooling water blowdown and other power plant discharges via a new 16-mile-long outfall pipe from the existing plant site through Vinton, Gallia and Meigs counties to the Ohio River near Middleport, Ohio. An application for a permit to install for the wastewater treatment systems and the outfall pipe would be submitted to Ohio EPA for review and approval after a final action on the NPDES permit.
The draft air permits would allow the modification of four turbines to combined cycle blocks with heat recovery steam generators and duct burners, and installation of two new cooling towers.
Rolling Hills Generating (RHG) owns the Rolling Hills Generating Station (RHGS), which is comprised of five existing gas-fired simple-cycle units located on State Route 160 in Vinton County. RHG proposes to convert four of the five simple cycle peaking units, nominally rated at 209 MW each, to a combined cycle configuration consisting of two 2x1 combined cycle blocks. The existing fifth unit will remain in simple cycle operation.
Inherent to the proposed conversion involving the four units is the addition of four heat recovery steam generators (HRSGs), each of which will be equipped with 550 MMBtu duct burners and a steam turbine generator.
New emission units to be added to the facility as part of this project include cooling towers, a fire pump engine, a diesel fuel tank, and circuit breakers.
This facility was first permitted over a decade ago, consisting of five 209-MW gas-fired simple cycle turbines. The original units have been installed and begun operation in the last two years.
The U.S. Army Corps of Engineers was taking comment this past summer on a Clean Water Act application for this same project. In May 2013, the Ohio Power Siting Board authorized Rolling Hills Generating to increase the capacity of this natural gas-fired facility from 860 MW to 1,414 MW. The proposed conversion was estimated at that point to cost $865 million. This company is affiliated with Tenaska Capital Management LLC.