Guernsey Power Station

Guernsey power station is a 1.8GW gas-fired combined-cycle power plant planned to be built in Guernsey County, Ohio, US.

The $1.4bn project is being developed by Apex Power Group, a privately-held power facility developer based in Indiana, US, in partnership with Caithness Energy, an independent power producer based in New York.

Construction works on the project are expected to be started in the second half of 2019, while commissioning is expected in 2022.

The power station is expected to generate enough electricity for approximately 1.5 million US homes. It is expected to create up to 500 construction jobs and up to 25 permanent jobs during operations.

Location and site details

The Guernsey power station will be built on a 118-acre site in the Valley Township of Guernsey County, near the Utica and Marcellus shale gas development area of Ohio.

Guernsey power station make-up

The Guernsey power station will comprise three single-shaft combined-cycle generating units housed in three separate turbine buildings. Each unit will have a generating capacity of more than 600MW.

Each power train of the facility will consist of a GE 7HA.02 gas turbine paired with an outdoor heat recovery steam generator (HRSG), and a triple pressure reheat steam turbine.

The combustion turbine will be equipped with evaporative inlet cooling as well as low-NOx (DLN) combustors, selective catalytic reduction (SCR) system, and oxidation catalyst for emissions control.

The HRSGs will be equipped with supplemental duct firing capabilities for additional steam generation. The closed-loop cooling system including a dry air-cooled condenser (DAAC) will minimize water usage by as much as 95% compared to conventional water-cooled thermal plants.

The Byesville village will provide fresh water and take back wastewater from the plant for treatment, under a 20-year contract agreement which is renewable.

Power transmission

The electricity generated by the Guernsey power station will be evacuated to the Pennsylvania-New Jersey-Maryland (PJM) Interconnection grid, through interconnection with the existing American Electric Power (AEP) 765kV Kammer-Vassell transmission circuit, which runs through the project site.

Power from the generating units of the facility will be transmitted through 230kV lines that will merge in a switchyard located in the southwestern portion of the project site. The collector bus in the switchyard will house three connected auto transformers as well as a spare transformer to step-up the electricity to 765kV.

The power from there will be further evacuated through an approximately 640m-long 765kV transmission line connecting another switchyard, which will be built on a 15-acre site adjacent to the existing AEP 765kV transmission line.

Natural gas fuel supply

The Guernsey power station will receive natural gas supply from the Utica and Marcellus shale gas formations in eastern Ohio and western Pennsylvania, through the near-by Rockies Express (REX)-East pipeline.

REX-East is a 1,028km-long and 42in-diameter high-pressure natural gas pipeline that originates from the Clarington natural gas hub in Monroe County of Ohio and runs through Ohio, Indiana, and Illinois to Missouri.

Contractors involved

Gemma Power Systems, a wholly owned subsidiary of Argan, was awarded the engineering, procurement, and construction (EPC) contract for the Guernsey power station in January 2019.

POWER Engineers, a global consulting engineering firm based in the US, is the design engineer for the power station.

General Electric (GE) will supply power generating equipment including the 7HA.02 advanced combustion turbines, for all thee power trains of the combined-cycle facility.