Warren County Power Station

Client: Dominion Virginia Power
Completion Date: December 2014
Location: Front Royal, Virginia


Warren County Energy Partners, a joint venture of Burns & McDonnell and Zachry, provided lump-sum turnkey engineer-procure-construct (EPC) delivery of a power facility for Dominion Virginia Power. The 1,300-MW gas-fired Warren County Power Station is on a site about 60 miles from Washington, D.C.

The plant passed all of its performance guarantees, was constructed on schedule and within the owner’s budget. The plant began producing commercial power in December 2014.

We are proud of Warren County Power Station for many reasons. It is already one of the cleanest and most reliable in the nation and was built to be both environmentally and economically efficient. — David A. Christian, CEO, Dominion Energy Infrastructure Group and Dominion Virginia Power

The plant consists of three nominal 255-MW combustion turbine generators (CTGs); three three-pressure, supplementary fired, heat recovery steam generators (HRSGs); a bottom exhaust condensing steam turbine generator (STG); a 60-cell air-cooled condenser (ACC); and associated balance-of-plant materials and equipment.

The net electrical output of the natural gas-fueled facility is a nominal 1322 MW at 92°F and 51 percent relative humidity. For combined-cycle operating mode, the plant is designed and permitted, subject to Virginia Department of Environmental Quality (VDEQ) Prevention of Significant Deterioration (PSD) permit approval. The project is designed for cycling load operation. Each CTG is designed to operate at full load in a pseudo simple-cycle mode where steam from the corresponding HRSG bypasses the steam turbine and is dumped to the condenser.

The project use a thermal energy storage (TES) system designed to produce chilled water for inlet air cooling for the gas turbines. The system produces chilled water in off-peak periods, when electricity rates and demand are lower. The chilled water is stored in a 10 million-gallon TES tank. During peak electrical demand, the chilled water is pumped from the tank to the inlet air coils of the gas turbines to reduce the inlet air temperature to 50°F, increasing the capacity of the plant. The chillers are also capable of providing chilled water directly to the gas turbines. 

Unodorized natural gas is delivered to the site by a new pipeline and is regulated, metered and conditioned on-site. The STG is indoors with a bridge crane for maintenance. The exhaust of the steam turbine is directed to an ACC. The HRSGs are outdoors; the boiler feed pumps are indoors in feedwater pump enclosures. The heat rejection system uses a 60-cell ACC adjacent to the steam turbine building.

Makeup water for the plant is provided at the site boundary by the Town of Front Royal. Makeup water will be used for the CTG TES system, feeds the demineralized water treatment equipment, service water, fire protection water and potable water. A demineralization system produces the demineralized water stored in the demineralized water storage tank. Wastewater and sanitary drains from the facility (process water, closed cycle cooling water, boiler blowdown and domestic wastes) are discharged to the Town of Front Royal wastewater treatment system. Stormwater will discharge through on-site lined stormwater management ponds (SWMPs) equipped with oil/water separators, shut-off valves and hydrocarbon detectors. The hydrocarbon detectors are monitored and alarmed in the distributed control system (DCS). 

One gas-fired auxiliary boiler produces steam for preheating piping and equipment as required for plant startup and for supplying initial steam to the turbine gland seal steam system. The auxiliary boiler is designed for indoor installation.

Plant synchronization to the 500-kV substation is accomplished through low-side generator breakers for the CTG units and high-voltage generator breakers for the STG. A plantwide DCS) monitors and controls the balance-of-plant materials and equipment. 

Nitrogen oxide (NOx) emissions are controlled by dry low-NOx (DLN) combustors. A selective catalytic reduction (SCR) system is included with each HRSG to further reduce the NOx level. Carbon monoxide (CO) and volatile organic compound (VOC) emissions are reduced by an oxidation catalyst in each HRSG.


  • Engineering
  • Procurement 
  • Construction
  • Startup and commissioning


Warren County Power Station was awarded Overall Project of the Year and Best Natural Gas-Fired Project by Power Engineering magazine in December 2015. The awards honor projects that are innovative, beneficial to their communities and technologically groundbreaking.
  • Greenfield site
  • Natural-gas fueled
  • 3 Mitsubishi M501 GAC gas turbines with dry low NOx combustors 
  • 3 Alstom triple-pressure supplementary-fired (500 MBtu/hour each) HRSGs
  • 1 Mitsubishi tandem compound 4-flow reheat CST
  • SPX 60-Cell air-cooled condenser
  • 10 million-gallon TES tank
  • 3 chillers and associated chilled water coils