Coolidge Generating Station

WSP USA, in joint venture, provided design and construction services for this 575 MW simple cycle power plant featuring a rapid start-up capability and reduced environmental footprint.



  • Arizona, USA


  • TransCanada Corporation

Project Status

  • Completed in 2011

Peaking Power Plant with Rapid Start-Up Capability

The Coolidge Generation Station is a 575-megawatt simple-cycle peaking power plant in Arizona that is one of the largest peaking plants in the U.S. We designed and constructed the plant, in joint venture, under an engineer-procure-construct (EPC) contract.

The plant uses 12 aero-derivative combustion turbine generators (aircraft engine technology) with evaporative cooling power augmentation. It was designed for daily start/stop peaking operations, and its 10-minute rapid startup capability allows it to deliver power swiftly to the grid when there is an increase in demand for electricity.

The plant can operate at ambient temperatures as high as 122 degrees Fahrenheit to deal with the local climate. It is also able to operate during extreme winter conditions by employing anti-icing systems.


Key Numbers

Generating capacity
575 MW
Homes served

Reduced Environmental Impact

Several features were incorporated into the design to help reduce the plant’s environmental footprint. The combustion turbine generators use pipeline-quality natural gas as the fuel source, rather than coal or oil. Selective catalytic reduction technology helps to reduce greenhouse gas emissions. In addition, water for the plant is supplied from on-site wells, and wastewater goes to on-site evaporation ponds rather than to the local sewer system.

We provided all engineering services, including civil, structural, mechanical, electrical and control systems engineering, for the plant’s development. We also provided engineering support during construction, and developed start-up and operating procedures for the plant. The Coolidge power station was successfully completed ahead of schedule and under budget.