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Coolidge Expansion Project

See how new generation infrastructure will help meet growing power demand.

About the project

Construction Activity
We expect construction activities to commence in the spring of 2024 with the completion and commercial operation of the first six natural gas turbines by June 2026 and completion of the second six no later than June 2027. This schedule includes work on the new 500 kV switchyard, modifications to the existing 230 kV switchyard and transmission lines. All construction will be taking place on SRP-owned land.

As part of the approved Coolidge Expansion Project plan, 575 megawatts (MW) of new power generation produced by 12 gas turbines will be constructed. That’s enough energy to power more than 139,000 average-size homes at once while also supporting the integration of wind, solar and batteries on our system. 

Like all of SRP’s generation facilities, it will comply with all local, state and federal air quality regulations which are protective of human health and the environment.

Project need

The proposed Coolidge Expansion Project (CEP) is needed to cost-effectively and reliably meet the significant near-term increase in energy needs in SRP's service territory, which is located in one of the fastest-growing regions in the nation. In addition, the CEP will enable the addition of more renewable resources while maintaining a reliable power grid. The CEP will ensure that SRP can meet these objectives while staying on the path to achieve our aggressive decarbonization goals over the long term.

Benefits of CEP

  • Meeting Near-term Demand: One of SRP's primary responsibilities to the communities we serve is to provide reliable electric service. The CEP will allow SRP to fulfill this obligation in the face of strong economic growth in SRP's service territory.
  • Reliable Integration of Renewables: SRP is developing over 1,500 MW of additional large-scale solar. Once online, these assets will push our total solar energy to more than 2025 MW—enough to power 450,000 average size homes. However, along with increased solar generation comes more variability in power output, especially during cloudy conditions. The CEP includes quick-starting (10 minutes) and fast-ramping power generation resources that can smooth out these fluctuations and ensure SRP delivers consistent, reliable power. Resources like Coolidge Generating Station are critical as we continue to bring online thousands of megawatts of new solar and wind as well as 1,110 MW of batteries, one of the largest energy storage commitments in the West, in the years ahead. With this project and other strategic resource additions, more than 75% of energy delivered to SRP customers will come from carbon-free resources by 2035. Our diversified energy portfolio taps into the most efficient, available and cost-effective mix of generation resources. Learn more about our ongoing sustainability efforts as well as our plan for the future.
  • Importance of Location: The CEP location allows SRP to leverage the existing Coolidge Generating Station site and infrastructure while also ensuring a better balance of power generation located in the East Valley with power generation located in the West Valley. This will help to optimize the overall power transfer capability, reliability and flexibility of SRP's transmission system.
  • Lowest-Cost Option: SRP has recently conducted multiple RFP processes, which have confirmed that the CEP provides our customers with the lowest-cost option to address the growing energy needs of our service territory while ensuring we continue to meet our Board-approved sustainability goals. The CEP is critical to our published goal of achieving 65% carbon intensity reduction by 2035 and 90% by 2050, because it will enable the addition of more renewable resources while maintaining the reliability of SRP's power system. 

Proposed expansion site

Existing Coolidge Generating Station

Contact us

If you have questions about the project, please contact us or call (602) 236-2872.

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News Archive

June 21, 2023
SRP Coolidge Expansion Project Approved by the ACC

The Arizona Corporation Commission (ACC) today approved an amended Certificate of Environmental Compatibility (CEC) for the Coolidge Expansion Project, a flexible, fast-ramping natural gas plant that will help SRP cost-effectively and reliably meet the region’s growing energy needs as the utility works to add more solar, wind and storage resources.

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August 24, 2021
SRP Announces Plans to Expand its Coolidge Generating Station to Deliver Reliable Power and Support Renewable Resource Growth

As a not-for-profit, community-based utility that serves more than one million energy customers in America's fastest growing region, SRP announced it is seeking Board approval to expand its Coolidge Generating Station, a quick-start natural gas power plant located in the Southeast Valley. The expansion will help SRP integrate more renewable energy resources into the power grid and allow SRP to provide reliable power to its rapidly growing customer base during times of peak electricity demand, including some of the hottest days in Arizona's summer season.

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