
Coolidge Expansion Project
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About the project
Construction Activity
Construction activities began in the spring of 2024. We expect the completion and commercial operation of the first six natural gas turbines by Summer 2026 and completion of the second six no later than Summer 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: To meet SRP’s Board approved sustainability goals to reduce carbon intensity 82% by 2035 and net zero by 2050 we are adding thousands of megawatts of solar resources to our system. 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 batteries 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 82% carbon intensity reduction by 2035 and net zero 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.
News Archive
SRP Coolidge Expansion Project Approved by the ACC
SRP Announces Plans to Expand its Coolidge Generating Station to Deliver Reliable Power and Support Renewable Resource Growth
- Read the Coolidge Generating Station article (Opens in a new tab) featured on azcapitoltimes.com.
- Listen to the Coolidge Generating Station story on KJZZ (Opens in a new tab) featured on 91.5 KJZZ.






