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Coolidge Expansion Project

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

About the project

Coolidge Expansion Project Update

On February 17, SRP filed a notice of appeal with respect to the January 20 Superior Court decision to affirm the ACC’s previous denial of the Coolidge Expansion Project’s Certificate of Environmental Compatibility (CEC).

SRP is seeking to appeal directly to the Arizona Supreme Court. SRP believes the Superior Court decision was incorrect regarding its interpretation and application of the factors that must be considered under the Arizona line siting statute, and that the Superior Court should have granted SRP’s appeal.

SRP maintains the flexible-fast ramping Coolidge Expansion Project is the best option to meet our customers’ energy needs without compromising reliability. It also remains the best option to enable SRP’s efforts to reliably add to its robust portfolio of renewable resources, such as 2,025 megawatts of solar energy which will be online by 2025, and over 800 megawatts of battery storage projects online by 2024, which is enough to power more than 180,000 average size homes for up to four hours.

Salt River Project Agricultural Improvement and Power District (SRP), a community-based, not-for-profit utility based in Tempe, Arizona, is applying for a Certificate of Environmental Compatibility (CEC) for the expansion of the Coolidge Generating Station.

The Coolidge Generating Station is a natural gas power plant near Coolidge, Arizona, that was built between 2009 and 2011. SRP purchased the plant in 2019 to help support growing demand for power in the region.

The proposed Coolidge Expansion Project (CEP) will allow SRP to meet the significant near-term increase in energy needs in its service territory, which is among 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.

A virtual open house is available and can be viewed on-demand, 24 hours a day.

As part of the CEC process, SRP is seeking public input for the Coolidge expansion, which would include construction of up to 820 megawatts (MW) of new power generation produced by 16 gas turbines.

Project need

The proposed Coolidge Expansion Project (CEP) is needed to meet the significant near-term increase in energy needs in SRP's service territory, which is among 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 deep 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 has committed to add 2,025 MW of solar energy to its renewable portfolio by 2025. 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.
  • 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.

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

May 13, 2022
SRP to Request the ACC Rehear Its Decision to Deny the Coolidge Expansion Project

On Monday, May 16, SRP will file a request for rehearing by the Arizona Corporation Commission (ACC) to reconsider its decision to deny SRP a Certificate of Environmental Compatibility (CEC) to expand its peak-demand natural gas facility in Coolidge. Unless reconsidered and reversed, the ACC's vote will impair the reliability of the SRP system, creating serious risk of insufficient resources necessary to meet customer demand in 2024. It will also undermine SRP's ability to integrate additional renewable resources, as the utility will lack critical quick-start, flexible generation in times of peak demand.

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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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