Ocotillo Modernization

APS is planning to modernize the Ocotillo Power Plant in Tempe. The proposed project will create a cleaner-running, more efficient plant using advanced technology. APS intends to install five combustion turbines powered by natural gas. Two existing 1960s-era units will be removed.
The project is critical to the Phoenix metro area and provides several benefits. It supports service reliability, improves the plant’s appearance, is better for the environment, creates construction jobs and adds additional tax revenue to the local economy.
We welcome feedback from the public about the project. Please complete the form below to share your comments or be added to the mailing list. 

Ocotillo Modernization Snapshot


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Public comment session set for April 7

The Maricopa County Air Quality Department will hold a public comment session for the Ocotillo Modernization Project air permit on April 7.

April 01, 2015
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Ocotillo Earns Recognition from ADEQ

The Arizona Department of Environmental Quality selects Ocotillo Power Plant as a charter member of its state Voluntary Environmental Stewardship Program.

March 19, 2015
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APS Receives Tempe Business Excellence Award

The Tempe Chamber of Commerce recently honored APS with its Beacon Business Excellence Award in the Large Business category.

March 10, 2015
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Corporation Commission Authorizes Ocotillo CEC

The Arizona Corporation Commission unanimously approved a Certificate of Environmental Compatibility (CEC) for the Ocotillo Modernization Project.

November 05, 2014
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Ocotillo Modernization on ACC Agenda

The Arizona Corporation Commission is scheduled to consider a Certificate of Environmental Compatibility for the Ocotillo Modernization Project.

November 03, 2014
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What is the project timeline?
Demolition of the five large oil storage tanks, which are no longer in use, is planned for winter 2016. Construction on the new units would begin in 2017 and be completed by summer 2019. Removal of the old units would begin in 2019.
Why upgrade the Ocotillo plant?
The Ocotillo plant is critical to maintain service reliability in the Phoenix metro area because of its location. We can also improve an existing plant without changing its overall footprint. The planned new units are also more responsive – they can start up and begin delivering electricity in less than six minutes and reach full power in 10 minutes. The old units can take six hours or more just to start.
What will be the environmental benefits?
Replacing the obsolete steam generators with much newer, proven, cleaner technology will greatly improve the plant’s efficiency. The new units will decrease the plant's water-use and emission rates. They will also improve the plant's overall noise conditions.
How tall will the new structures be?
The plant currently has four 178-foot stacks, while the upgraded plant is planned to have five stacks about half as tall. This would significantly reduce the plant’s visibility from several locations. 

What economic benefits will the project provide?
It will create local jobs – we expect the project to require an average of more than 100 jobs during construction. Total property taxes for the upgraded plant are expected to increase to about $8 million by the fifth year of operation. APS currently pays about $600,000 in total property taxes for Ocotillo.

How can I get involved in the project? 
APS is committed to a transparent public process. The public can submit comments on the project through the form above. In addition, we held a public open house to provide information and take comment, and we have participated in public forums for government agenices that provide oversight of various project components.

View more FAQs about the Ocotillo modernization project.


  • Ocotillo Modernization Project
    Ocotillo Modernization Project