Northwest Marana Reliability Project
Tucson Electric Power is developing new transmission facilities that will reinforce critical systems that provide safe, reliable service and support growing energy needs in Marana and the surrounding area.
The Northwest Marana Reliability Project will interconnect the planned Owl Head Ranch Switchyard and Grier Substation and interconnect the Grier Substation to a previously approved transmission line along West Marana Road.
In June 2025, the Arizona Power Plant and Transmission Line Siting Committee voted to grant TEP’s application for a Certificate of Environmental Compatibility (CEC). The Arizona Corporation Commission reviewed and approved the CEC in August 2025.
Construction of the new 9-mile line, a new half-mile line, the Grier Substation, and Owl Head Ranch Switchyard are expected to be complete in 2028.
For project related inquiries, please send an email to nwmarana@tep.com or call 1-833-655-0399 to leave a voice mail.
More Information
- Final Approved Route:
PDF Map | Interactive Map - Order Approving Certificate of Environmental Compatibility – August 2025
- Online Comment Form