Northwest Marana Reliability Project

Tucson Electric Power’s Northwest Marana Reliability Project will reinforce critical systems that provide safe, reliable service and support growing energy needs in Marana and the surrounding area.

TEP has identified potential alternative routes for new 138-kilovolt (kV) transmission facilities to interconnect the planned Owl Head Ranch Switchyard and Grier Substation, and to interconnect the Grier Substation to a previously approved transmission line now under construction along West Marana Road. Click here to view a map or an interactive map of the potential alternative routes.

TEP encourages residents and other interested parties to share feedback about these alternative routes by filling out an online comment, by sending comments to nwmarana@tep.com, or by calling 1- 833-655-0399.

Project Need and Benefits

New, modern energy delivery systems are needed to replace older, lower-voltage equipment that cannot keep pace with the increasing energy use in Marana. Peak power demand in the area has nearly reached the capacity of the older system, which reduces electric reliability and results in longer power outages in some areas.

The project will include building a new approximately half-mile, 138-kilovolt (kV) transmission line segment from the planned Grier Substation to a 138 kV line north of the substation along West Marana Road built in partnership with Arizona Electric Power Cooperative (AEPCO).

Additionally, TEP would construct a new 138 kV transmission line segment connecting the Grier Substation to the planned Owl Head Ranch Switchyard, which would be located on about 20 acres east of Interstate 10 on North Owl Head Ranch Road. This segment will be built as a single-circuit transmission line but designed to accommodate a second circuit to accommodate future growth. The circuit is expected to be approximately 5-10 miles long.

These new facilities would interconnect with an existing 138 kV line that runs parallel to I-10 and links TEP’s North Loop and Tortotlia substations.

The Project would provide many benefits to local residents and businesses, including:

Improved electric reliability through a looped system that will help reduce the frequency and duration of outages.
Greater transmission capacity to meet the growing energy needs of customers in the area.
Greater energy capacity to better accommodate customer-owned energy systems.

Maps

Outreach Materials

Mailings

Newsletter – Nov. 2024
Postcard – Jan. 2025
Postcard – March 2025

Interested Parties Meetings

Agency Briefing – Nov. 2024
Agency Briefing – Jan. 2025
Agency Briefing – March 2025

Open House

Display Boards – Nov. 2024
Display Boards – Jan. 2025
Display Boards – March 2025
Visual Simulations – March 2025 148mb

Virtual Open House

Click Here to View Virtual Open House – Feb. 2025

Required Approvals and Timeline

Under state law, TEP must obtain a Certificate of Environmental Compatibility (CEC) to construct system improvements. TEP plans to file a CEC application in summer 2025 with the Arizona Power Plant and Transmission Line Siting Committee, which reviews CEC applications in a public process that allows neighbors and other stakeholders to provide comments. The Arizona Corporation Commission must review and approve the CEC before TEP can begin construction. The project is planned to be in service by 2028.

TEP has not identified routes for the line segments and is seeking public input to identify route opportunities and constraints. The final route is subject to approval by the Arizona Power Plant and Transmission Line Siting Committee and the Arizona Corporation Commission.

Public participation is an integral part of TEP’s planning process. We encourage area residents and other stakeholders to share their comments using one of the methods listed here.

Public Participation

Northwest Marana Reliability Project

More Information

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