Irvington-East Loop Transmission Line

The Arizona Corporation Commission voted on April 22, 2020 to approve the Certificate Environmental Compatibility.

• Irvington-East Loop 138 Kilovolt – ACC Order Approving CEC 

The Arizona Power Plant and Transmission Line Siting Committee voted to approve TEP's application for a Certificate of Environmental Compatibility at a public hearing held Feb. 24-26, 2020.

• Certificate of Environmental Compatibility (issued 3-3-20)
• Line Siting Hearing transcript — Day 1
• Line Siting Hearing transcript — Day 2
• Line Siting Hearing transcript — Day 3
• Application for a Certificate of Environmental Compatibility

TEP conducted a siting analysis to identify multiple potential line route segments that could combine in various ways to form a final route. Throughout 2019, TEP held public meetings and conducted other outreach efforts.

Based on residents’ comments and additional data provided by other local utilities, TEP expanded the preliminary study area to allow consideration of additional route options. The company used input from the public to identify  submitted with its application for a Certificate of Environmental Compatibility (CEC) from the Arizona Corporation Commission.

TEP encouraged residents, property owners and other stakeholders to participate in the process by attending public open house meetings, filling out an online comment form, sending letters or calling the project hotline at (520) 382-4662 to offer comments and ask questions.

In determining where to locate new energy infrastructure, TEP considers the projected energy needs of nearby residential and commercial customers, anticipated economic development, proximity to existing equipment, project costs, geography, the environment, public input and other factors. Transmission lines link substations that change the voltage of electric current for distribution and delivery of electric service to area customers.

TEP is evaluating potential transmission line routes within a defined study area that could interconnect existing and planned substations that include:

• Irvington Substation (terminus point): TEP is upgrading and relocating this substation to expand capacity and accommodate new generating resources at the company’s Irvington Campus, located near South Alvernon and East Irvington roads.
• Port Substation (planned point of interconnection): TEP plans to build this substation on a 10-acre site near South Kolb and East Valencia roads at the Port of Tucson, an intermodal inland shipping and storage facility supporting the transportation of goods throughout the Southwest. The planned substation is designed to accommodate increased energy demands and economic growth in the area. An in-service date has not been determined.
• Patriot Substation (planned point of interconnection): TEP is building this substation on a 16-acre site near South Kolb and East Escalante roads at Davis-Monthan. The new substation will help Davis-Monthan meet Department of Defense-mandated energy resiliency directives, replace aging infrastructure that has reached the end of its useful life and strengthen electric reliability for customers in the area. The substation is scheduled to be in service in 2023.
• East Loop Substation (terminus point): Located near East Speedway Boulevard and South Kolb Road, this existing substation feeds multiple circuits that deliver electric service to homes and businesses throughout the area.

The Irvington-East Loop line would cross private property and government-owned land in the City of Tucson and portions of unincorporated Pima County. TEP would build the line with self-weathering steel monopoles that stand between 75-110 feet tall. Taller structures may be required at major road or line crossings.

The Arizona Corporation Commission (ACC) must approve a Certificate of Environmental Compatibility (CEC) before construction can begin on the transmission line.

TEP submitted its application for a CEC in January 2020 to the Arizona Power Plant and Transmission Line Siting Committee (LSC). The committee reviewed the application in a public process that included opportunities for neighbors and other stakeholders to provide comments. The LSC granted the CEC in February 2020. The Arizona Corporation Commission reviewed and approved the CEC in April 2020.

Construction of the Irvington-East Loop transmission line started in 2021 and is expected to be in service before the end of 2023.

The City of Tucson approved a development plan and issued a special exception land use permit for the Patriot Substation in summer 2021. The substation is expected to be in service before the end of 2023.

The City of Tucson also must approve a development plan for the Port Substation prior to construction. TEP has not determined when it will file this plan. Current zoning will accommodate substation construction.