Building Transmission in the Desert: TEP's New Line

Feb. 16, 2016
Tucson Electric Power shares awesome aerial images and process photos of its new Pinal Central to Tortolita 500-kV line.

Tucson Electric Power (TEP) is building a new 500-kV transmission line in Pinal County to ensure continued service reliability for customers in southern Arizona.

The line will extend approximately 41 miles from the Pinal Central Substation east of Casa Grande to TEP's Tortolita Substation, located southeast of the Red Rock area. Field crews are installing high-capacity wires, new metal poles and additional substation equipment for the new line, which will expand access to renewable energy projects and help meet future energy demands in the Tucson metropolitan area and surrounding region.

The line's route, most of which passes though state-owned land, was identified after TEP conducted community meetings and studied its potential impact on natural, cultural and visual resources in a public process that began in 2008. TEP designed the project to minimize disturbance of native vegetation, wildlife and cultural resources. The Arizona Corporation Commission approved the route in 2012.

More than half of the line's approximately 180 steel poles — each 150 ft to 190 ft tall — have been installed, and construction crews will begin stringing wires next month. Work on the project is being performed by TEP with assistance from Atkinson Construction. The $76 million project is expected to be completed in December.

TEP also is nearly finished with upgrades to three 138-kV transmission lines that link substations in the Tucson metropolitan area. Improvement projects like these help to prevent power outages and allow TEP to restore service more quickly when outages occur. The upgraded 138-kV lines will be in service before the summer, when energy demand reaches its peak and powerful thunderstorms can damage equipment.

TEP maintains a robust electrical system that includes approximately 2,400 miles of transmission lines, 2,600 miles of overhead distribution lines and more than 4,300 cable-miles of underground distribution lines. TEP performs system improvements and maintenance projects throughout the year to continue providing safe, reliable service to approximately 414,000 customers in southern Arizona. For more information, visit

TEP and its parent company, UNS Energy Corp., are subsidiaries of Fortis, which owns utilities that serve more than 3 million customers across Canada and in the United States and the Caribbean. To learn more, visit

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