Reliability Upgrades

Two APS workers discussing project at a construction site

Construction Projects

We continuously work to improve our systems and service throughout Arizona to support reliability for our customers. We are committed to keeping customers, communities and stakeholders informed about upcoming projects around the state. Learn more about our future-focused projects that support reliable service for customers.

Central Phoenix Line Upgrade

We upgraded a critical underground transmission line in central Phoenix – the “backbone” of the metro Phoenix 230kV transmission system. This upgrade supports reliability for customers as it replaced a line that was reaching the end of its design life. This project also expanded the capacity of the line to support customers’ growing energy needs and began serving customers in summer 2024. Additional segments of this line will be upgraded in the coming years (2026-2027).

Walker Road Upgrade

We plan to relocate 4.4 miles of 12 kilovolt (kV) line in the south Prescott Forest, west of Walker Road, to the APS right-of-way along Walker Road between Big Bug Mesa Road and Liese Drive. These lines have been providing power to the communities of Walker, Potato Patch and Lynx Lake for nearly 100 years and are nearing the end of their operational life. The new overhead power lines will be placed on 45' to 55' steel and wood poles, similar to poles that already exist along Walker Road. View the project website.

Natural Gas and the Transition to Clean Energy

Natural gas is an essential resource during the clean energy transition – and an important partner to the large quantity of renewables and energy storage we’re adding to our system. In late June 2023, we issued a competitive request for proposals (RFP) seeking additional megawatts (MW) of incremental natural gas capacity at our Redhawk and Sundance locations (see below). We expect to add five times as much renewable energy technology in the same time period.

Natural gas supports the reliable service our customers count on, providing much-needed energy during late-afternoon and evening hours when customers use it most. Through our competitive procurement process, we’re evaluating these projects and additional resources to support Arizona’s growing energy demand and protect reliability and affordability for customers.

  • Redhawk Project - If selected in the RFP, the potential project at the existing Redhawk Power Plant, located in Arlington, would add approximately 397 MW of critical energy capacity, enough to serve 63,520 Arizona homes. Construction would be targeted for completion by 2028. View the Redhawk project website.
  • Sundance Project - The Sundance Power Plant, located 55 miles southeast of Phoenix near Coolidge, is a key component of our energy infrastructure. If selected in the RFP, the plan would be to build two additional natural gas units at Sundance – adding 90 megawatts (MW), enough energy to serve an additional 14,400 Arizona homes. We would expect construction to begin in early 2025, with the two units in service for summer 2026. View the Sundance project website.
  • West Phoenix Upgrade - We’re making a minor upgrade to one of the existing units at the West Phoenix Power Plant, which will improve the efficiency of the unit and help us maintain reliable service, especially during the peak summer months. We plan to start work in spring 2024 with the unit back in service ahead of summer 2024.

Downtown Phoenix Substation Projects

Several interconnected substation projects and related powerline upgrades in Phoenix support reliable service in the bustling downtown.

  • Evans Churchill Substation - Located at 7th Street and Roosevelt Street, the distinctive “Roosevelt Row” substation upgrade was completed in 2022. We continue to work on powerline upgrades that serve critical customer projects in the downtown. Those powerline upgrades are expected to be completed in 2024.
  • Garfield Substation - Garfield Substation is located near 2nd Street, south of Roosevelt to Garfield. The demolition and rebuild of Garfield Substation will follow the energization of the new Evans Churchill network. The new substation design includes a multi-use component on Roosevelt Street, which will include offices for Roosevelt Row and art gallery space. The design also includes active pedestrian space, public art and shade. The engineering, permitting and neighborhood outreach will take place throughout 2023 and 2024. We expect this project to be complete in early 2026.
  • Grant Street Substation - This project will expand the footprint for the three Lincoln Street substations at 4th Avenue and Lincoln Street. Construction is scheduled to start in 2024. View project website

Two APS employees looking at blueprints.

Line Siting Projects

As Arizona grows, we must plan and build new power lines to safely and reliably meet our customers’ energy needs.
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