Grid Improvements for More Reliable Service

TEP’s proposed transmission line and substation projects are designed to enhance our local energy grid while preparing for our community’s future energy needs. Public outreach is an important part of TEP’s planning process. Click below to learn more about current projects.

Tucson Electric Power: Transmission Lines

Transmission Lines

Transmission lines link substations and other facilities to move electrical energy at high voltages over long distances.
Tucson Electric Power: Substations


Substations change the voltage of electric facilities for distribution and delivery of electric service to area customers.
Tucson Electric Power: Working in Your Neighborhood

Working in Your Neighborhood

Our crews are working to improve resiliency and reliability. Stay informed about some of our larger projects that may be occurring in your area.

How does your company determine where it needs to build new transmission lines?

TEP analyzes forecasted customer energy needs, energy efficiency programs, distributed generation and other factors to prepare its 10-Year Transmission Plan, which describes how TEP expects to maintain and improve transmission and other facilities over the next decade to meet the forecasted conditions and third-party interconnection requests.

To prepare the plan, TEP conducts an annual review of its existing Bulk Electric System as defined by the standards of the North American Electric Reliability Corporation (NERC). The review helps ensure TEP can plan for the system's maintenance and improvement in accordance with NERC standards. The plan describes:

  • Prospective transmission line projects above 115 kilovolts that TEP intends to initiate over the next decade to maintain reliability and meet customers future energy needs.
  • Upgrades necessary to maintain reliable service.
  • System locations where new transmission facilities may be required.

The plan is filed annually with the Arizona Corporation Commission, which must review and approve individual transmission line projects before construction can begin.

What else is TEP doing to prepare for customers' future energy needs?

TEP is planning a dramatic expansion of clean energy resources that will allow us to provide 70 percent of our power from renewable resources while reducing carbon dioxide emissions 80 percent by 2035.

This ambitious, realistic vision for a sustainable energy future is detailed in TEP's 2020 Integrated Resource Plan (IRP). The IRP provides regulators, customers and other interested stakeholders with information about current resources, detailed assumptions and analyses about future energy requirements, and strategies for meeting our customers’ long-term energy needs.