As headlines across the country highlight grid reliability concerns driven by extreme weather, rapid growth, and infrastructure needs, Tucson’s story stands apart. This community faced one of its hottest and driest summers on record, but our local energy grid proved resilient, delivering reliable service even as demand surged to unprecedented levels.

On August 6, TEP recorded a new hourly demand peak of 2,502 megawatts (MW), surpassing forecasts and reflecting our community’s growing energy needs. Despite the additional demand driven by the day’s 111-degree heat, our grid held strong thanks to years of strategic investments in system upgrades and maintenance.

Built for Today’s Demands

Since 2021, TEP has committed approximately $1.7 billion to modernize and reinforce the systems that power homes, businesses, and essential services across our 1,155-square-mile service area. Of that, $758 million was invested in substations, power lines, and other critical infrastructure.

Maintaining reliability across our vast network requires ongoing upgrades to more than 5,100 miles of overhead lines, 4,300 miles of underground lines, 120 substations, and over 107,000 poles and transmission structures. Recent highlights include:

• Upgrading distribution lines: In 2024 alone, we invested $25 million in conductor upgrades and voltage conversion projects to boost capacity and improve service delivery.
• Enhancing substations: Key investments in 2024 included $16 million for our new Cottonwood Substation, $4.9 million for improvements at Irvington Substation, and $3.6 million for a major transformer addition at our Pantano Substation.
• Replacing aging infrastructure: TEP continues to replace older wooden poles with steel alternatives, investing over $4 million annually in this effort over the past five years.

These upgrades contribute to TEP’s reputation as one of the nation’s most reliable electric service providers. More details on current projects can be found at tep.com/projects.

Planning for the Future

TEP is preparing for a significant increase in energy demand over the next decade, driven by factors such as data center development, industrial growth, and broader electrification trends. While the company’s 2023 Integrated Resource Plan (IRP) projected annual growth of about 1 percent, recent discussions suggest demand could increase by 50 percent or more over the coming decade.

To meet this challenge, TEP is pursuing an “all of the above” energy mix to ensure a balanced approach to providing reliable power at an affordable price. While solar and storage will play an increasingly prominent role in our energy mix, it must be part of a balanced portfolio that provides both affordability and reliability for our community.

Key initiatives already underway include:

• Roadrunner Reserve: This summer, we energized a new four-hour, 200 MW battery energy storage system in southeast Tucson that’s capable of powering 42,000 homes for four hours. The system, built at a cost of approximately $350 million, helped us maintain reliability during peak usage periods this past summer with affordable solar energy produced earlier in the day. A second 200 MW phase of the system is under construction and should be complete by next summer.
• Springerville Generating Station conversion: Two coal-fired units at this Eastern Arizona plant will be converted to operate on natural gas by 2030, reducing emissions while maintaining reliable service and preserving jobs.
• New clean energy projects: Developers are working to complete several new renewable energy systems that will come online by 2027 to serve TEP customers. These include Babacomari Solar (160 MW), Wilmot Energy Center expansion (100 MW solar + 100 MW storage), and Winchester Solar (80 MW solar + 80 MW storage).

These new resources and continuing investments in our local energy grid will help us maintain our top-tier reliability as we bring new customers online, including potential data center projects. Before connecting new businesses with significant energy demands, we conduct system studies to ensure they can be served without compromising the top-tier reliability we provide our other customers.

As energy needs evolve, TEP remains committed to building a grid that is safe, resilient, and ready for the future.

By Ana Bustamante, Vice President of Energy Delivery for Tucson Electric Power