As a leader of the team that operates our local energy grid, I’d like to explain how Tucson Electric Power can maintain our top-tier, 99.9% reliability while serving new customers with large energy needs.
TEP does not connect new customers to our grid unless we’re confident we can serve them reliably. For large energy users, we conduct detailed studies to assess potential impacts on our system, including load forecasting, contingency analysis, and resource adequacy. If new resources are needed, we make plans for their construction and develop contracts to ensure that new customers cover the cost of all systems dedicated to their use.
Through these efforts, we’ve determined that TEP can serve the initial phase of the proposed data center on the southeast side with existing resources and those coming online soon. Future phases would be subject to the same rigorous planning process and a new energy supply agreement that addresses the potential need for new energy resources.
Once new customers are online, our team is responsible for real-time reliability across a complex network of loads and resources. We regulate the balance between supply and demand at all times to maintain the grid’s frequency at 60 Hz (cycles per second) — a standard that underpins the safe operation of motors, generators and inverter-based resources like solar photovoltaic panels and batteries.
When usage fluctuates due to weather, industrial activity, or residential needs, we respond immediately. If generators trip offline or solar energy output varies, we adjust. Our system is designed to handle these dynamics, and we follow strict standards set by the North American Electric Reliability Corporation to ensure safety and stability.
One critical standard is a requirement that we carry operating reserves: energy we can draw on quickly or ramp down on demand to maintain stability if something goes wrong. We also maintain agreements with neighboring balancing authorities and energy markets that allow us to import or export power as needed. We collaborate, share, and support each other to ensure reliability across the region.
Our reliability also benefits from automatic protections like frequency response. If a generator or large energy user drops offline, the frequency of our grid’s alternating current adjusts automatically. That, in turn, prompts every generator on the grid to automatically adjust its output slightly to arrest that change. This is called governor response, and it’s a built-in, operator-free safeguard that reflects the shared responsibility of maintaining grid stability.
These protections, preparations, and practices ensure that our local electric reliability will not be compromised by new industries, businesses and residents who seek service in our community. TEP understands our obligation to serve local energy needs safely and reliably, and we have the skills, experience, resources and drive to keep that commitment.
We know that grid operations are complex and that our work may not always be fully understood by the public. While energy-related issues can create strong passions, we believe that conversations grounded in facts are most effective in fostering meaningful progress.
Sam Rugel is Director of System Control and Reliability at Tucson Electric Power, where he has worked for 35 years.
