UniSource Achieves Best-Ever Reliability Performance, Continuing Nation-Leading Results
With summer on the way, customers across Arizona know they can count on a few things: hot weather, beautiful desert sunsets, and top-tier reliability from UniSource Energy Services.
Last year, our customers experienced just 64 minutes without power on average over the course of the year – one of UniSource’s best reliability results on record. We use this metric, the System Average Interruption Duration Index (SAIDI), to measure our reliability against other energy providers.
Our 2025 score compares favorably to a nationwide average above 100 minutes and is comparable to the 60 minutes we achieved in 2024. It’s also among the top quartile of results aggregated annually by the Edison Electric Institute.
Our strong SAIDI scores reflect the impact of sustained investments, careful planning, and continuous improvement across our system.
“We know our customers count on us to power their everyday lives. If we’re doing our jobs well, the lights go on, homes stay comfortable and things work,” said Director June Deering. “Our values and our culture place a focus on safety, continuous improvement and innovation. We’re really proud of our crews’ efforts to ensure grid resiliency and dependability, even as we work to balance affordability and long-term sustainability.
What’s behind our reliability
Targeted investment. UniSource continues to invest in maintaining and strengthening its local energy grids, following rigorous maintenance practices designed to support dependable service.
Planning. Each year, we prepare for extreme summer heat, monsoon weather and seasonal temperature swings to reduce the risk of outages before they occur.
Preparedness. Ongoing maintenance and key prevention programs help us achieve high reliability. UniSource uses multiple methods to assess needed improvements and upgrades, including ground patrols and aerial inspections of power lines, monitoring of substation equipment, and careful analysis of distribution circuits.
Sustainability with reliability. UniSource is committed to serving customers with a balanced, all-of-the-above energy portfolio that maintains reliability and affordability while supporting long-term emissions reductions.
Customer communication. We’re continuing to improve communication about the few outages that do occur through texts, emails and push notifications. Help us reach you when it matters most by updating your contact information on My Account.
