Power outages in Wyoming
In 2025, the average Wyoming customer had 261.7 minutes (4.4 hours) without power over the year. That is slightly above the US median of 258.7 minutes (4.3 hours) across 50 states compared.
Trend
Outage time fell from 289.7 minutes in 2020 to a low of 127.0 minutes (2.1 hours) in 2023, then rose again to 261.7 minutes in 2025. The worst year was 2020, at 4.8 hours.
Utilities in 2025
Cheyenne Light Fuel & Power had the lowest SAIDI in 2025 at 53.5 minutes (0.9 hours). Powder River Energy Corp had the highest at 570.9 minutes (9.5 hours).
| Utility | Customers | Hours / yr | Interruptions |
|---|---|---|---|
| Powder River Energy Corp | 27,766 | 9.5 | 3.5 |
| Montana-Dakota Utilities Co | 18,396 | 5.9 | 1.8 |
| High Plains Power Inc | 14,035 | 5.3 | — |
| PacifiCorp | 148,217 | 3.3 | 1.4 |
| Cheyenne Light Fuel & Power | 50,163 | 0.9 | 0.8 |
What this means for backup power
For everyday outages, enter 2.5 hours in the calculator, which is the average length of one interruption. To ride out a year like 2020, size for 4.8 hours, the total outage time across that whole year.
FAQ
What does SAIDI mean for my home?
SAIDI is the total time the average customer is without power in one year. In Wyoming in 2025 it was 4.4 hours. It is not the length of a single outage.
How long does one outage last in Wyoming?
One interruption lasts about 2.5 hours on average. Customers had about 1.7 interruptions per year in 2025.
How much backup power should I plan for?
For typical outages, plan for about 2.5 hours. If you want cover for a year as bad as 2020, plan for 4.8 hours. The calculator on this page can help you size a system for either figure.
Utility pages
Source: U.S. EIA Form 861 Reliability file. Data snapshot 2026-11-05.