Power outages in Illinois
In 2025, the average Illinois customer was without power for 2.4 hours (144.1 minutes) in total. That is below the US median of 4.3 hours (258.7 minutes) across the 50 states compared.
Trend
Total outage time has moved up and down since 2020, but the latest year is well below the worst one. The worst year was 2020, at 5.5 hours per customer.
Utilities in 2025
The best utility by SAIDI in 2025 was Rock Energy Cooperative, at 16.1 minutes. The worst was Southeastern IL Elec Coop, Inc, at 2,213.8 minutes (36.9 hours).
| Utility | Customers | Hours / yr | Interruptions |
|---|---|---|---|
| Southeastern IL Elec Coop, Inc | 25,031 | 36.9 | 3.9 |
| Corn Belt Energy Corporation | 37,409 | 22.7 | 7.7 |
| Egyptian Electric Coop Assn | 15,856 | 12.9 | 4.6 |
| MidAmerican Energy Co | 86,395 | 5.1 | 1.9 |
| Ameren Illinois Company | 1,251,245 | 4.8 | 1.2 |
| Southwestern Electric Coop Inc - (IL) | 24,810 | 4.0 | 1.9 |
| Eastern Illinois Elec Coop | 13,517 | 3.7 | 2.2 |
| Menard Electric Coop | 11,154 | 3.1 | 2.3 |
| Jo-Carroll Energy, Inc | 20,601 | 2.3 | 0.5 |
| Tri-County Electric Coop, Inc (IL) | 16,715 | 2.2 | 1.6 |
| City of Batavia - (IL) | 10,737 | 1.5 | 0.6 |
| Commonwealth Edison Co | 4,194,773 | 1.3 | 0.7 |
| City of Springfield - (IL) | 69,427 | 1.2 | 0.8 |
| City of St Charles - (IL) | 17,027 | 0.8 | 0.3 |
| City of Geneva - (IL) | 10,246 | 0.6 | 1.0 |
| City of Naperville - (IL) | 64,025 | 0.3 | 0.3 |
| Rock Energy Cooperative | 10,572 | 0.3 | 0.4 |
What this means for backup power
For everyday outages, enter 2.8 hours in the calculator, which is the average length of one interruption. To ride out a year like 2020, size for 5.5 hours, which is all of that year's outage hours.
FAQ
How long was the average power outage in Illinois in 2025?
One interruption lasted 2.8 hours on average. Customers had about 0.867 interruptions over the year.
What does SAIDI mean?
SAIDI is the total outage time per customer in a year. It is not the length of a single outage. In Illinois in 2025 it was 2.4 hours (144.1 minutes).
How much backup power should I plan for?
For everyday outages, plan around 2.8 hours. If you want cover for a bad year like 2020, plan for 5.5 hours of total outage time.
Utility pages
Source: U.S. EIA Form 861 Reliability file. Data snapshot 2026-11-05.