County annual report · FIPS 17031
2015 Cook County, IL Power Outage Report
In 2015, customers in Cook County, IL went without power for an average of 1.6 hours, a total of 3.4M customer-hours (Illinois average 2.3 hours). That ranks 62nd worst of 100 Illinois counties and 1420th of 2,484 nationally.
Compared with IL, the US
Coverage line is EAGLE-I's share of Illinois customers tracked each year.
Biggest outages in Cook County, 2015
The 10 outage episodes with the most customers out at once. Times are UTC.
| # | Started (UTC) | Ended (UTC) | Duration | Peak out | Customer-hours |
|---|---|---|---|---|---|
| 1 | March 11, 2015 10:00 | March 13, 2015 10:30 | 2d | 144,538 | 46K |
| 2 | July 19, 2015 03:00 | August 4, 2015 17:45 | 16d 14h | 38,285 | 667K |
| 3 | August 5, 2015 04:30 | August 26, 2015 11:00 | 21d 6h | 13,374 | 286K |
| 4 | July 7, 2015 03:15 | July 19, 2015 01:45 | 11d 22h | 12,984 | 248K |
| 5 | December 23, 2015 11:30 | December 26, 2015 00:00 | 2d 12h | 10,081 | 43K |
| 6 | September 8, 2015 12:00 | September 13, 2015 10:00 | 4d 22h | 9,284 | 60K |
| 7 | April 28, 2015 11:30 | April 30, 2015 07:30 | 1d 20h | 9,160 | 9,259 |
| 8 | January 31, 2015 12:00 | February 8, 2015 07:30 | 7d 19h | 8,698 | 132K |
| 9 | November 11, 2015 12:00 | November 18, 2015 15:00 | 7d 3h | 8,661 | 109K |
| 10 | September 14, 2015 12:30 | September 22, 2015 05:00 | 7d 16h | 8,659 | 155K |
Outage episodes by size in 2015: 118 reached 100+ customers, 86 reached 1,000+ customers, 5 reached 10,000+ customers.
Utility reliability filed with the EIA
SAIDI (average outage time per customer) and SAIFI (average interruptions per customer) that utilities serving Cook County reported on EIA Form 861 for 2015, or their most recent earlier filing. Utility-wide figures, not county-specific.
| Utility | EIA year | SAIDI | SAIFI | SAIDI excl. major events | SAIFI excl. major events |
|---|---|---|---|---|---|
| Commonwealth Edison Co | 2015 | 1.8 hrs | 0.97 | 72 min | 0.86 |
| Northern Indiana Pub Serv Co | - | - | - | - | - |
| University of Illinois | - | - | - | - | - |
| Village of Winnetka - (IL) | - | - | - | - | - |
About this data
- Outage figures come from DOE/ORNL EAGLE-I, which records customers out by county every 15 minutes. EAGLE-I tracked about n/a of Illinois's customers in 2015; utilities it does not see are not counted.
- Hours per customer = outage customer-minutes ÷ 2,162,007 customers (ORNL modeled county customer count), including major storm days. It is comparable across counties but is not the SAIDI a utility files.
- An outage event is a continuous stretch with customers out; counts at 100, 1,000 and 10,000+ use its peak.
- Years loaded: 2015–2025. Cook County has data for 2015–2025.
Cite this report
MassOutage (massoutage.com), Cook County, IL annual power outage report, 2015, data as of Oct 3, 2026 02:41 UTC, sources: DOE EAGLE-I (https://eagle-i.doe.gov/); EAGLE-I modeled customer counts (MCC) (https://figshare.com/); EIA Form 861 (utility reliability) (https://www.eia.gov/electricity/data/eia861/). https://massoutage.com/reports/2015/illinois/cook-county