County annual report · FIPS 13067
2021 Cobb County, GA Power Outage Report
In 2021, customers in Cobb County, GA went without power for an average of 0.9 hours, a total of 299K customer-hours (Georgia average 2.4 hours). That ranks 138th worst of 159 Georgia counties and 2691st of 2,974 nationally.
Compared with GA, the US and 2020
Coverage line is EAGLE-I's share of Georgia customers tracked each year.
Biggest outages in Cobb County, 2021
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 27, 2021 09:30 | March 27, 2021 17:00 | 7h 30m | 21,747 | 5,829 |
| 2 | September 26, 2021 01:30 | September 26, 2021 10:15 | 8h 45m | 21,079 | 5,411 |
| 3 | March 1, 2021 09:45 | March 1, 2021 23:15 | 13h 30m | 5,857 | 16K |
| 4 | August 14, 2021 22:00 | August 15, 2021 14:15 | 16h 15m | 4,864 | 3,873 |
| 5 | October 13, 2021 13:45 | October 14, 2021 00:15 | 10h 30m | 3,834 | 3,527 |
| 6 | March 25, 2021 13:15 | March 25, 2021 23:00 | 9h 45m | 3,324 | 3,776 |
| 7 | July 22, 2021 09:00 | July 23, 2021 04:00 | 19h | 3,172 | 2,233 |
| 8 | August 4, 2021 01:45 | August 5, 2021 05:00 | 1d 3h | 2,996 | 3,245 |
| 9 | February 1, 2021 13:00 | February 2, 2021 03:45 | 14h 45m | 2,950 | 1,147 |
| 10 | May 28, 2021 17:45 | May 30, 2021 02:30 | 1d 8h | 2,874 | 7,756 |
Outage episodes by size in 2021: 130 reached 100+ customers, 46 reached 1,000+ customers, 2 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 Cobb County reported on EIA Form 861 for 2021, 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 |
|---|---|---|---|---|---|
| Georgia Power Co | 2021 | 2.4 hrs | 1.28 | 2.4 hrs | 1.25 |
| GreyStone Power Corporation | 2021 | 2.9 hrs | 1.70 | 1.5 hrs | 1.28 |
| Cobb Electric Membership Corp | 2021 | 28 min | 0.58 | 28 min | 0.58 |
| City of Marietta - (GA) | 2021 | 66 min | 1.06 | 64 min | 0.94 |
| City of Acworth - (GA) | - | - | - | - | - |
About this data
- Outage figures come from DOE/ORNL EAGLE-I, which records customers out by county every 15 minutes. EAGLE-I tracked about 90% of Georgia's customers in 2021; utilities it does not see are not counted.
- Hours per customer = outage customer-minutes ÷ 322,249 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. Cobb County has data for 2015–2025.
Cite this report
MassOutage (massoutage.com), Cobb County, GA annual power outage report, 2021, 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/2021/georgia/cobb-county