Sullivan County Power Outage History
2014–2025 · Tennessee
Average — typical outage frequency and duration nationally. How grades are calculated
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Sep 27, 2024 | 130 hrs | 21,584 (26%) | Tropical Storm Helene |
| Jan 3, 2023 | 8 hrs | 15,053 (18%) | Thunderstorm Wind |
| Jul 29, 2023 | 48 hrs | 12,565 (15%) | Thunderstorm Wind |
| Jul 21, 2018 | 47 hrs | 12,117 (14%) | Thunderstorm Wind |
| Dec 9, 2018 | 76 hrs | 7,445 (9%) | Heavy Snow |
Over the 12 years from 2014 to 2025, Sullivan County recorded 916 distinct power outage events, averaging 3.0 hours per event.
The single worst outage on record in Sullivan County started September 27, 2024 (Tropical Storm Helene), lasting 130 hours and leaving up to 21,584 customers without power (26% of the county) at its peak.
July has historically been the worst month for outages in Sullivan County, with 114 events recorded during that month across the dataset.
Based on this history, Sullivan County earns a Reliability Grade of C, placing it in the 55th percentile nationally for grid reliability (higher percentile = more reliable).
Sized for Sullivan County's outage profile
See more picks in our Best Dual-Fuel Portable Generators for Power Outages roundup.
Champion Power Equipment 4375-Watt Dual Fuel RV Ready Portable Generator with Free 3-Year Warranty
Outage-prep kit
See our outage-prep guides.
Similar counties in Tennessee
Counties with the closest reliability grade and national percentile to Sullivan County.
| County | Grade | National percentile |
|---|---|---|
| Robertson County | C | 53rd |
| Trousdale County | C | 52nd |
| Blount County | C | 52nd |
| Knox County | C | 52nd |
| Cumberland County | C | 52nd |
FAQ
How often does power go out in Sullivan County?
Between 2014 and 2025, Sullivan County recorded 916 outage events, averaging 3.0 hours each.
What is Sullivan County's reliability grade?
Sullivan County has a Reliability Grade of C, in the 55th national percentile.
What was the worst power outage in Sullivan County?
The worst outage on record started September 27, 2024 (Tropical Storm Helene), lasting 130 hours and affecting up to 21,584 customers.