Power Out Map
– 0% of Union out 0 customers out in Tennessee

Power outage history

Union County Tennessee

9.2hours

without power for the average customer in a typical year, 2018–2025

14th most of 73 in Tennessee 1.4× the national median

Worst outage on record Jul 20, 2018 90% of customers out · 90% back in 3.2 hours
Hours without power, average customer per year 9.2h / yr State average 5.8 h · national median 6.6 h
Major outages a year 6.4 Peaks over 10% of customers or 50,000 customers
Typical time to restore 90% 2hours Median across major outages, from the peak
Longest single outage 2.3days Hurricane Helene, over 1% of customers out
Outage hours on storm days 33% Share falling on days with a NOAA storm report here
Worst year 2024 13 hours without power, average customer
Electricity customers 9,474 ORNL customer model · 8 well-covered years

Every day since 2015

Eleven years, one night at a time

Each cell is a day. The brighter it is, the larger the share of Union's customers who were without power at that day's worst moment.

20152016201720182019202020212022202320242025
0%100% of customers out

Year by year

Hours in the dark, per customer

2024 was the worst well-recorded year, at 13 hours for the average customer. Hatched years have a thin record and are left out of the averages.

Union, hours without power per customer

UnionUS median countyTennessee average
0 5 10 15 2.3 ’15 5.4 ’16 8.5 ’17 11 ’18 11 ’19 11 ’20 7.0 ’21 7.6 ’22 6.6 ’23 13 ’24 6.9 ’25 US 6.6 TN 5.8

The record

The biggest outages since 2015

Ranked by customer-hours lost: customers out multiplied by how long they stayed out. Times are local.

Began Storm Peak out Share Lasted 90% restored Customer-hours
Jul 20, 2018 Thunderstorms 8,546 90% 6.0 h 3.2 h 36k
Sep 27, 2024 Hurricane Helene 3,707 39% 2.3 d 1.5 h 34k
May 27, 2017 No storm report 2,349 25% 21 h 19 h 32k
Dec 24, 2020 Winter storm 1,532 16% 46 h 13 h 23k
Jun 22, 2019 No storm report 6,918 73% 15 h 6.5 h 17k
Apr 1, 2023 No storm report 1,572 17% 31 h 22 h 15k
May 17, 2025 No storm report 2,516 27% 13 h 8.0 h 12k
Jul 30, 2024 Thunderstorms 2,278 24% 17 h 13 h 11k
Jul 31, 2016 No storm report 7,509 79% 6.5 h 1.2 h 9.2k
Jul 31, 2020 Thunderstorms 1,011 11% 23 h 19 h 8.8k
May 31, 2018 Thunderstorms 1,494 16% 15 h 8.8 h 8.8k
Apr 17, 2024 No storm report 5,583 59% 2.8 h 1.5 h 8.7k

After the peak

How fast the lights come back

Each line is one major outage, from its peak. The amber line is the typical path.

0% 25% 50% 75% 100% peak+24h+48h+72h+96h half back by +4h 90% by +8h

When it happens

The outage clock

Customer-hours out by month (rings, January innermost) and local hour, 2018–2025.

00061218 Jan inside

What was happening

Weather behind the outages

Each outage is matched to NOAA storm reports for Union from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.

  • No storm on record 67%
  • Thunderstorms 20%
  • Tropical storm 8.5%
  • Winter storm 4.9%

Who keeps the lights on

Utilities serving Union

As each utility reports to the Energy Information Administration for its whole Tennessee territory, not this county alone. Outage minutes include major storm days.

Utility Type Outage min / yr Excl. major storms Outages / yr Residential ¢/kWh Customers
Knoxville Utilities Board Municipal 274 149 1.26 13.8 197k
City of Clinton Municipal 159 118 1.97 13.7 26k
Powell Valley Electric Coop Cooperative 180 162 4.59 12.2 21k
City of LaFollette Municipal 791 525 5.11 14.3 20k

EIA Form 861, latest year each utility reported. Outage minutes are SAIDI, the yearly minutes the average customer goes without power; outages a year are SAIFI.

Next door

Neighbouring counties

Across Tennessee

Where it is darkest

Hours / yr64+

All Tennessee counties →

About these numbers

Notes

Outages come from the EAGLE-I record of utility outage maps collected every 15 minutes by Oak Ridge National Laboratory. Hours without power are customer-hours divided by the county's 9,474 electricity customers. Averages use well-covered years from 2018. Outages shorter than 15 minutes, and utilities that publish no outage map, are not in the record, so these figures understate the total. How every number is made →