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

Power outage history

Grainger County Tennessee

6.3hours

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

25th most of 73 in Tennessee close to the national median

Worst outage on record Hurricane Helene · Sep 27, 2024 46% of customers out · 90% back in 2.3 days
Hours without power, average customer per year 6.3h / yr State average 5.8 h · national median 6.6 h
Major outages a year 3.6 Peaks over 10% of customers or 50,000 customers
Typical time to restore 90% 3hours Median across major outages, from the peak
Longest single outage 3.4days Hurricane Helene, over 1% of customers out
Outage hours on storm days 54% Share falling on days with a NOAA storm report here
Worst year 2024 23 hours without power, average customer
Electricity customers 12,567 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 Grainger'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 23 hours for the average customer. Hatched years have a thin record and are left out of the averages.

Grainger, hours without power per customer

GraingerUS median countyTennessee average
0 10 20 30 0.4 ’15 1.5 ’16 2.9 ’17 2.0 ’18 3.5 ’19 2.8 ’20 2.4 ’21 6.7 ’22 6.9 ’23 23 ’24 3.6 ’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
Sep 27, 2024 Hurricane Helene 5,826 46% 3.4 d 2.3 d 167k
Apr 1, 2023 No storm report 2,514 20% 24 h 14 h 16k
May 27, 2024 Thunderstorms 2,610 21% 12 h 7.5 h 16k
May 27, 2017 Thunderstorms 840 7% 28 h 36 h 12k
Jul 30, 2024 Thunderstorms 1,863 15% 14 h 9.0 h 11k
Jun 22, 2019 Thunderstorms 1,257 10% 18 h 11 h 10k
Dec 18, 2025 No storm report 1,443 11% 12 h 9.2 h 9.7k
May 8, 2024 Thunderstorms 1,780 14% 13 h 5.5 h 8.4k
May 17, 2025 Thunderstorms 1,946 15% 14 h 11 h 7.6k
Dec 24, 2020 Winter storm 344 3% 36 h – 7.4k
May 8, 2024 Thunderstorms 2,741 22% 6.5 h 2.8 h 6.8k
Sep 5, 2022 No storm report 466 4% 13 h – 5.8k

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 +10h

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 Grainger from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.

  • No storm on record 46%
  • Tropical storm 35%
  • Thunderstorms 16%
  • Winter storm 1.9%
  • Tornadoes 0.7%

Who keeps the lights on

Utilities serving Grainger

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
Appalachian Electric Coop Cooperative 301 215 3.20 13.6 44k
Powell Valley Electric Coop Cooperative 180 162 4.59 12.2 21k

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 12,567 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 →