County annual report · FIPS 46103
2021 Pennington County, SD Power Outage Report
In 2021, customers in Pennington County, SD went without power for an average of 3.8 hours, a total of 258K customer-hours (South Dakota average 3.4 hours). That ranks 20th worst of 61 South Dakota counties and 1593rd of 2,974 nationally.
Compared with SD, the US and 2020
Coverage line is EAGLE-I's share of South Dakota customers tracked each year.
Biggest outages in Pennington 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 13, 2021 00:45 | March 15, 2021 15:45 | 2d 15h | 3,084 | 11K |
| 2 | February 12, 2021 01:45 | February 12, 2021 05:30 | 3h 45m | 2,912 | 4,336 |
| 3 | December 3, 2021 16:00 | December 3, 2021 20:45 | 4h 45m | 2,564 | 665 |
| 4 | October 12, 2021 13:30 | October 14, 2021 00:30 | 1d 11h | 2,487 | 12K |
| 5 | April 7, 2021 01:45 | April 7, 2021 14:00 | 12h 15m | 2,103 | 5,785 |
| 6 | September 3, 2021 14:15 | September 7, 2021 13:00 | 3d 22h | 1,321 | 120K |
| 7 | November 22, 2021 15:00 | December 1, 2021 07:00 | 8d 16h | 1,132 | 10K |
| 8 | July 21, 2021 14:45 | July 21, 2021 16:15 | 1h 30m | 850 | 492 |
| 9 | March 29, 2021 11:00 | March 30, 2021 00:30 | 13h 30m | 763 | 2,098 |
| 10 | July 6, 2021 15:00 | July 15, 2021 15:45 | 9d | 760 | 41K |
Outage episodes by size in 2021: 55 reached 100+ customers, 7 reached 1,000+ customers, 0 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 Pennington 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 |
|---|---|---|---|---|---|
| Black Hills Power, Inc. | 2021 | 2.6 hrs | 1.17 | 41 min | 0.32 |
| Black Hills Electric Coop, Inc | 2021 | 6.6 hrs | 1.67 | 2.2 hrs | 1.02 |
| West River Electric Assn Inc | 2021 | 54 min | 0.72 | 54 min | 0.72 |
| WAPA-- Western Area Power Administration | - | - | - | - | - |
| Black Hills Energy | - | - | - | - | - |
About this data
- Outage figures come from DOE/ORNL EAGLE-I, which records customers out by county every 15 minutes. EAGLE-I tracked about 79% of South Dakota's customers in 2021; utilities it does not see are not counted.
- Hours per customer = outage customer-minutes ÷ 68,130 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. Pennington County has data for 2015–2025.
Cite this report
MassOutage (massoutage.com), Pennington County, SD 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/south-dakota/pennington-county