County annual report · FIPS 25017
2021 Middlesex County, MA Power Outage Report
In 2021, customers in Middlesex County, MA went without power for an average of 2.5 hours, a total of 1.1M customer-hours (Massachusetts average 7.4 hours). That ranks 10th worst of 14 Massachusetts counties and 2035th of 2,974 nationally.
Compared with MA, the US and 2020
Coverage line is EAGLE-I's share of Massachusetts customers tracked each year.
Biggest outages in Middlesex 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 | December 6, 2021 12:45 | December 8, 2021 01:00 | 1d 12h | 14,555 | 17K |
| 2 | March 1, 2021 10:30 | March 4, 2021 14:15 | 3d 3h | 14,349 | 157K |
| 3 | October 25, 2021 19:00 | October 28, 2021 15:30 | 2d 20h | 10,324 | 109K |
| 4 | September 5, 2021 06:00 | September 6, 2021 07:15 | 1d 1h | 8,416 | 9,824 |
| 5 | July 27, 2021 09:45 | July 30, 2021 14:00 | 3d 4h | 8,380 | 23K |
| 6 | June 28, 2021 09:45 | July 5, 2021 00:45 | 6d 15h | 7,590 | 69K |
| 7 | March 26, 2021 18:45 | March 27, 2021 11:45 | 17h | 5,533 | 14K |
| 8 | June 12, 2021 02:30 | June 13, 2021 11:00 | 1d 8h | 4,836 | 10K |
| 9 | February 6, 2021 10:30 | February 6, 2021 12:15 | 1h 45m | 4,746 | 3,935 |
| 10 | February 25, 2021 10:00 | February 26, 2021 21:30 | 1d 11h | 4,625 | 10K |
Outage episodes by size in 2021: 312 reached 100+ customers, 104 reached 1,000+ customers, 3 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 Middlesex 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 |
|---|---|---|---|---|---|
| Massachusetts Electric Co | 2021 | 7.9 hrs | 1.26 | 1.6 hrs | 0.94 |
| NSTAR Electric Company | 2021 | 10.7 hrs | 1.10 | 76 min | 0.73 |
| Unitil Energy Systems | 2021 | 2.3 hrs | 1.33 | 1.7 hrs | 1.04 |
| Fitchburg Gas & Elec Light Co | 2021 | 3.6 hrs | 2.79 | 77 min | 1.27 |
| Town of Reading - (MA) | 2021 | 22 min | 0.28 | 14 min | 0.25 |
| Town of Belmont - (MA) | 2018 | 57 min | 0.53 | 57 min | 0.53 |
| Massachusetts Bay Trans Authority | - | - | - | - | - |
| Town of Concord - (MA) | - | - | - | - | - |
| Town of Groton - (MA) | - | - | - | - | - |
| Town of Hudson - (MA) | - | - | - | - | - |
| Town of Littleton - (MA) | - | - | - | - | - |
| Town of Wakefield - (MA) | - | - | - | - | - |
About this data
- Outage figures come from DOE/ORNL EAGLE-I, which records customers out by county every 15 minutes. EAGLE-I tracked about 99% of Massachusetts's customers in 2021; utilities it does not see are not counted.
- Hours per customer = outage customer-minutes ÷ 434,426 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. Middlesex County has data for 2015–2025.
Cite this report
MassOutage (massoutage.com), Middlesex County, MA 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/massachusetts/middlesex-county