Grid reliability statistics show how often customers lose electricity, how long interruptions last, and how distribution networks differ from the North American bulk power system. The figures below cover U.S. customers and state distribution systems, selected 2023–2024 regional and bulk-system measures, and individual severe events; all-event measures include major events unless stated otherwise.
Key Grid Reliability Statistics
The most useful headline figures span customer experience, severe events and bulk-system scale:
- In 2022, U.S. customers averaged 5.6 hours of electricity interruptions, including major events.
- In 2022, U.S. customers averaged 1.4 interruptions, including major events.
- From 2013 through 2022, annual interruption duration excluding major events stayed around 2 hours for U.S. customers.
- In 2022, Florida customers averaged 19.1 hours of interrupted power.
- In 2022, New Hampshire customers averaged 10.3 hours of interrupted power.
- In 2022, District of Columbia customers averaged 34 minutes of total interruptions, the shortest reported state-area average.
- In 2022, Iowa customers averaged 85 minutes of total interruptions.
- In 2024, Maine’s all-event SAIDI was 1,748.6 minutes per customer.
- In 2024, Massachusetts’ all-event SAIDI was 102.0 minutes per customer.
- In 2024, Maine recorded 2.139 all-event interruptions per customer.
- In 2024, New York recorded 0.611 all-event interruptions per customer.
- New England’s all-event SAIDI fell from 480.5 minutes in 2023 to 419.6 minutes in 2024.
- In September 2022, Hurricane Ian left more than 2.6 million Florida customers without power.
- In March 2023, an Oncor Texas disturbance affected 470,000 customers for 52 hours.
- In 2023, the North American bulk power system delivered 4,687,894 GWh of actual energy.
- In 2023, the bulk system recorded 1,071,370 MW of summer peak capacity.
- In 2023, the bulk system had 527,698 transmission circuit miles at or above 100 kV.
- In 2024, NERC counted one operator-initiated firm-load-shed incident, lasting half an hour.
Contents
- U.S. grid reliability statistics: national outage duration and frequency
- State grid reliability data: 2024 outage minutes
- State grid reliability statistics: 2024 interruption frequency
- Regional grid reliability trends in 2023 and 2024
- Severe-event grid reliability and restoration statistics
- Bulk-power grid reliability statistics: generation, transmission and security
U.S. Grid Reliability Statistics: National Outage Duration and Frequency
The U.S. national customer measures come from the Energy Information Administration’s customer-reported reliability data. In 2022, the average customer experienced 5.6 hours of interruptions and 1.4 interruptions, with major events included. EIA, “U.S. electricity customers averaged five and one-half hours of power interruptions in 2022”
Excluding major events, EIA describes average annual interruption duration as approximately consistent at around 2 hours per year from 2013 through 2022. This is a customer-level duration pattern, not a forecast, and it uses a different event scope from the all-event 2022 headline.
State variation was substantial in the 2022 EIA comparison:
- Florida customers averaged 19.1 hours of interrupted power in 2022, including major events.
- New Hampshire customers averaged 10.3 hours in 2022, including major events.
- District of Columbia customers had the shortest total interruption average at 34 minutes in 2022.
- Iowa customers averaged 85 minutes of total interruptions in 2022, among the shortest reported state averages.
These values describe electricity customers in the named geography and should not be read as a universal outage experience for every customer or as a comparison with bulk-power metrics. The EIA measure includes major events for the 2022 state averages.
State Grid Reliability Data: 2024 Outage Minutes
SAIDI measures total non-momentary interruption minutes experienced by the average distribution customer. The 2024 all-event values below include major events and are reported in minutes per customer per year by the Federal Energy Regulatory Commission.
| State | 2024 all-event SAIDI (minutes/customer) |
|---|---|
| Massachusetts | 102.0 |
| Connecticut | 153.6 |
| Illinois | 156.9 |
| Iowa | 166.7 |
| New Jersey | 174.2 |
| New York | 219.9 |
| Wisconsin | 266.1 |
| Kansas | 285.6 |
| Indiana | 312.4 |
| Pennsylvania | 336.1 |
| Michigan | 470.4 |
| Ohio | 510.5 |
| Vermont | 696.7 |
| New Hampshire | 922.7 |
| Maine | 1,748.6 |
The spread in this table is a reminder that a national average can conceal markedly different local distribution experiences. It is also an all-event comparison: a high value may reflect major-event interruptions as well as routine distribution performance. FERC, “How Affordable and Reliable is Your Power?”
State Grid Reliability Statistics: 2024 Interruption Frequency
SAIFI measures interruption count rather than total minutes. The following 2024 figures represent all-event interruptions per distribution customer per year, so frequency and duration should be read together rather than treated as interchangeable.
| State | 2024 all-event SAIFI (interruptions/customer) |
|---|---|
| New York | 0.611 |
| Connecticut | 0.644 |
| Illinois | 0.644 |
| Wisconsin | 0.729 |
| Massachusetts | 0.743 |
| Rhode Island | 0.761 |
| Iowa | 0.887 |
| New Jersey | 0.948 |
| Pennsylvania | 0.971 |
| New Hampshire | 0.985 |
| Michigan | 0.986 |
| Indiana | 0.997 |
| Ohio | 0.999 |
| Kansas | 1.003 |
| Vermont | 1.661 |
| Maine | 2.139 |
For example, Maine’s 2024 profile included both 1,748.6 SAIDI minutes and 2.139 SAIFI interruptions per customer, while New York’s included 219.9 minutes and 0.611 interruptions. Those paired observations illustrate why reliability analysis needs both how often outages happen and how long customers remain without service. FERC, “How Affordable and Reliable is Your Power?”
Regional Grid Reliability Trends in 2023 and 2024
EIA’s 2024 and 2023 distribution metrics show changes in both outage duration and frequency for New England and selected states. All values in this section include major events.
| Geography | SAIDI 2023 | SAIDI 2024 | SAIFI 2023 | SAIFI 2024 |
|---|---|---|---|---|
| New England | 480.5 minutes | 419.6 minutes | 1.398 | 1.382 |
| Connecticut | 164.6 minutes | 153.6 minutes | 0.872 | 0.876 |
| Maine | 1,863.0 minutes | 1,748.6 minutes | 3.314 | 3.636 |
New England’s all-event SAIDI declined from 480.5 to 419.6 minutes, while its SAIFI moved from 1.398 to 1.382 interruptions per customer. Connecticut’s SAIDI also declined, from 164.6 to 153.6 minutes, but its SAIFI changed from 0.872 to 0.876.
Maine’s all-event SAIDI declined from 1,863.0 to 1,748.6 minutes, while its SAIFI increased from 3.314 to 3.636. The differing directions show why a reduction in total outage minutes does not necessarily mean fewer interruptions. EIA, “Electric Power Annual, Table 11.3 Reliability Metrics Using Any Method of U.S. Distribution System by State, 2024 and 2023”
Severe-Event Grid Reliability and Restoration Statistics
Individual disturbance records are event statistics, not annual averages. Customer counts can represent a peak or event-specific affected population, and duration can differ from the timing of transmission restoration.
In 2022, major weather events affected large numbers of Florida and U.S. customers:
- Hurricane Ian left more than 2.6 million Florida customers without power in September 2022.
- Hurricane Nicole left more than 300,000 Florida customers without power in November 2022.
- Winter Storm Elliott left more than 1.5 million customers without power across several states in December 2022.
- EIA counted 18 U.S. weather-related disasters exceeding $1 billion in damage per event in 2022; this is a damage-threshold measure, not an outage count.
The EIA major-disturbance record also gives specific 2023 examples:
- A Wisconsin disturbance affecting Wisconsin and Michigan service areas lasted 8 hours 30 minutes and affected 57,000 customers on February 23, 2023.
- A Los Angeles County, California, disturbance lasted 42 hours and affected 153,555 customers on February 25–26, 2023.
- An Oncor Texas disturbance lasted 52 hours and affected 470,000 customers from March 2–4, 2023.
These records help show the scale and duration of individual events without converting them into a national reliability rate. EIA, “Electric Power Monthly, Table B.2 Major Disturbances and Unusual Occurrences”
Bulk-Power Grid Reliability Statistics: Generation, Transmission and Security
NERC’s bulk-power statistics describe a different layer from retail distribution reliability. They cover the North American bulk electric system, so the figures below should not be combined with customer SAIDI or SAIFI as if they measured the same population.
In 2023, the North American bulk power system delivered 4,687,894 GWh of actual energy and recorded 1,071,370 MW of summer peak capacity. Its transmission network included 527,698 circuit miles at or above 100 kV, and NERC counted 5,915 conventional generating units of at least 20 MW. NERC, “2024 State of Reliability”
NERC’s 2023 extreme-day analysis identified 25 extreme generation-loss days, compared with 22 in 2022. On the two highest-impact days in 2023, conventional generating-unit outages were 1.8 to 1.9 times the associated seasonal average; this is an extreme-day comparison, not an annual average. NERC, “2024 State of Reliability – Technical Assessment”
For 2024, NERC reported one operator-initiated firm-load-shed incident, caused by a failed dispatch after an unplanned Wisconsin generator outage. The load shed lasted half an hour and represented approximately 0.005% of the year, an estimate rounded by NERC for that operator-initiated event. NERC, “2025 State of Reliability – Overview”
The bulk-system incident count is not a count of all distribution outages, and a reported absence of a particular security-outage category would not establish that no attempts occurred. Taken together, these measures separate system scale, extreme generation-loss conditions and operator-initiated load shedding from the customer interruption metrics used in distribution reporting.