US EnergyData

System Average Interruption Frequency Index (SAIFI) measures the average number of interruptions that an electricity customer experiences per year. This is shown with and without major events — mostly severe weather — included.
Data source: U.S. Energy Information Administration, Form EIA-861 Annual Electric Power Industry Report
Note: Values for states are calculated as the customer-weighted averages of utility-level SAIFI. Data covers distribution-level outages only.

What this data measures

SAIFI (System Average Interruption Frequency Index) by state, showing both the figure excluding and including major event days. The gap between the two shows how much extreme events increase the number of outages customers experience.

How this data is constructed

SAIFI data are reported through the EIA Form EIA-861 Reliability Supplement. Both measures — excluding and including major event days — are compiled using the IEEE 1366 standard methodology for defining major events.

Source
U.S. Energy Information Administration, Form EIA-861 Reliability Supplement
Date range
2013–2024
Unit
Interruptions per customer per year
Last updated
Fall 2025
Next update
Annual — expected fall 2026