In-brief analysis
August 10, 2026
Data source: U.S. Energy Information Administration, Annual Electric Power Industry Report
Data values: Reliability—2025 Data Early Release
Note: The System Average Interruption Duration Index (SAIDI) shown here measures the total duration (in hours) of non-momentary power interruptions an average customer experiences in a one-year period. This metric distinguishes Major Event Days (MED), which is defined by the IEEE Standard 1366 as a day whenever the daily system exceeds a predefined threshold measured in minutes per day and based on data from the previous five years.
In 2025, customers in Puerto Rico experienced an average of 36 hours of power interruptions that were not caused by major events such as hurricanes, 19% more than in 2024. On average, between 2021 and 2025, Puerto Rican customers experience 29 hours of power loss each year. By comparison, electricity customers in the mainland United States generally experience about two hours of electricity interruptions per year without major events.
The length of power interruptions without major events in Puerto Rico has increased since 2023. In 2025, major events resulted in Puerto Rican customers experiencing an additional 23 hours of power interruptions.
Major events are events beyond the electric utility’s normal operating conditions and can include severe weather, interference from vegetation near power lines, and some utility practices that fall outside the scope of what is considered normal for a given utility. A Major Event Day (MED) is defined as any day during which the average duration of power outages exceeds a predefined threshold, based on data from the previous five years of the system. This distinction clarifies the grid’s reliability during routine operations.
There were no major hurricanes directly affecting Puerto Rico in 2025. However, other events contributed to the 23 hours of MED power interruptions, including heavy rainfall and flooding, particularly between April and May of last year. This includes Hurricane Erin, which didn’t hit Puerto Rico directly but brought tropical storm-force winds, landslides, and downed trees, affecting the island’s grid and other infrastructure.
Data source: U.S. Energy Information Administration, Annual Electric Power Industry Report
Note: The System Average Interruption Frequency Index (SAIFI) measures the frequency of interruptions in number of occurrences. This metric also distinguishes between days when outages are attributed to major events or not.
Another measure of reliability is the annual frequency of power interruptions. Without accounting for MEDs, the frequency of Puerto Rico’s electricity service interruptions has doubled since 2021 and increased 13% between 2024 and 2025. On average, a customer in Puerto Rico experienced almost 16 interruptions in 2025. That number increases to about 17 interruptions when accounting for days with major events.
Principal contributor: Lindsay Aramayo
