In-brief analysis
August 13, 2025
Even without accounting for electricity interruptions resulting from major events such as hurricanes, customers in Puerto Rico experienced on average 27 hours of power grid interruptions per year between 2021 and 2024. By comparison, electricity customers in the mainland United States generally experience about two hours of electricity interruptions per year without major events.
Hurricanes and other major events add to the outage time customers experience. In August 2024, Hurricane Ernesto affected at least 1 million customers in Puerto Rico. On average in 2024, customers in Puerto Rico went without electricity for more than 73 hours, of which 43 hours were attributed to major events such as hurricanes. In September 2022, Hurricane Fiona left all 1.5 million electricity customers in Puerto Rico without power. The average customer in Puerto Rico experienced almost 200 hours of electricity interruptions that year.
The frequency of Puerto Rico’s electricity service interruptions has generally increased since 2021. On average, electricity customers in Puerto Rico experienced 19 service interruptions in 2024: 14 without major events and 5 from major events. By comparison, electricity customers in the mainland United States experienced service interruptions 1.3 times in 2023, including days with major events. Nationwide U.S. data for 2024 is not yet available.
Beyond the impact of severe weather events like hurricanes, the frequency and length of power interruptions in Puerto Rico are linked to issues with the transmission and distribution system and generating capacity. Vegetation management is a common issue affecting transmission and distribution lines and therefore customer outages.
Puerto Rico’s electric power system largely relies on 10 electric generators fueled by petroleum liquids, natural gas, or coal that collectively provide about half of Puerto Rico’s total generating capacity. As a result, a lack of fuel supply or an unplanned outage of even one of these units can compromise the system’s reliability.
Outages are characterized by their duration and frequency and can be measured in two ways:
- The System Average Interruption Duration Index (SAIDI) measures the total duration (in hours) an average customer experiences non-momentary power interruptions in a one-year period.
- The System Average Interruption Frequency Index (SAIFI) measures the frequency of interruptions in number of occurrences.
Both metrics distinguish between days when outages are attributed to major events or not. Major events are considered 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. This distinction clarifies the grid’s reliability during routine operations.
We started collecting reliability statistics for the United States in 2013 and Puerto Rico in 2021. We provide statistics for each utility in our Annual Electric Power Industry Report. We published the preliminary version of our 2024 industry report in early August, and we plan to publish the final version in October.
Principal contributor: Lindsay Aramayo
