US electric distribution service outages vary by state

Recent widespread power outages in Texas are placing public and regulatory attention on the reliability of the electric grid. According to federal data, in 2019 U.S. electric distribution customers experienced an average of 4.7 hours of service interruptions -- but customers in some areas experienced more extensive outages, such as in Maine where the average total interruption time in 2019 exceeded 15 hours.

The U.S. Energy Information Administration tracks and analyzes data regarding various aspects of the nation's energy sector, including statistics describing the frequency, duration, and extent of electric distribution service outages. EIA's utility outage data can be further segmented to include or exclude outages related to "major events" such as the effects of severe weather. 

For 2019, EIA reports that "U.S. customers experienced an average of 3.2 hours of interruptions during major events and 1.5 hours of interruptions without major events, or nearly 5 hours total." With major events included, EIA reports an average total interruption of 284 minutes, which EIA described as "nearly half the average interruptions experienced in 2017, a year with more hurricanes, wildfires, and severe storms." With major events excluded, EIA reports that the average duration of interruptions customers experienced in 2019 was 92 minutes, which EIA characterized as "relatively consistent with previous years."

Source: U.S. Energy Information Administration, U.S. power customers experienced an average of nearly five hours of interruptions in 2019 (November 6, 2020).

 

According to EIA, "Many factors cause power interruptions, including weather, vegetation patterns, and utility practices." EIA also identified geographic variation among states with respect to total outage duration in 2019:

Customers in Maine, West Virginia, California, Michigan, and Mississippi experienced the longest total time interrupted in 2019. In these states, the long power interruption durations were caused by major events such as winter storms (in Maine) or wildfires (in California). In addition, Maine and West Virginia are heavily forested states where power interruptions resulting from falling tree branches are common. The average customer interruption time in these five states in 2019 ranged from almost 7 hours in Mississippi to more than 15 hours in Maine. 

Maine has previously ranked at the top of EIA's list of state average customer total outage duration per year; in 2017, EIA data showed that the average Maine customer experienced 42 hours of service interruption.

By contrast, EIA reports that electricity customers in jurisdictions including the District of Columbia, Nebraska, Arizona, Nevada, and Florida had the shortest average total time interrupted in 2019, ranging from 77 minutes in the District of Columbia to 88 minutes in Florida.