Heat Season Power Outages

Click to download custom graphics

Click to download custom graphics

Click to download custom graphics

Click to download custom graphics

KEY CONCEPTS

• Power outages and hot weather are a dangerous mix. When blackouts overlap with the need to cool homes, schools, and businesses, the risks compound for heat-sensitive populations. 

• Climate Central assessed the rising risk of weather-related power outages during heat season (May-September) from 2000 to 2023.

• The U.S. experienced about 60% more heat season power outages during the last 10 years (2014-2023) than during the first 10 years analyzed (2000-2009). 

• The South faces more heat season power outages than any other region — followed closely by the Southeast, Northeast, and Ohio Valley.

• Texas and Michigan led all other states in total heat season outages.

Download data

Power outages and hot weather: a dangerous mix

Weather-related power outages are rising as many types of extreme weather become more frequent and/or intense in our warming climate.

When blackouts overlap with extreme heat and the need to cool homes, schools, and businesses, the risks compound — especially for heat-sensitive populations including children and the elderly.  

This happened recently in the aftermath of Hurricane Beryl, which downed power lines and left millions of people in Houston without electricity or air conditioning while the city suffered a dangerous heat wave. 

This scenario could become increasingly common with more compound extreme events in our warming climate. According to a 2022 study, hurricane-induced blackouts followed by heat waves in the Houston area could increase dramatically if high levels of heat-trapping emissions continue and grid resilience doesn’t improve. 

Studies suggest that major U.S. cities are not prepared for more overlapping power outages and extreme heat. 

In Atlanta, Detroit, and Phoenix, between 68% and 100% of the population would face elevated risk of heat exhaustion or heat stroke during a combined blackout and heat wave. Such events could more than double rates of heat-related mortality in all three cities. 

Climate Central assessed the rising risk of weather-related power outages during hot weather across the U.S.

Heat season power outages rising

Climate Central analyzed data on major U.S. power outages due to weather from 2000 to 2023. Major outages are events that affect at least 50,000 customers (homes or businesses) or interrupt service of 300 megawatts or more.

This analysis considers weather-related outages that occurred between May and September (“heat season”), when heat risk is elevated and cooling demand (measured in cooling degree days) peaks annually. See Methodology for details. 

The data show that weather-related power outages during heat season are on the rise. 

The U.S. experienced about 60% more heat season power outages during the last 10 years (399 events from 2014-2023) than during the first 10 years analyzed (245 events from 2000-2009). 

Heat season outages accounted for nearly half (47% or 831) of all 1,755 weather-related outages during the 2000-2023 period. 

Most heat season outages in the South

The number of heat-season outages varies among U.S. regions — reflecting the weather each region experiences as well as differences in population density and grid vulnerability. 

Since 2000, the South has experienced more heat season power outages than any other region — followed closely by the Southeast, Northeast, and Ohio Valley. 

The Northwest, Southwest, and Northern Rockies and Plains all experienced less than one-quarter of the total heat season power outages in any other region. 

Most heat season outages in Texas and Michigan

Texas had the most heat season outages of any other state (107 events), accounting for 61% of all such events across the South. 

Michigan followed with 90 heat season outages, accounting for 74% of all such events in the Upper Midwest. 

According to the U.S. Energy Information Administration, the majority of households in Texas and Michigan (95% and 87%, respectively) use air conditioning. 

Dangers of losing power during heat season

The dangers of power outages and extreme weather multiply when they happen together. From 2018 to 2020, 62% of lengthy U.S. power outages overlapped with extreme weather events — especially extreme heat, heavy rainfall, and hurricanes. 

Power outages are more than just an inconvenience. A lack of refrigeration, heating, and air conditioning can be dangerous or even deadly, especially during extended outages. Outages can also lead to a range of potential health consequences, particularly for those who rely on electricity for critical medical equipment. 

Heat waves bring increased electricity demand for cooling, which can overload the power grid, further exposing grid vulnerabilities in our warming climate. Overlapping outages and extreme heat can ​​expose people to dangerous temperatures and amplify health risks. Such events affect the entire country. A recent study shows that widespread extreme heat has coincided with power outages in every U.S. region from 2012 to 2021. 

Older people and individuals with disabilities or certain health conditions may be especially vulnerable during weather-related power outages. Consequences can be compounded by the precipitating events, such as flooding, wildfire, or extreme temperatures. 

Longer outages amplify health risks for vulnerable populations. A 2023 study of major hurricane-induced outages in the Southeast from 2017 to 2020 found that economically and socially vulnerable counties face significantly longer wait times for the power to come back on. 

A 2023 study found that long-duration (eight-hour or longer) outages were most prevalent across the Northeast, South, and Appalachia from 2018 to 2020. Arkansas, Louisiana, and Michigan in particular experienced significantly more long-duration outages in counties with large socially- and medically-vulnerable populations.   

The impacts of power outages and lengthy restoration times can disproportionately burden people of color, as during the February 2021 Texas cold outbreak; the aftermath of Hurricane Maria in Puerto Rico; and power restoration in Florida after Hurricane Irma. 

Building a more resilient grid

The rising risks of weather-related power outages reflect the hazards of a 20th century power grid operating in the 21st century climate. 

Upgrading the nation’s electrical infrastructure to become more resilient and reliable will be expensive and challenging. Ultimately, rapidly cutting emissions is the most meaningful action to slow the rate of warming, which can ease mounting stress on our power grid and allow more time to adapt our systems to a changing climate. 

In the near-term, there are promising and innovative solutions to build electricity security now.

• Microgrids are self-sufficient energy systems with a smaller, distinct geographic footprint, such as a college campus, hospital complex, or neighborhood. Their relatively small scale also makes microgrids more easily powered by renewable energy sources like solar and wind power, which has the added benefit of reducing emissions from power generation.

• Smart grid technologies include sensors that allow operators to assess grid stability and provide consumers with better information about outages.

• Hardening the grid refers to measures that fortify the system against damage. This can include tree trimming along power lines, replacing wooden electrical poles with steel or concrete, and burying overhead transmission lines.

• Incentives can further encourage customers to cut back on usage during peak times.

LOCAL STORY ANGLES

Assess weather-related energy risks in your state or region

The U.S. Energy Information Administration’s Energy Disruptions Maps help identify local risks to energy infrastructure from tropical storms, wildfire, and flooding. Local utility companies often provide current power outage maps and updates by zip code. 

Are people and facilities in your area prepared for power outages?

Each spring, the North American Electric Reliability Corporation publishes a Summer Reliability Assessment that covers grid reliability, preparedness, and associated risks that could impact U.S. regions over the upcoming summer. Review the 2024 Summer Reliability Assessment to assess short- and long-term (10-year) risks in your region. 

Preparedness and safety guidance for power outages are available from the Federal Emergency Management Agency and the Centers for Disease Control and Prevention — including specific guidance for outages during extreme heat. 

CONTACT EXPERTS

Costa Samaras, Ph.D. (he/him)
Director, Wilton E. Scott Institute for Energy Innovation
Carnegie Mellon University
Relevant expertise: Climate-resilient energy systems and pathways to net-zero emissions. Former Biden-Harris White House OSTP Chief Advisor for the Clean Energy Transition
Contact: csamaras@cmu.edu

Brian Stone, Jr., Ph.D.
Professor, School of City & Regional Planning
Georgia Institute of Technology
Relevant expertise: Power outages and heat wave risk in cities
Contact: brian.stone@design.gatech.edu

FIND EXPERTS

Submit a request to SciLine from the American Association for the Advancement of Science or to the Climate Data Concierge from Columbia University. These free services rapidly connect journalists to relevant scientific experts. 

Browse maps of climate experts and services at regional NOAA, USDA, and Department of the Interior offices.  

Explore databases such as 500 Women Scientists, BIPOC Climate and Energy Justice PhDs, and Diverse Sources to find and amplify diverse expert voices. 

Reach out to your State Climate Office or the nearest Land-Grant University to connect with scientists, educators, and extension staff in your local area. 

METHODOLOGY

Power outage data from 2000 to 2023 were collected from the U.S. Department of Energy’s Form OE-417 reports. Major outages are events that affect at least 50,000 customers (homes or business) or interrupt service of 300 megawatts or more. We consider only power outages (including blackouts and voltage losses), fuel supply emergencies, and emergency appeals for reduced electricity usages where there was a reported number of customers affected or power lost — and where outages were attributed to weather- or wildfire-related causes. We do not include reports of vandalism or cyber-attacks. 

Heat season power outages refer to weather-related major power outages that occurred between May and September — the annual period when cooling degree days (a temperature-based indicator of cooling demand) peak nationally and in major regions of the contiguous U.S. 

Utilities may report weather-related event causes as storms or severe weather, which may refer to a broad range of conditions; these conditions may not meet meteorological criteria for severe weather. Climate Central analysts reviewed report details and relevant media coverage to appropriately assign documented weather events to individual outages. Power outages that affected multiple states and regions were counted in each state and region's total number of events, but were counted only once in the national number of events. Regions were defined based on NOAA’s U.S. Climate Regions.