Blackout: Extreme Weather, Climate Change and Power Outages

Overview

Published in April 2014 by the nonprofit research group Climate Central, this 23-page report asks how much of the rise in large-scale U.S. power outages can be traced to severe weather, and what a warming climate means for the grid. Authors Alyson Kenward and Urooj Raja worked from 28 years of disturbance reports that utilities file with the U.S. Department of Energy (Form OE-417) and the North American Electric Reliability Corporation, then narrowed the core analysis to 2003 through 2012, when reporting rules were consistent.

Key Findings

• Reported major outages (those affecting at least 50,000 customers, cutting at least 300 megawatts, or forcing load shedding of 100 megawatts or more) grew roughly tenfold between the mid-1980s and 2012. Even after stricter reporting took hold in 2003, the average annual number of weather-related outages doubled.
• Of the 911 major outages analyzed for 2003-2012, 726, or 80 percent, were weather-related, and weather accounted for nearly 90 percent of all customers affected.
• More than 147 million customer accounts lost power for at least an hour because of weather during the decade, an average of about 15 million per year against a national base of roughly 145 million metered customers. Counting people rather than accounts, the authors estimate 300 million to 500 million people were affected.
• Michigan recorded the most weather-related outages with 71, followed by Texas (57), Ohio (54), and Pennsylvania and Virginia (52 each). Maryland, North Carolina, California, Illinois, and Indiana rounded out the top ten. Michigan and Texas each averaged more than 800,000 customers affected per year.
• Storms and general severe weather caused 59 percent of weather outages, cold and ice storms about 19 percent, hurricanes and tropical storms 18 percent, tornadoes 3 percent, and extreme heat and wildfire together 2 percent.
• Sixty-four percent of outages fell in the RFC and SERC reliability regions, which cover most states east of the Mississippi. The 11 western states, home to 23 percent of the population, had only 10 percent of outages.
• Citing federal and academic estimates, the report puts the cost of weather-related outages at $20 billion to $55 billion a year and notes that heavy downpours, heat waves, and strong Atlantic hurricanes have all increased, with further increases projected.

Why It Matters for Daylighting

The report’s geography lines up almost exactly with the country’s warehouse and manufacturing heartland. The Midwest, Mid-Atlantic, and Southeast concentrations of weather-driven outages cover the Ohio Valley, the I-81 and I-95 distribution corridors, Atlanta, and Dallas-Fort Worth. Owners in those regions face a rising chance that a summer thunderstorm or winter ice event will take the lights out in the middle of a shift. Toplighting through prismatic skylights gives a high-bay building a second, independent source of working light that needs no wiring, fuel, or restoration crew. Even under the heavy overcast that accompanies most of these storms, a properly sized skylight array can keep aisles and dock areas usable for safe movement and orderly shutdown.

There is a design lesson in the cause breakdown as well. Because wind, ice, and hail are the leading culprits, skylights in these markets should be specified for the loads that cause the outages in the first place: impact-resistant lenses, positive wind-uplift ratings, and curbs and flashing detailed for freeze-thaw cycles. Pairing the skylights with fall-protection screens or rated domes keeps the roof safe for the maintenance crews who will be up there after every storm.

About the Source

Climate Central is an independent, nonprofit science and journalism organization based in Princeton, New Jersey; it publishes peer-reviewed research and does not lobby or endorse legislation. This report was written by Alyson Kenward, PhD, and Urooj Raja and released in 2014, running 23 pages with references and acknowledgments to reviewers at Lawrence Berkeley National Laboratory and Iowa State University. The full report, including state and utility rankings and regional charts, is available directly from Climate Central.