More than one million customers — 73% of the island’s total — are without power five days after Hurricane Fiona hit Puerto Rico. This comes just five years after Hurricane Maria caused long-lasting power outages across the U.S. territory.
A number of blackouts have been caused by recent years’ extreme weather events, including heat waves in California and the “polar vortex” in Texas. Extreme weather can cause the power to go out when power lines get knocked down by strong winds, and when transmission equipment freezes or overheats or floods.
And a new study demonstrates that it’s not just anecdotal evidence: Weather-related power outages are becoming more frequent because of climate change.
The research organization Climate Central released a report last week that analyzes the major electricity outages in the United States since 2000. The two key findings are that most of these events are caused by extreme weather, and as extreme weather becomes more common because of climate change, so do the power outages.
Of course, the resilience of the infrastructure itself plays a key role. Many of the regions that have suffered the most also have electric grids prone to failure, without the backup capacity and delivery mechanisms to overcome these challenges. All signs are that extreme weather events will continue to batter electric grids, plunging vulnerable areas into darkness.
From 2000 to 2021, 1,542 weather-related major power outages were reported by U.S. utilities, roughly 83% of them attributed to weather-related events. Those blackouts have become more frequent in recent years.
“The average annual number of weather-related power outages increased by roughly 78% during 2011-2021, compared to 2000-2010,” Climate Central writes.
The rate of failures is speeding up: There have been about 73 power outages annually on average in this century, but there were 150 — more than twice the annual average — in 2021.
Winter weather such as snow, ice and freezing rain was responsible for 22% of the outages since 2000, and 15% were caused by hurricanes and tropical storms. Fifty-eight percent were caused by other kinds of severe weather, such as high winds, thunderstorms and heavy rain.
Extreme heat caused only 2% of outages and only 2.4% were attributed to wildfires, but that category is growing rapidly, as the West has experienced a series of unusually severe wildfire seasons. Nearly two-thirds (65%) of wildfire-related outages have occurred in the last five years.
The region with the most weather-related outages was the Southeast, followed by the Midwest and the Northeast.
While the Southeast has always been threatened by heat waves and hurricanes, climate change has brought more extreme winter weather to a region without the infrastructure for it. Climate change is also weakening the planet’s jet stream, causing it to dip further south, bringing a band of cold air just north of it. In January, this phenomenon and the climate change-related stretching out of the polar vortex brought a snowstorm to the Carolinas, leaving tens of thousands of customers without electricity as power lines went down.
The same phenomenon happened a year earlier, when the February 2021 winter storm and cold spell caused nearly 10 million people in the South to lose power, with especially long-lasting blackouts in Texas.
Texas and California have both seen a notable uptick in weather-related power outages in the last few years. Texas experienced 80 weather-related blackouts from 2019 to 2021. “This three-year period accounts for 44% of Texas’s total weather-related outages since 2000,” the report notes. “Severe or winter weather caused the majority of these outages (76%), followed by hurricanes (21%).”
It’s a similar story in California: 44 power outages from 2019 to 2021, with those three years responsible for more than one-third of the state’s total weather-related outages since 2000. This is partly because of the increased prevalence of wildfires, which caused 14 of California’s outages in the last three years.
It’s not only states experiencing extremes of heat and cold that are vulnerable. In terms of blackouts, last year was the worst for Michigan, with 14. That state has been pummeled by heavy storms in recent years, as climate change causes precipitation to be more concentrated in extreme events.
Climate Central advises states to prepare for extreme weather by building more resilient power systems. Texas’s problems in 2021 were caused in part by a failure to weatherize its power infrastructure. Extreme cold wasn’t a problem in Texas, until it was. Distributed systems are also more resilient, because a problem in one place does not take down the whole system. Climate Central advises utilities to break communities into “self-sufficient energy systems with a smaller, distinct geographic footprint,” known as microgrids.