The rise of extreme weather-related power outages in California

Data: Climate Central via U.S. Department of Energy; Note: Major power outages affect at least 50k customers or interrupt service of 300 megawatts or more; Outage events can cross state lines; Map: Kavya Beheraj/Axios

California's electric grid could face increasing strain as climate change raises the frequency and severity of extreme weather events, a new study indicates.

Why it matters: Outages, and lengthy restore times, can cost the economy billions of dollars and lead to loss of life. Just two months ago, a severe storm left more than 700,000 Bay Area customers without power and was blamed for at least three deaths .

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By the numbers: Extreme weather accounted for almost 61% of all major outages in California from 2000 to 2023, according to nonprofit research and communications group Climate Central.

• Such outages are defined as affecting at least 50,000 homes or businesses or as cutting service of at least 300 megawatts.

State of play: For PG&E, one of the state's largest electric utility companies, 2023 was the "most impactful year on record" in terms of weather-related outages, spokesperson Tamar Sarkissian said in an emailed statement.

• Based on records dating back to 1995, "four of the five years where weather caused the most outages have happened since 2017," according to Sarkissian.
• Winter storms tend to have the most impact on the grid, followed by heat waves, per Sarkissian.

Zoom out: Wildfires and heat waves , two of the hazards most clearly linked to human-caused climate change , are becoming more problematic, Climate Central found.

• Extreme heat accounts for a smaller share of outages but creates acute public health hazards when it does occur.
• Wildfires accounted for about 2% of weather-related outages in the U.S. during this period, with more than half occurring during the past five years. Some were preemptive safety shut-offs by utilities to try to avoid sparking a blaze on days with extreme fire weather conditions.

Yes, but: Patrick Brown, co-director of the climate and energy team at the Berkeley-based Breakthrough Institute, told Axios via email that it's difficult to directly attribute increased outages to extreme weather "without first establishing that the supposed driving weather phenomena is actually changing sufficiently."

• "This is because so many other aspects of electricity grids (infrastructure, power supply, power demand) are changing," Brown added.
• That's something Jen Brady, a researcher at Climate Central and main author of the report, noted as well — other factors include the age and load placed on parts of the grid, in addition to population growth.

What they're saying: While extreme heat and wildfires have increased in California, high winds from winter storms are responsible for a larger proportion of outages, Brown said.

• The Bay Area, however, should prepare for higher electricity demand as it gets hotter, which will lead to greater use of air conditioning and more preemptive safety shut-offs during fire weather, he added.

What's next: With the increasing recognition that America's power capacity has to grow to support generative artificial intelligence and other high-tech applications, utilities are rethinking their architecture and upgrades schedule.

• Sarkissian noted that PG&E is training machine learning models on historical data to better understand the relationship between weather and outages.