A "dome" of extreme heat will send temperatures soaring in the central and eastern U.S. starting on Wednesday. More than 200 million people live in areas where temperatures are expected to exceed 90 degrees. These events can be deadly. They aim-42100508
A similar heat wave in Europe has already had severe impacts on power infrastructure over the past week. France has reduced output at its nuclear reactors, because the rivers where it discharges water used to cool the reactors are already too hot. Discharging more warm water into already-hot rivers is against environmental rules. France gets 70% of its power from nuclear energy, and is a linchpin of Europe's broader electricity grid, exporting power to countries throughout the region.
In the U.S., nuclear operators have also had to reduce output or shut down in the past because of extreme heat. Other sources of power are also vulnerable to heat waves. Natural gas turbines "become about 25% less efficient in hot weather," according to the Pacific Northwest National Laboratory, part of the Department of Energy. Turbines need oxygen to burn gas, but hot air tends to be thinner, reducing the efficiency of the turbines.
An unreliable electric grid is particularly problematic in the heat, because people blast their air conditioners and cause power usage to spike. Data centers have made the issue even more acute, and governments are now trying to figure out what to do during extreme weather events.
In the PJM electric grid area, which encompasses parts of the mid-Atlantic and Midwest, the Department of Energy gave local utilities permission to tell data centers and other large customers to use backup generation if necessary, so other customers don't get hit with outages. PJM thinks power use could approach record highs on Thursday. "We have sufficient resources to serve this level of electricity use if the generation fleet and transmission system perform as expected," the grid operator said In a statement.
Extreme weather is one of the biggest threats to data centers, researchers say. Climate risk analysis firm First Street said in a study this month that 54% of global data center capacity is "in markets facing elevated chronic heat or drought stress, while 79% is exposed to significant acute hazards such as flood, wind, or wildfire."
"For many markets, climate risk should now be considered part of the base case rather than a tail-risk scenario," the report said.
During a heat wave in 2022, Google and Oracle were forced to partially shut down data centers because their cooling systems failed. As the planet warms, the costs associated with those kinds of stresses will only grow.
Extreme weather could cost data centers $81 billion annually by 2035, because of higher cooling costs, weather-related damage and other issues, according to a World Economic Forum report last year. "Put together, our analysis of data from S&P suggests that annual climate-driven costs could reach the equivalent of 9.5% of total data center asset value by 2055 under a high-emissions scenario," the report said.
Write to Avi Salzman at avi.salzman@barrons.com
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(END) Dow Jones Newswires
June 30, 2026 15:22 ET (19:22 GMT)
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