Extreme Heat Stresses Power Grids in Several Ways: Peak Demand, Loss of Thermal Plant Efficiency, Loss of End-Use Efficiency, Transformer Failure, and Failure to Cool Down at Night Are Stressors

      Axios’s Rebecca Falconer recently wrote two articles about the effects of extreme heat on power grids. Heat waves cause soaring power demand due to the use of air conditioning. Along with this, extreme heat reduces the efficiency of thermal power plants. It also reduces the efficiency of transmission lines. Thus, there are three major stressors. Another one is stress on equipment such as transformers. Air conditioners are also less efficient in extreme heat.

     A case in point for managing extreme heat effects on grids can be made by looking at Texas. The Electric Reliability Council of Texas (ERCOT) runs most of the state’s power grid. Seasonal power has been managed with battery expansion, mandatory weatherization, improved forecasting, and expanded demand response. In addition, data centers are required to disconnect in a controlled way during grid disturbances to help protect grid stability. Aidan Tuohy of the Electric Power Research Institute (EPRI), a nonprofit energy research and development organization, notes that diversifying power supply and storage is a key strategy for managing extreme heat events. Virtual power plants are another strategy for distributed energy resources (DERs). Well-positioned battery storage has proven to be effective in Texas and in California.

     Retired UC Berkeley electrical engineering professor Sascha von Meier told Axios that power grids are on the way to becoming more agile and flexible. She noted the following:

"We may find it no longer realistic to accommodate unlimited demand at uniform reliability across entire interconnections at a reasonable price," she says.

"Instead, we will value efficiency, flexible backup options, including storage, self-generation and microgrids, and more active management of electric demand. All the key technologies exist today."

     Rob Gramlich, president of Grid Strategies, a consulting firm focused on electric transmission, notes that a major stress on transformers and other parts of the system occurs when it fails to cool down enough at night to relieve some of that stress. This creates the need for redundancy in local distribution systems. Backup transformers can be deployed in case of failure. More storage can also be deployed to relieve potential bottlenecks.

     Power plants typically do maintenance in the shoulder seasons of spring and fall when power demand is lower. However, when those ideal times occur has been changing.

     Gramlich, who was a major spokesperson explaining during California’s 2020 rolling blackouts, notes that since then the state has relied on solar generation, which is highest during the heat of the day, and storage to add more power to the grid during extreme heat events. This has been quite successful in preventing rolling outages in recent years even as power demand has grown.

     While managing power grids in extreme heat is challenging, with good planning it can be done.  

 

References:

 

Why the US grid's extreme heat problem is changing. Rebecca Falconer. Axios. August 19, 2026. Why the US grid's extreme heat problem is changing

The grid's climate stress test. Rebecca Falconer. Axios. July 31, 2026. The US electric grid is adapting to extreme weather. Here's how