Solar energy and battery technologies are helping utilities manage increased electricity demand during extreme heat events. However, prolonged high temperatures are revealing vulnerabilities within the electrical grid. Electricity demand rises as air conditioning units operate more intensively in hot weather, while high temperatures can reduce the efficiency of various components of the system and place additional stress on equipment.
Michael Webber, a mechanical engineering professor at the University of Texas at Austin, noted that grid operators encounter a 'triple whammy' during extreme heat, as air conditioners, transmission lines, and power plants all operate less efficiently. He stated, 'At the times we need the grid the most is when every single component in the grid is less efficient ... but also more fragile, and then we run it more.' A 2018 study co-authored by Webber indicated that power plants, air conditioners, and transmission systems tend to function more efficiently at cooler temperatures.
Hot nights can also hinder equipment from cooling down, with Webber emphasizing that in Texas, the issue arises not only from high daytime temperatures but also from insufficient nighttime cooling. Rob Gramlich, president of Grid Strategies, highlighted that local distribution systems, including transformers, require time to cool overnight, and utilities may need to enhance redundancy in these networks and invest in backup transformers to address equipment failures.
Longer hot seasons may also reduce the traditional spring and fall maintenance windows for power plants. A 2024 study co-authored by Webber found that the period of mild spring weather in Texas has shifted earlier by 2.4 days per decade since 1959, while the fall period has shifted later by 1.1 days per decade. The researchers predict that these windows will converge around December and January by the mid-2040s, which could complicate maintenance during extreme weather events.
California's experience illustrates how the reliability of the grid can change rapidly with the integration of solar and storage solutions. The state faced rolling blackouts during the summer heat of 2020 but has since improved its situation significantly. As of July, clean energy met or exceeded demand on California's main grid for an average of 6.8 hours per day, a notable increase from 0.4 hours in 2022.
While solar and storage advancements help manage summer peaks, prolonged heat presents ongoing challenges for maintaining the grid's efficiency and reliability over extended periods.