The real reason a heat wave is pushing California’s power grid to its limits

Heat’s impact on the grid is twofold, explained Eric Fournier, research director at UCLA’s Institute of the Environment and Sustainability. First, more people turn on their air conditioners and run them for longer on hot days, which means electricity demand is higher.

Second, heat has a physical impact on the infrastructure of the grid, making wires less efficient at moving electricity and pushing transformers and thermal power plants to their temperature limits. As the temperature rises, those air conditioners have to work harder to cool the air — which means they draw more power, straining the grid even more. “So you get this feedback loop,” said Fournier.