A mistake by Pacific Gas & Electric led to rolling blackouts during California’s extreme heatwave last month. According to the utility, it sent the wrong message to the wrong power plant. On August 15, just before 6:15 p.m., PG&E accidentally told a 400-megawatt gas-powered electricity plant to reduce its power output, instead of directing a different power plant to increase its power output to relieve the immense strain on the grid due to an extreme heatwave. PG&E told the San Francisco Chronicle the mistake amounted to just “roughly 0.5%” of the nearly 45 gigawatts of demand on the grid at the time. That 0.5%, however, created a shortfall sufficient to cause rolling blackouts for as many as 2 million Californians.
Extreme heat and heatwaves are some of the clearest impacts of climate change on extreme weather and kill as many as 5,600 people living in the U.S. every year. Extreme heat heightens societal inequities — extreme heat danger is often worst in historically redlined neighborhoods. The PG&E admission that its mistake led to the August blackouts is consistent with grid operators’ statements that California’s commitment to clean energy did not cause the rolling blackouts. (San Francisco Chronicle, SFist, KPIX, Climate Signals background: Extreme heat and heatwaves, August 2020 California heatwaves)