California’s rolling blackouts this summer were caused largely by a combination of planning failures that led to a lack of adequate power supplies, state energy leaders told Gov. Gavin Newsom on Tuesday.
A deer walks through dry grass beneath high voltage power lines seen from Terrace Drive in El Cerrito in September.
Electricity demand exceeded what the state had secured because of an extreme heat wave, fueled by climate change, that affected areas across the Western United States, three crucial energy agencies said in a report about the outages. That’s in line with what grid managers have maintained since the blackouts happened in August.
Current energy resource procedures “are not designed to fully address an extreme heat storm like the one experienced in mid-August,” said top officials at the California Independent System Operator, the California Public Utilities Commission and the California Energy Commission.
Supply goals have also failed to ensure that enough energy is available during the evening hours as the state shifts more heavily toward a cleaner power grid, the report said. Officials have stressed that the problem lies not with any inherent issue in renewable power but rather a failure to ensure enough was available when needed.
The state’s electricity market also contributed to the shortfall, including by not scheduling sufficient supplies ahead of time, according to the report.
“The combination of these factors was an extraordinary event,” the energy leaders wrote in a letter attached to the report. “But it is our responsibility and intent to plan for such events, which are becoming increasingly common in a world rapidly being impacted by climate change.”
The report is a preliminary response to two rounds of rolling blackouts imposed by the system operator on Aug. 14 and 15 because electricity supplies fell short of high demand during the widespread heat wave persisting at the time. It was the first time in nearly two decades that the state endured rotating power outages caused by a power shortage.
Grid managers have warned of more potential rolling blackouts several times afterward, but no more were actually implemented.
To assure more reliable power in 2021 and beyond, the energy agencies said the state must keep current power generation and storage projects on schedule and find a way to bring more resources into the mix by next year. They also recommended updating electric planning targets to better account for extreme weather and the state’s transitioning power mix.
Another possible explanation for the Aug. 15 blackouts emerged more recently when Pacific Gas and Electric Co. admitted that it had mistakenly told a Fresno County power plant to scale back just before that day’s outages happened. PG&E had intended to tell a smaller plant to ramp up and fixed the mistake in about 30 minutes, the company said.
Mark Rothleder, vice president of market policy and performance with the system operator, could not say with certainty how great a role the PG&E error played on Aug. 15.
PG&E said it looks forward to helping the energy organizations reduce the likelihood of future shortages.
“PG&E continues to believe the state must do more to ensure reliability of the electric grid, particularly as the energy market in California continues to evolve and as we experience more frequent and severe hot weather because of climate change,” the company said.
A more complete investigation into the rolling blackouts is expected by the end of the year.