Even though pre-announced rolling blackouts due to overloads of the electrical grid were not as severe or prolonged as they sounded like they would be last month, PG&E did have to cut off power for some communities due to what they now say was an internal communications error.
On August 15, one day after PG&E instituted the first rolling blackouts in California since 2001 in order to reduce strain on the grid during a heatwave, a message was sent in error to a large power plant in Fresno to reduce its output by about 255 megawatts of power. As the Chronicle explains following a statement by PG&E on Monday revealing the incident, the message had been intended for a smaller plant telling them to wind up to full capacity, but instead it was directed to the natural gas-powered Panoche Energy Center, leading them to wind down instead for about a half hour that Saturday evening.
The reduction in power was soon corrected, but it happened at a moment when the state couldn't afford to lose any energy capacity, and as PG&E was instituting a second day of blackouts that cut power to parts of the Central Coast. As KPIX reports, the state was in a Stage 3 energy alert, and while the Bay Area was spared power outages that day, parts of Monterey, Santa Cruz, and San Joaquin counties briefly lost power amid a major heatwave.
"During the extraordinary August 15 statewide energy capacity event, PG&E, in response to the California Independent System Operator’s call to bring certain units to full energy output, issued a verbal dispatch order in error to the Panoche Energy Center," PG&E said in a statement. "The order resulted in the temporary ramping down of Panoche’s energy output by approximately 255MW for a period of less than a half hour."
The utility says it has been "open and transparent" about the incident with the California Independent System Operator (CAISO), which had ordered all plants to wind up to full capacity on August 15. "When the error was identified, we corrected it immediately and ordered the plant to return to full generating capacity, where it stayed for the remainder of the day," PG&E says.
Monday's announcement came at the same time as reassurances from PG&E that upcoming Public Safety Power Shutoffs (PSPS) in fire-prone areas will be briefer and more targeted, hopefully leading to less hardship for customers during a deadly pandemic and ongoing unhealthy air quality.
The mistake does not seem to have been entirely responsible for the need to suddenly institute rolling blackouts for the first time in 19 years, but it was one piece of the puzzle that hot weekend in August. Warnings about rolling blackouts returned for much of the Bay Area the following week, though they never ended up being necessary.
As the Chronicle noted last month, regulators say PG&E needs to rethink how it manages power reserves from wind, solar and other sources, and how it is relying on out-of-state energy sources in times of grid strain like the August incident. During that mid-August heatwave, high temperatures were being felt in a broad swath of the western U.S., leading to power shortages in other states as well — and leading to there not being enough to go around when California came calling.
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