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Strain on California power grid likely to prompt rolling blackouts during extreme heat wave

Matthias Gafni, San Francisco Chronicle  


    Sep. 5—The forecasted energy load on California's electrical infrastructure exceeds what state officials expect to have at their disposal on Labor Day, prompting calls for conservation and concerns that power may need to be cut to some homes Monday night amid soaring temperatures.

    State officials anticipate needing 48,817 megawatts of electricity Monday, which would leave the state with a 2,000 to 4,000 megawatt deficit, California Independent System Operator President and CEO Elliot Mainzer said. He said the projected shortfall has created "the highest likelihood of rotating outages we have seen so far this summer."

    "Because of the increasingly extreme conditions, we will need significant additional consumer demand reductions during the hours of 4 p.m. to 10 p.m. on Monday and access to all the emergency tools that the state and utilities have established for an extreme event like this one," Mainzer said in a statement. "We thank electricity consumers for their sustained effort to help us maintain reliability during these very difficult conditions."

    Monday's Flex Alert marks the state's sixth straight day calling for consumers to cut their electricity use. So far it's worked, as California residents have saved 600 to 700 megawatts in recent days.

    State regulators extended Monday's Flex Alert by an hour, covering 4 p.m. to 10 p.m., and asked consumers to avoid running appliances, set thermostats to 78 degrees or higher and turn off all unnecessary lights during those peak hours.

    And Tuesday has state officials even more concerned. The peak load projected for Tuesday is 50,099 megawatts, even higher than Monday's forecasted demand. The highest electrical load ever drained by Californians was 50,270 megawatts on July 24, 2006.

    This week's heat wave is expected to last through Friday with daytime temperatures forecasted to be 10-20 degrees above normal. Early Monday morning, around 3 a.m., temperatures still remained in the 80s to low 90s in some inland portions of the Bay Area. The National Weather Service extended an excessive heat warning and heat advisory through Thursday 8 p.m. Conditions are dangerous to those vulnerable to heat and without access to cooling and hydration.

    California grid operators are monitoring wildfires to make sure they don't damage generators or transmission wires. Several generators are already offline, tightening electrical supplies.

    State officials suggest consumers pre-cool their homes with air conditioning during the day, when electrical demand is not as high.

    Matthias Gafni is a San Francisco Chronicle staff writer. Email: Twitter: @mgafni


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