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Why issue a Flex Alert if available power supply is higher than the forecasted demand?

Higher temperatures are leading to stress being put on the power grid
Higher temperatures are leading to stress being put on the power grid 02:33

SACRAMENTO -- A Flex Alert is in effect on Aug. 17 from 4 p.m. to 9 p.m. to relieve pressure on California's power grid. Still, the energy available exceeds the forecasted demand, so why issue the alert?

Multiple factors inform the decision to issue a Flex Alert, a voluntary call for Californians to reduce energy use between the given hours. Experts say the Flex Alert issued is typical for this time of the year heading into late September.

A decade ago, the alert would've been for the middle of the afternoon, but California's use of solar and wind energy has given more power stability in the hottest hours of the day.

The Flex Alert is issued with later timing now because that's when solar production goes offline and temperatures remain high.

CBS13 asked the California Independent System Operator spokesperson why a Flex Alert was issued when the forecasted demand for power was lower than the amount of power available at any given time on Wednesday by at least 15,000 Megawatts.

"So the current supply is good because we have so much solar in our resource mix, which produces at a high level in the middle of the day." Cal ISO spokesperson Anne Gonzales said in an email to CBS13.

When demand in California is driven by air conditioner usage, it tends to be highest when it's hottest outside, in the middle of the day.

Now, with more homes utilizing solar power, the demand does not look the same, or at least, energy is not used by what it was 10-15 years ago, according to Andrew Campbell, the Executive Director of the Energy Institute at UC Berkeley.

"I think the fact that the grid operator issued this warning, they see something in the data or at least in the uncertainty that calls for at least being cautious today, asking for people to make voluntary changes," said Campbell.

CBS13 asked Campbell if the state's power grid was still fragile two years after rolling blackouts hit parts of the state in 2020.

"The nature of any power grid, it has to be balanced from second to second over a very big area for it to work. Supply and demand has to always match identically; in some ways it's always fragile," said Campbell. 

More Cal ISO resources are available on the System Conditions Bulletin

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