Facing the threat of more power outages on the sixth day of a scorching heat wave, the California ISO on Aug. 19 called for residents and businesses to again power down for a significant part of the day.
California's primary wholesale grid manager issued another statewide "flex alert" calling for voluntary electricity conservation from 2 p.m. to 9 p.m. PT, urging people to raise air-conditioning thermostat temperatures, delay using major appliances, turn off lights and take other measures to ease pressure on the grid.
"Today, we believe, will be another challenging day, but we're up to the task," Gov. Gavin Newsom said during an Aug. 19 media briefing.
More power outages, such as those that hit the state on Aug. 14-15, can be avoided with conservation efforts, according to CAISO's chief.
"We do expect to meet our obligations today with the conservation measures," Steve Berberich, California ISO's CEO, said during a separate media briefing. The grid operator is seeking 2,000 MW to 3,000 MW of demand reduction, the CEO added.
Conservation works
On Aug. 18, dramatic conservation measures by residences and businesses kept demand well below projected levels. CAISO's day-ahead forecast had predicted a peak of 50,485 MW between 5 p.m. and 6 p.m. The actual peak demand was roughly 47,000 MW. That difference prevented near-certain blackouts, according to CAISO.
Consumers' power use reductions "in the most critical time of the afternoon and early evening, when temperatures remain high and solar production drops" prevented further outages on both on Aug. 17 and Aug. 18, the ISO noted in a statement.
Peak demand on Aug. 19 is forecast at 48,048 MW, compared with 53,377 MW of capacity, a number that Berberich said had grown with the availability of additional imports of electricity.
Both Newsom and Berberich said they expected demand for power to decline in coming days as temperatures moderate.
In May, a CAISO report predicted the grid operator would have sufficient power supplies this summer. At Newsom's request, the ISO is working with California energy regulators on an analysis detailing why rolling blackouts occurred at the onset of the heat wave.
More than 300 wildfires that broke out during lightning storms the last few days are not currently threatening the power system, according to Berberich.
"At least we don't have that to deal with," he said.