Sep. 5—California's electrical power grid moved to its second level of emergency alert Monday evening and may also be tested like never before Tuesday, officials warned, as they urged the public to ramp up conservation efforts or face the prospects of losing power during a historic heat wave that isn't done roasting the state.
The expected energy load driven largely by air conditioning demand has intensely strained the state's power supplies, and Tuesday is anticipated to be even worse. Officials have asked residents to cut their electricity use from 4 to 9 p.m. Tuesday — the seventh straight day of such requests, known as Flex Alerts. They have also preliminarily declared the initial stage of emergency operations Tuesday, after moving through the first few stages of emergency Monday.
Electrical demand is expected to be the highest ever Tuesday, California Independent System Operator President and CEO Elliot Mainzer said Monday at a news conference.
"Right now our goal is to not see that number," he said.
To keep demand from exceeding the state's supply, Mainzer stressed that consumers would need to increase their electrical saving efforts two to three times what they did in the early days of the historic heat wave.
On Tuesday, the state is predicting a 51,000 megawatt load. Officials issued an emergency energy watch for 5 to 9 p.m., a step that encourages market providers to offer supplemental energy or savings, or both.
A PG&E spokesperson said in an email Monday evening that "the potential for rotating outages has increased significantly," but the state hasn't directed the company to cut power anywhere yet. Rotating shut-offs could occur, typically for one to two hours, in blocks, PG&E said.
A spate of small-scale power outages, including in the Napa County, Vacaville and Pleasant Hill areas, hit the region Monday. The cause for most of these was not immediately clear, though power infrastructure can fail in extreme heat, separate from rolling blackouts. An outage in Moraga, for example, was blamed on the weather.
State officials anticipated needing 48,817 megawatts of electricity Monday. Mainzer said a projected shortfall has created "the highest likelihood of rotating outages we have seen so far this summer."
So far the Flex Alerts have worked, as state residents have saved 600 to 700 megawatts in recent days. State regulators have asked consumers to avoid running appliances, set thermostats to 78 degrees or higher and turn off all unnecessary lights during those peak hours.
As resources dipped low Monday, the state moved to a Stage 2 emergency from 6:30 to 8 p.m., which allows it to dip into emergency power reserves, electricity from last-minute imports and generators. Mainzer estimated the state has about 3,000 megawatts as backup, which provides a small "buffer."
If a Stage 3 is reached and power must be cut, state regulators will ask utilities to determine the best way to drop their usage, probably rotating across systems, hopefully for short durations, Mainzer said.
The highest electrical load ever drained by Californians was 50,270 megawatts on July 24, 2006.
Fortunately, the Pacific Northwest has avoided the heat spell, which has allowed California to import some power from that region. Utilities have agreements to share power during emergencies, Mainzer said.
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.
This week's heat wave is expected to last through Friday with daytime temperatures forecaste to be 10 to 20 degrees above normal. 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 8 p.m. Thursday Conditions are dangerous to those vulnerable to heat and without access to cooling and hydration.
State officials suggest consumers precool their homes with air conditioning early in the day, when electrical demand is not as high.
Severin Borenstein, a UC Berkeley professor of energy and member of the ISO's governing board, noted on Twitter that it wouldn't take that much for the public to avert blackouts.
"Today looks tough tomorrow looks really tough," Borenstein tweeted Monday. "But reducing system demand by even 10% would virtually eliminate any concerns."
San Francisco Chronicle staff writer Mallory Moench contributed to this report.
Matthias Gafni is a San Francisco Chronicle staff writer. Email: firstname.lastname@example.org Twitter: @mgafni
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