Sun’s eclipse a celestial marvel, but a downer for solar power plants

Turn off the lights during next Monday morning’s solar eclipse, and while you’re at it go after the “vampires” that may be sucking $100 worth of electricity a year from your home.

That’s the advice from state utility regulators regarding the astronomical event that will darken skies across a broad swath of the United States as the moon passes between sun and Earth, disturbing animals, drawing crowds to the darkest areas where the eclipse will be total and temporarily curbing output from solar power facilities.

To offset the loss, the California Public Utilities Commission is urging people, businesses and institutions to “Do Your Thing for the Sun,” such as douse the lights, avoid charging electronic devices and turning down the air conditioning 2 to 5 degrees Monday morning.

The agency also recommends slaying “vampires,” referring to common items like coffee makers, televisions, computers and other electronics that use power when off or in standby mode and can only be truly off when unplugged.

Nearly one-fourth of the electricity used to power home electronics is consumed while the devices are turned off, and the average American household spends $100 a year on these devices, the PUC said.

In the greater Bay Area, the sun will be 76 percent obscured, compared with 85 percent in far northern California and 62 percent coverage in the Southland, farther from the 70-mile-wide band of total eclipse arcing from Oregon to South Carolina.

California public utilities, which generate nearly 10,000 megawatts of power from photovoltaic installations, will see solar power production drop by about 5,600 megawatts at the peak of the partial eclipse, which will occur from about 9 a.m. to noon Monday.

PG&E, which draws about 12 percent of its electricity from the sun, will sustain a peak loss of 2,600 megawatts, said Lynsey Paulo, a utility spokeswoman. The typical PG&E system load for a late morning on Aug. 21 is 13,500 megawatts.

“It’s an unusual and rare event,” Paulo said, describing it as the first total solar eclipse visible in the nation since 1979 and the last until 2024.

But the state’s power companies, the Independent System Operator which manages the statewide power grid, and the Public Utilities Commission knew it was coming and made preparations, she said.

When solar power dwindles Monday morning, PG&E will coordinate with the ISO to step up supplies from other sources, such as hydropower, wind, geothermal and natural gas.

As much as an eclipse is a marvel to behold, Paulo said it is not exactly novel. “We deal with an eclipse every night when the sun goes down,” she said.

Sonoma Clean Power, the public agency that supplies power to 600,000 Sonoma and Mendocino County customers, is urging people to go out Monday morning and enjoy the eclipse with special viewing glasses.

“But first, turn off your lights, your computer and anything else to help us avoid turning on those old, dirty gas-fired power plants,” CEO Geof Syphers said.

Michael Picker, the PUC president, acknowledged the eclipse is unlikely to impose any hardships. There are natural gas turbine-powered “peaker plants” around the state that can boost output immediately when needed, he said.

But the utilities agency is using the occasion to promote consumer practices -- such as using dishwashers, washing machines and air conditioners after 9 p.m. -- that will lower peak power demand.

Installing LED light bulbs, which use 75 percent less energy and last 25 times longer, also helps. If every Californian went to LED bulbs, the state could cut greenhouse gas emissions equal to the output from a coal-fired power plant in one year, the PUC said.

Picker said the PUC is pushing the concept of “negawatts,” refraining from using electricity when demand is highest.

You can reach Staff Writer Guy Kovner at 707-521-5457 or guy.kovner@pressdemocrat.com. On Twitter @guykovner.