By Donna Beth Weilenman
Martinez News-Gazette
Special to the Herald

The solar eclipse begins locally at 9:01 a.m. Monday, and while California is south of the path of totality, prepared Benicia residents with the proper equipment can watch as the sun is masked to a sliver by the moon.
The maximum eclipse, when the moon appears as close to the center of the sun as we’ll see here, occurs at 10:15 a.m., and the global event ends in Benicia at 11:37 a.m.
During that time, the moon will cover 76.58 percent of the sun, according to Time and Date AS, a Stavanger, Norway, company that provides time, time zone and calendar services.
Californians as far south as San Diego will observe 57 percent coverage of the sun, while those in Redding, Eureka and places farther north will experience closer to 90 percent, according to eclipses2017.org, a site dedicated solely to the celestial event.
The moon’s shadow darkening the state means solar panels won’t be generating electricity.
But power customers shouldn’t worry, say those who best know the grid that supplies the state’s utility companies.
How much of the state’s power is generated by solar panels depends on the weather, the season and the time of day. On a late spring or early summer sunny day, between 30 and 40 percent of the demand is supplied by solar energy, said Deane Lyon, real time operations shift manager at the California Independent System Operator (CAISO).
CAISO handles 80 percent of the electricity grid in California, and began planning for the solar eclipse about three years ago. “We started planning in earnest the middle of last year,” Lyon said.
“We have the capacity of about 10,000 megawatts of solar connected with the grid, not counting the amount of megawatts generated by rooftop solar installation, because they are considered ‘behind the meter,’ not the solar field,” said Anne F. Gonzales, CAISO’s senior public information officer.
Lyon said rooftop solar panels generate another 5,800 megawatts of energy. Because the rooftop installations are categorized differently, CAISO doesn’t track the power they provide, although the California Energy Commission does, she said.
When the sun stops shining on those rooftop panels, “we’ll see an increase in demand” as well as a loss of those additional power resources, Lyon said. In addition, power consumption in general could go up, not just from those who have lost the electricity from their own panels.
Street lights could come on and people could turn up thermostats because temperatures will drop, he said. On the other hand, some companies could “go dark” for the time of the solar eclipse, and some people may treat Monday like a holiday.
Consumers shouldn’t waste electricity, and Benicia has several programs that encourage conservation. But Gonzales and Lyon said the eclipse won’t prompt a “flex alert.”
In fact, customers shouldn’t notice any difference at all, they said.
Flex alerts are issued when utility customers need to cut back on their consumption to prevent power use outstripping supply because of weather or if power plants or lines are affected in ways that prevent electricity deliveries. High temperature days, wildfires that damage power plants or destroy deliver lines may prompt those alerts, they said.
But Monday, CAISO will make up the solar loss in other ways.
“When the moon is passing in front of the sun, we’ll make it up with hydroelectric power. We are lucky we had a good water year,” Lyon said. In addition, thermal and gas-fire generation will cover the solar loss.
There are no oil-fired plants, and only one small coal plant in Stockton, he said. Natural gas-fired plants are fossil fuel, and the state has a number of those, as well as a couple of nuclear units in Southern California.
The state has another 5,000 megawatts of wind-generated electricity, Lyon said. In following the governor’s renewable portfolio, California is integrating more and more renewable sources of power, he said. The public can follow the renewables’ generation through CAISO’s smart phone application, ISO Today.
Individual solar panel owners can track their own solar production online, and they’ll see a percentage of their electricity generation start to decline about 9 a.m., Lyon said.
“The maximum obscuration will be about 10:22 a.m., and it will take a couple of minutes. Then the sun will come from behind the moon and start production,” he said.
Lyon and Gonzales called the eclipse an opportunity to educate the public “and remind the public the grid is here, working for them, and there are times there’s stress on the grid. And conservation is always good to relieve the stress,” Gonzales said.
Of Pacific Gas and Electric’s customers, 300,000 have rooftop solar panels, said Deanna Contreras, company spokesperson. That’s 25 percent of all rooftop solar arrays in the country.
She agreed that while solar electricity generation will decline, “you won’t see any impact to electric service.”
The last time PG&E had to plan for a solar eclipse was 1979. That year, no one had any solar panels, including the grid, Contreras said.
The utility will be doing its own part to conserve, by halting non-essential maintenance work, using the grid to distribute power and coordinating with CAISO to access power from multiple sources.
Like CAISO, PG&E has been ramping up for the eclipse for some time. Contreras said the event could cause a potential drop off of 2,600 megawatts of solar energy to the utility’s service area. While it’s not expected, PG&E is asking customers to be ready to respond, should emergency conservation measures be requested.
Contreras warned residents against looking at the sun Monday, especially since this area will experience only a partial eclipse.
“Eclipse viewers should use special-purpose solar filers, such as eclipse glasses or hand-held solar viewers purchased from authorized dealers of such products,” she said.
Those who haven’t obtained the glasses by now can still observe the moon’s shadow by making projection or pinhole viewers.
One type can be made using a shoebox. Cut a one-inch square hole in one end of the box. Cover the hole with aluminum foil and tape the foil securely to the box. Using a tack or pin, make a small hole in the foil.
At the opposite end of the box, tape white paper that will become a screen for the eclipse image. Cut a small peephole on a side wall, and seal the box with black tape to avoid light leaks. Aim the foil end toward the sun and look into the peephole to see an image of the eclipse on the inside viewing screen.
A simpler pinhole viewer can be made of two pieces of cardboard. Make a pinhole in one piece and hold that piece toward the sun. Hold the other piece away from the sun to project the image of the eclipse through the pinhole.
Live streaming of the eclipse and event-related activities are available from NASA on its web page https://eclipse2017.nasa.gov, and some television stations will be broadcasting views of the total eclipse.

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