When the total solar eclipse hits on Aug. 21, it’s going to be quite the party. The problem? Solar panels need the sun.
With the sun blocked, solar energy sources will be affected. More than 100 million solar panels are expected to be darkened, which will drop output by 20 percent — or the equivalent of all the energy the city of San Francisco uses in a week.
Previous eclipses like the one that blotted out Europe in 2015 can give us a heads up on how much solar power will plummet. In Germany, output dropped from 14 gigawatts (GW) to 7 gigawatts, according to Gizmodo. Here in the states, solar production is about 45 GW. It helps that the eclipse won’t totally black out the sun over California and other states where the most solar energy is generated, so it won’t debilitate the power grid or anything. But it’ll still mess things up.
More than 1 percent of all energy used in the U.S. comes from solar, so we rely on it, even if just a bit. A North American Electric Reliability Corporation (NERC) white paper found that the eclipse is unlikely to cause any real issues with the power system. More likely it will show us how to prepare and plan for limited resources, now and in the future. It’s really California (and North Carolina to some extent) that will be the most impacted since its the highest solar energy producer in the country.
The California Independent System Operator (CAISO), which supplies energy for the state electrical grid, estimates that the eclipse will push the grid to find 6,000 megawatts (MW) from alternative sources — keep in mind one MW powers about 1,000 homes.
But along with state energy agencies and utilities, the ISO has been prepping for the eclipse and the loss of solar power for more than a year. In a release about the solar event, CAISO wrote, “While the ISO has enough energy supply to make up for lost solar production during the eclipse, consumers should always use energy wisely.”
That’s where programmable thermostats like Nest are gearing up to help take on the energy loss. In an effort to keep our power grid from resorting to “dirty” energy from coal, nuclear, gas and fossil fuels, the Google-owned company is asking its customers to cut back on its energy usage for the eclipse.
Project Eclipse will offer an opt-in campaign. Ben Bixby, head of energy partnerships at Nest, is realistic about the relatively small loss of solar energy from the eclipse. “There’s no real danger of apocalypse,” he said in a phone call.
Even if it’s only 900 MW of lost solar energy from the eclipse, Bixby anticipates Nest users’ reduced energy use will “make a meaningful difference on the grid on this particular day.”
For eclipse day, Nest users can voluntarily join the energy-saving effort, similar to the company’s ongoing Rush Hour Rewards program that launched in 2013 that pays customers for cutting back on energy at peak times. On the device, an eclipse image will appear and ask if users want to participate in the special solar eclipse rush hour. Energy savers won’t be paid this time, however.
The entire California Public Utilities Commission is collecting pledges from residents to “do your thing for the sun.” That means finding ways to reduce electricity usage the day of the eclipse. The state utility, like Nest, wants to burn fewer fossil fuels while the state’s solar energy production dips.
Some suggestions include replacing lightbulbs with LEDs, turning off lights, unplugging electronics and appliances, and turning up the thermostat 2 to 5 degrees. Easy stuff, but not always obvious.
A state resolution calls for lower energy use during the eclipse — especially during the West Coast portion starting around 9 a.m. PT.
The last eclipse to cross the entire U.S. was in 1918, so our energy demands and technology look a bit different these days. We don’t have a lot of experience with the sun out of commission for a few hours in the middle of the day with our current power grids and supply systems. Phil Mihlmester, an energy expert and executive vice president of the global energy consulting group ICF, called the upcoming eclipse “a test case” to see how power suppliers handle the change in resources.
Based on a model looking at the electrical grid, ICF found the solar energy reduction might also be costly, especially in solar-heavy states like California.
The ICF analysis found the average energy price for ratepayers just on eclipse day might go up 7 percent in the Golden State. At the eclipse’s peak, that cost could go up as much as 18 percent. The average homeowner won’t notice the small blip in cost for one day, but the energy industry will.
“It’s not so much the total loss and needing to make up for lost solar power,” Mihlmester explained. It’s more ramping up gas energy supplies to compensate for solar energy going down. In California alone gas turbines will need to be fired up to release up to 30 MW per minute to make up the difference.
So unplugging everything could really do something to offset that gas need. “It’s always helpful,” Mihlmester said. “Energy efficiency and steps taken by consumers clearly have an effect.”
With all this energy saving and practice, we should be more than set for the next eclipse in 2024.