During the solar eclipse that will take place on April 8, Americans will look up to the sky in eclipse glasses. But this means more than just the opportunity to worry about possible damage to your eyesight.
In an increasingly solar-powered energy ecosystem, darkening the sky at noon is a big deal. “The implications for solar power generation are actually pretty significant,” Barry Mather, a senior engineer at the National Renewable Energy Laboratory, told CNET.
Fortunately, because solar eclipses are unusually predictable, grid operators have had plenty of time to prepare for the effects. Therefore, it is unlikely that most Americans will see any changes to their electricity system.
What a four-minute eclipse means for our power grid.
Does a solar eclipse affect solar panels?
A solar eclipse, which causes a temporary loss of sunlight as it blocks the moon’s rays, is critical to the ever-growing supply of installed solar power in the United States.
“The grid will have to figure out how to match supply and demand in that window if that power source goes out, even for a few minutes,” said Benjamin Lee, a professor of electrical and systems engineering at the University of Pennsylvania.
That may seem like a blip — the total loss of sunlight will last just 4 minutes anywhere — but it ignores the eclipse’s broader effects.
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Areas within the “zone of totality” will experience total darkness, but areas near and far from that zone will still experience a partial loss of sunlight. What’s more, although totality lasts only 4 minutes, the transition in and out of the eclipse can last several hours in some places. This means a longer period of reduction in solar production.
“It’s really going to affect the entire United States to varying degrees,” Mather said.
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The effects could be particularly severe in Texas, which has increased its reliance on solar power in recent years and is directly in the path of totality, according to Jin Tan, NREL’s chief engineer.
Will the solar eclipse affect the power grid?
The nationwide loss of sunlight during the eclipse will lead to reduced solar production. But this isn’t just a problem with rooftop solar for individual homeowners, it’s also a big hit to the power grid.
That’s because utilities have invested in many large-scale solar projects, which they now rely on to keep the grid running. Each utility prepares for the eclipse in a unique way, Tan said, but generally they will need to ramp up other power sources (such as oil, gas and hydro plants) to cover the temporary loss of solar power.
That could be difficult because of the speed of the eclipse, Tan said. The diurnal transition to nighttime, which obviously reduces solar energy, is quite slow. But during an eclipse, the switching speed can be almost twice as fast, meaning utilities have to step up other power sources very quickly.
The good news is that it’s all predictable, and utilities have been here before, most recently in 2017. The NREL report notes that, “The 2017 total solar eclipse came and went without causing any disruption to North American electricity. system.” There’s more utility-scale solar than there was in 2017, but if all goes according to plan, electricity consumers shouldn’t experience any kind of gridlock.
And here’s another silver lining: “It’s like an experiment for things that are less predictable and will happen in the future,” Mather said, like storms or wildfire smoke that damage solar generation without warning.
How to watch a solar eclipse
If you want to get out there and see this heavenly sight, here are some tips: