The Solar Eclipse and Our Electricity Supply: Why We’ve Got This Covered
The Great American Eclipse, as many are calling it, is a big deal for both committed and casual star watchers alike. On Aug. 21, starting at approximately 9:15 a.m. PT, the moon will move in front of the sun to completely block its rays, leaving a swath of people across the U.S. in eerie and fantastic darkness for about two minutes. Totality!
A total solar eclipse happens about every 18 months, but most of the time the moon’s shadow appears in remote places where very few are around to witness the spectacle. The coming August eclipse will be the first in the nation’s history to completely occur over the continental U.S.
Given that the U.S., and especially states like California, are using more and more solar power to meet electricity needs, the prospect of a temporary moon shadow has caught the attention of electricity grid operators as well.
California currently receives more than eight percent of its electricity from large-scale photovoltaic (PV) and solar thermal plants. The state also has more than 5 GW of small-scale PV (rooftop solar) installed—meeting approximately two percent of electricity demand—and that number is growing rapidly. So, it’s not surprising that the California Independent System Operator (CAISO) is looking into the effects the eclipse will have on generation that day.
CAISO expects generation from large-scale solar plants to start dropping around 9 a.m. and be reduced by about 64 percent at the height of the eclipse (assuming it’s a clear morning and potential solar generation is not already reduced by…
