- A total eclipse of the sun on Aug. 21 will throw shade across 1,900 solar generators in the United States, but is not expected to have a significant impact on the reliability of the bulk power system.
- Only a handful of solar capacity lies in the "zone of totality," where the eclipse will entirely block out the sun for three minutes.
- But hundreds of plants totaling about 4 GW capacity will be at least 90% obscured, EIA said. Those plants are located primarily in North Carolina.
Astronomy enthusiasts are eagerly awaiting the upcoming eclipse, but for most solar generators the event will be little more than a passing cloud.
EIA said during the eclipse, generators in the area will need to increase their output to account for diminished solar capacity. But the impact will be relatively small and brief, and the North American Electric Reliability Corporation does not foresee any serious impacts.
Another 2.2 GW and 3.9 GW of capacity is in areas that will be at least 80% and at least 70% obscured, respectively.
Solar-leader California is not in the path of totality, but the California Independent System Operator said it anticipates an almost 4.2 GW decrease in solar generation, which will run from about 9 a.m. to noon, local time.
"To ensure electricity demand is met during those hours, CAISO plans to replace solar generation with electricity from natural gas and hydropower plants, the latter of which are generating at higher levels than previous years," EIA wrote in its Aug. 7 Today in Energy note.
Only 17 utility-scale solar generators, mostly in eastern Oregon, lie in the sone of totality. Plants with capacity totaling 4 GW — mostly in North Carolina and Georgia — will be at least 90% obscured.