California ISO preps solar-heavy grid for total eclipse this summer
California’s infamous duck curve will go into overdrive in August when a solar eclipse casts a shadow over the Pacific Northwest.
The partial eclipse will occur between 9:02 am and 11:54 am and will obscure the sun by 76% in Northern California and by 62% in Southern California.
The amount of solar power on California’s grid has grown so large that the eclipse will interrupt the normal morning power ramp up at the start of the eclipse and be followed by a greatly accentuated ramp up from 10:22 a.m. to noon as the moon moves past the sun.
Overall, CAISO expects to see a 4,194 MW reduction in solar generation during the 82 minute duration of the eclipse, which is a ramp down rate of 70 MW/minute. As the eclipse wanes the ramp up will be 98 MW/min. The estimated ramp rate for a clear day at that time of year would be 12.6 MW/min.
Assuming the sky is clear, CAISO expects to see a 1,365 MW increase in load as a result of obscured residential solar panels. The operator estimates there will be about 5,800 MW of rooftop solar installed by the mid-August. 35% percent of the rooftop solar is C&I installations.