Solar eclipse to affect solar power plants Aug. 21

A solar eclipse on Aug. 21 will impact electricity generation for about 1,900 utility-scale solar photovoltaic power plants in the United States, according to the U.S. Energy Information Administration. But only a small amount of solar capacity is in the path where the moon will completely obscure the sun.

“The North American Electric Reliability Corp. (NERC) does not anticipate the eclipse will create reliability issues for the bulk power system,” according to the EIA.

The path in which the moon will completely block the sun runs diagonally, from the northwest to the southeast, between Oregon and South Carolina. “Solar-powered generators centered in the path of totality will be affected the most, as the moon will block all direct sunlight for up to three minutes,” according to the EIA. “These generators will also be affected to a lesser extent throughout the entire eclipse event, which will last for up to three hours, measured from the onset to the ending of any blockage of direct sunlight.

“The path of totality only affects 17 utility scale solar PV generators, mostly in eastern Oregon,” according to the EIA. “Hundreds of plants totaling about 4 gigawatts (GW) of capacity — mostly in North Carolina and Georgia —will be at least 90% obscured.” The northern half of Arkansas will be 90% obscured while the southern part will be 80% obscured.

Across the nation, 2.2 gigawatts of solar capacity will be impacted in areas that will be 80% obscured, and 3.9 gigawatts will be affected in areas at least 70% obscured. While California isn’t in the path of totality, the eclipse will reduce the state’s solar generating capacity by nearly 4.2 gigawatts. In North Carolina, solar energy output is expected to decline to 0.2 gigawatts, from about 2.5 gigawatts.