Eclipse will darken solar panels and cut off power supplies to the grid

The US will lose more than 30 gigawatts of solar energy during Monday’s total eclipse — roughly the output of 30 nuclear reactors — as sunlight is blocked during prime generating hours.

The Texas power grid will be affected the most, losing about 17 gigawatts, according to estimates compiled by the Schneider Capital Group LLC. To the northeast, the grid operated by PJM Interconnection LLC will lose about 4.8 gigawatts of utility-scale solar power and about the same amount from rooftop systems. The impact on the Midcontinent Independent System Operator grid, covering much of the Midwest, will be slightly less — 4 gigawatts.

The eclipse will briefly darken a long swath of North America, from northern Mexico to New England and the Canadian Maritime provinces. But power prices will be largely unaffected, said Timm Schneider, chief executive officer of the consulting company. Utilities have had plenty of time to ramp up alternative energy sources. “The eclipse has been pretty well-telegraphed, so utilities should be ready,” Schneider said.