Texas power grid to be impacted by Oct. 14 solar eclipse

ERCOT has already been put to the test this summer, setting an all-time peak demand record of 85,464 MW on Aug. 10—just one of 10 new all-time peak demand records set this summer. Tight grid conditions prompted several appeals for Texans to conserve energy use, mostly between the hours of 3 p.m. and 9 p.m. when solar energy production dips as the sun goes down. 

On Oct. 14, daylight will begin to dim at 10:15 a.m. CT as the Moon begins to pass between Earth and the Sun, partially obscuring the view of the Sun. Maximum coverage of the Sun will occur at 11:54 a.m. CT before the partial eclipse ends at 1:33 p.m. In an emailed statement, ERCOT officials confirmed that on that day photovoltaic generation resources (PVGR), which generate solar power, are expected to experience a maximum coverage of sun ranging from 76 percent to 90 percent between 10:15 a.m. CT and 1:40 p.m. CT. Solar energy intake is expected to be hit the hardest at 11:50 a.m. CT at the height of the eclipse when the system’s “clear sky capability” will be reduced to a minimum of 13 percent. 

“ERCOT is working on forecasting models to reflect solar generation on the grid during the eclipse,” officials with the grid operator wrote in an emailed statement. “ERCOT will use all available tools to maintain grid reliability, and will continue to keep the public informed through our communications channels.” 

This summer, ERCOT has relied heavily on renewable sources of energy, like wind and solar, to meet demand. The grid operator currently has about 22 gigawatts of solar generating capacity, adding significant renewable resource capacity from 2008 to 2022. However, renewable supply is dependent on wind and sun conditions and can’t be relied on during periods of high demand. That means that Texans may be asked to conserve energy or that grid operators may have to resort to rolling blackouts if supply becomes exhausted and renewable resources are low.