ERCOT hits another all-time high for Texas power demand Sunday as heat wave sets new records

Leaders of the Electric Reliability Council of Texas (ERCOT), which operates the grid for more than 26 million customers representing about 90 percent of the state’s power load, repeatedly have said the agency has enough resources available to meet demand. 

But the agency late Sunday announced it was “asking Texans and Texas businesses to voluntarily conserve electricity” amid another record heat wave this summer. Such alerts are issued when ERCOT expects power reserves to fall below 2300 megawatts for 30 minutes or more, the agency said.

The grid could have considerably less flexibility than that: ERCOT’s alert projected roughly 80,200 megawatts of power generation would be available during Monday’s “tightest hour.” The agency forecasts the grid’s power needs will exceed that by about 100 megawatts around 5 p.m. 

One megawatt is enough electricity to power about 200 homes on a hot summer day.

The agency’s announcement came after a Sunday that broke records for heat and, nearly, for electricity use.

Houston reached 105 degrees at Bush Intercontinental Airport Sunday afternoon, shattering the 1909 record for July 10 of 101 degrees. Three other National Weather Service sites in the Houston region also recorded new record temperatures Sunday.  

And Texans’ peak electricity usage momentarily topped 77,400 megawatts, with the state nearly eclipsing Saturday’s hourly average record for weekend usage. Monday’s peak hourly average, meanwhile, was expected — even before ERCOT late-night alert — to set a new record for power usage. 

Record-setting temperatures, along with population growth, are helping to drive repeated electricity demand records this summer, including at least four in June and at least two so far this month. 

As recently as May, ERCOT predicted that demand this summer would peak in mid-August at about 77,300 megawatts. But peak demand already has outstripped that projection on both weekdays and weekends, driven in part by record heat that began in May and has not abated as of early July. 

Editor’s note: A prior version of this post said Sunday’s power demand topped Saturday’s record. While Sunday’s maximum power usage exceeded Saturday’s average hourly record momentarily, it did not do so for an hour.