A CPS energy power line runs through a ranch in rural Bexar County.
A CPS Energy power line. Credit: Bonnie Arbittier / San Antonio Report

For the first time in more than five years, Texas’ electrical grid operator is calling for people to conserve electricity to help avoid rotating power outages around the state.

The Electric Reliability Council of Texas, or ERCOT, on Tuesday issued a level 1 “energy emergency alert.” That signaled that the gap between electricity demand and supply from the state’s power plants, wind farms, and solar arrays had narrowed to within 2,300 megawatts and was not expected to recover for at least a half-hour.

Between 3 p.m. and 7 p.m. ERCOT officials asked people to set thermostats 2 to 3 degrees higher than normal, unplug unused appliances, avoid using heavy-duty appliances like washers and dryers, and to turn off pool pumps for a few hours.

The alert also allows ERCOT to tap all available power supplies, including other power grids to which ERCOT connects.

ERCOT has not issued such a warning since January 2014, spokesperson Leslie Sopko said. If margins get tighter, ERCOT can call on large industrial customers that have agreed to drop their use during emergencies. Rotating blackouts would not start until the reserve drops to 1,000 megawatts.

The tight margin between supply and demand is no surprise to Texas grid watchers. Since at least March, ERCOT officials have been saying that reserves would be tighter this summer than they had been in years.That’s due to industrial growth, a population boom, and the closure of at least four Texas coal-fired power plants in 2018.

Vistra Energy subsidiary Luminant, a private energy company, shuttered three of its plants. CPS Energy also ceased running its Deely coal plant at the end of the year.

“ERCOT is prepared to use the tools and procedures that are in place to maintain system reliability during tight conditions,” ERCOT President and CEO Bill Magness said in a May statement, when the grid operator was predicting the reserve margin would drop to 8.6 percent.

From 2020 through 2023, ERCOT is predicting that reserve margin will raise again, primarily due to wind and solar projects in the queue to be connected to the grid. 

ERCOT’s announcement came a day after electricity demand in the San Antonio area soared to an all-time record, according to CPS Energy officials.

The municipally owned electric and gas utility on Tuesday announced a peak demand record of 5,109 megawatts set between 4 and 5 p.m. Monday, up from the previous record of 5,080 megawatts set on July 23, 2018.

“With temperatures expected to soar this week and into next, customers are encouraged to take key actions to reduce their use throughout the hottest part of the day, between 3 [and] 7 p.m.,”utility officials said in a news release. “Typically, a spike in electric consumption is seen during this time of day when area temperatures reach their highest and most people are returning home from work.” 

Temperatures in San Antonio reached a high of 101 degrees Fahrenheit on Monday, according to National Weather Service data. Forecasters are predicting continued extreme heat on Tuesday, with a high of 102 degrees. 

Electricity demand on the statewide power grid also reached a record high on Monday, according to ERCOT. Demand soared to 74,531 megawatts between 4 and 5 p.m.

Demand on the Texas grid has been setting records this summer since at least Aug. 7, according to ERCOT. 

For context, 1 megawatt can power approximately 200 homes for about an hour “during the hottest part of a Texas summer day,” according to CPS Energy officials. 

Thanks to the utility’s demand-response programs, smart thermostats, and other conservation measures, CPS Energy customers were able to shave off a little more than 184 megawatts during the peak demand period, corporate communications director Melissa Sorola said in a text message. That’s enough to power 37,480 homes, she said.

Brendan Gibbons is a former senior reporter at the San Antonio Report. He is an environmental journalist for Oil & Gas Watch.