This story has been updated.
Thanks to statewide conservation efforts, Texas was able to avoid rotating outages Thursday, when energy demands were projected to exceed supply.
After hours of waiting to see if the Texas Electric Reliability Council of Texas would call for local brownouts, ERCOT said in an 8:35 p.m. social media post that its energy conservation request, first issued at noon, would end at 10 p.m. statewide.
ERCOT’s voluntary conservation notice was its third issued in seven days, and its fourth this summer.
The grid operator’s projections spurred San Antonio officials into action; around 2:35 p.m., city staff canceled an ongoing city budget work session to pull together an emergency press conference asking residents and local partners to immediately conserve energy and to prepare for probable outages.
“There is a very strong probability of power outages throughout the state, including San Antonio, this afternoon and this evening,” Mayor Ron Nirenberg said during the press briefing. “The city of San Antonio is working with CPS Energy, Bexar County and SAWS to conserve power locally, but we need the community’s help to conserve power, to be safe and to be prepared.”
Once the threat had passed Thursday night, ERCOT thanked Texas residents and businesses for their conservation efforts, saying that its “additional reliability tools helped us to get through a tight peak time.”
ERCOT officials declined to answer follow-up questions.
During the briefing, Nirenberg pointed blame at ERCOT for the tight grid conditions, and said the possibility of rolling outages was not a result of generation issues within the city’s municipally owned utility. CPS Energy President and CEO Rudy Garza agreed, correctly predicting it was possible that there wouldn’t be a need for outages in the San Antonio area Thursday.
“We’ve got more generation than we need today to serve the City of San Antonio and our customers here in our community,” Garza said. “So I feel good about where we are today, but we’ve got to plan for the future — and the rest of the state has got to do the same.”
Protecting the grid
While ERCOT noted it was not experiencing emergency conditions when issuing its conservation plea, forecasts were “showing a high potential to enter emergency operations this evening” due to high demand.
While ERCOT stated low wind generation was partially to blame for Thursday’s scare, its data showed lower-than-usual thermal generation — like traditional coal and natural gas plants — was also partially to blame.
When only wind generation or thermal generation is down in Texas, the grid is still able to handle demand pretty well, said Michael Webber, professor of energy resources at the University of Texas at Austin — but not when both are struggling.
“We had thermal power plants offline with outages and low winds today, and those are Texas’ workhorses,” Webber said. “If one of those is not good we are OK, but if both are offline we have real problems.”
While ERCOT has made strides to expand its capacity since February 2021’s Winter Storm Uri, adding 5 gigawatts of solar and 5 gigawatts of wind capacity in the past year, Webber explained that demand is also growing exponentially.
“Solar and wind are what have gotten us through the summer thus far,” he said. “But when demand has increased 6 gigawatts in a year — that’s a staggering number.”
Webber said he’d love to see the state utilize tools like a statewide demand response program — similar to the one CPS Energy has in place — and also more battery storage for Texas in the near future.
Should ERCOT-controlled outages occur this summer, they will likely be in 10-15 minute intervals as CPS Energy shuts off specific circuits throughout the city on a rotating basis in order for the agency to meet statewide demand, Garza said Thursday.
Since Winter Storm Uri, those citywide circuits and rotations have been fine-tuned to ensure that critical infrastructure like hospitals and public safety facilities aren’t affected, Garza said.
The utility also maintains a list of about 3,500 homes in which residents rely on life-sustaining equipment and are exempt from controlled outages.
Heat, schools and sunsets
ERCOT’s conservation request was due to extreme heat across the state, accompanied by record electricity demand as Texas continues to boom in growth. Renewables, especially solar, have helped the Texas grid stay afloat this summer by allowing the grid operator to meet increasing demand. However, solar power declines as the sun sets.
San Antonio saw a high of 100 degrees Thursday, according to the National Weather Service.
Garza said Thursday’s conditions were “the first actual test” the city and county have had had dealing with statewide grid issues since Uri.
The extreme heat, plus schools going back into session and the sun setting earlier in the day are all likely reasons for ERCOT’s latest conservation requests, Garza said.
“It really has to do with changing patterns,” he said. “We’ve got schools back in service, so the load overall across ERCOT is up, and it’s up in the evening hours. In the current kind of weather pattern, wind has started to ramp down a little earlier in the evening, at the same time that solar typically ramps down.”
San Antonio’s school districts, including the largest in the county, Northside Independent School District, were asked by CPS Thursday afternoon to curtail energy use, according to district spokesman Barry Perez.
In response, the district directed classrooms and common spaces to raise thermostats by three degrees.
The district, which began ramping up energy usage on campuses several weeks ago in anticipation of the staff return to school, generally starts its cooling systems at 6 a.m. and shuts them down one hour after the close of school for campus buildings, and at 5 p.m. for district facilities.
San Antonio Water System President and CEO Robert Puente said that SAWS didn’t anticipate rolling outages to affect its water service to customers. During Winter Storm Uri, pipes across the city froze, limiting residents’ access to water.
“State leaders will tell you that they took care of ERCOT — it’s evident that they did not,” Puente said, pointing to the supply and demand graph posted on a projector behind him. “They’d rather pick on our city council and our mayor, telling them what to do, than to fix ERCOT.”
SAWS’ most critical pump stations have since been added to CPS Energy’s list of critical infrastructure to ensure they receive power, said SAWS spokesman Gavino Ramos.
Late last year, SAWS and CPS Energy announced they were going to fortify SAWS’ system against major power outages by connecting the city’s critical pump stations to backup generators. Ramos told the San Antonio Report that work is not yet completed but it is underway.
New ERCOT notifications
The voluntary conservation notice is part of ERCOT’s new Texas Advisory and Notification System, launched in May. The system alerts the public of grid conditions and issues weather watches as necessary to notify Texans when conditions may become strained. The new communication system was launched as a part of the grid operator’s improvements in response to Uri, which saw statewide rolling blackouts during days of sub-freezing temperatures.
ERCOT set yet another new unofficial peak demand record of 85,435 megawatts on Aug. 10 — the 10th record it has set this summer. Last summer, ERCOT set 11 peak demand records with a high of 80,148 megawatts. One megawatt is enough to power 200 Texas homes on a hot day.
Earlier this summer, Pablo Vegas, ERCOT’s president and CEO, told San Antonio reporters it’s “very possible” that Texas will continue to break energy demand records this summer, but said he was not particularly concerned about being able to meet that demand. ERCOT has up to 97,000 megawatts of resource capacity available for peak summer load, according to its summer 2023 Seasonal Assessment of Resource Adequacy.
ERCOT has a “weather watch” in place through Sunday.
“I think we will be in this condition of heightened awareness until the 100-degree days end,” Garza said.
San Antonio residents can see CPS Energy’s tips on how to conserve energy here.
Senior reporter Iris Dimmick and education reporter Isaac Windes contributed to this report.
CPS Energy is a financial supporter of the San Antonio Report. For a full list of business members, click here.
