Another freeze is expected in Houston. Will the Texas grid be fine again?
The Electric Reliability Council of Texas, the state's power grid operator, is expected to pass its second test of the winter early next week, when another arctic front is anticipated to bring frigid temperatures to much of the state.
As of Thursday morning, ERCOT’s public forecast, which only spans six days out, showed ample power supply to meet demand through the end of Wednesday, even as Texans are anticipated to use more electricity to heat their homes and businesses.
So far, weather forecasts anticipate Tuesday to be next week’s coldest day, according to Houston Chronicle newsroom meteorologist Justin Ballard. On that day, the narrowest gap between power supply and demand is expected to be approximately 12,000 megawatts around sunrise, according to ERCOT's dashboard as of Thursday. That's magnitudes above ERCOT’s 2,500-megawatt threshold for triggering a grid emergency.
“ERCOT is monitoring the cold weather approaching Texas and will keep Texans informed on grid conditions through our various communication channels. Grid conditions are expected to be normal,” ERCOT spokesperson Trudi Webster wrote in a Wednesday email.
Last week, ERCOT issued a weather watch, a notice that it would closely monitor weather conditions because there was potential for lower power reserves. Though a few inches of snow fell in the Dallas-Fort Worth area, the grid operator had plenty of electricity available to meet demand and didn’t have to initiate a grid emergency nor any outages.
ERCOT’s primary responsibility is to ensure the supply of power matches demand at all times. If demand were to come too close to supply, equipment across the grid network could be damaged, which could in a worst-case scenario lead to a total grid failure and outages for weeks or even months.
When ERCOT’s power reserves fall below 2,500 megawatts, the amount of power needed to supply approximately 625,000 Texas homes, the grid operator can initiate three levels of emergency to access various tools that increase supply or decrease demand. As a last resort to reduce power demand, ERCOT can initiate rotating outages, which are supposed to last about an hour and “rotate” between neighborhoods.
Upcoming freeze
How the grid holds up and if there are outages depends largely on the severity of the weather. Extreme cold not only prompts Texans to use more electricity, but can also limit electricity supply by freezing power plants and reducing the production of natural gas, the Texas grid's main fuel source.
“Particularly when you get a statewide average low temperature around 15 (degrees Fahrenheit), that's where you really start to reach a level where it's like, ‘Okay, there could be problems,’” said Doug Lewin, president of Stoic Energy Consulting.
Temperatures ranging in the 20s to 30s are likely to arrive in the Houston metro area beginning Sunday night, according to a Wednesday weather forecast from newsroom meteorologist Roberto Villalpando. Some ice or snow could be possible in the region from Monday to Wednesday, he said.
Matt Lanza, a popular Houston-based meteorologist and CenterPoint Energy's meteorology manager, said in a Tuesday post on X that forecast details are still uncertain, but the upcoming cold snap is “not 2021,” referencing the infamous February 2021 freeze, which killed hundreds and pushed ERCOT to order dayslong outages for millions across Texas. There's an approximately 80% chance of outages this month if Texas were to see conditions similar to the 2021 freeze, according to a November ERCOT report.
Next week’s temperatures will likely be more similar to last January, Lanza said in his X post, when the Houston area also saw frigid temperatures over the Martin Luther King Jr. holiday weekend. During last year’s MLK weekend freeze, ERCOT asked Texans to conserve electricity but ultimately didn’t initiate a grid emergency or outages.
ERCOT improvements
If ERCOT did have to initiate outages, ERCOT and grid experts have said they’d likely be much less disruptive than the outages in 2021 and last hours instead of days. That’s in part due to improvements to the grid, such as required winter-proofing of power plants and a program for power plants to maintain backup fuel in case of a natural gas shortage.
ERCOT is also in better shape because the Texas grid has added more than 44 gigawatts of power capacity since 2021, enough to power more than 11 million homes during the hottest days, according to an analysis of ERCOT data by Garrett Golding, assistant vice president for energy programs at the Federal Reserve Bank of Dallas. Nearly two-thirds of those additions have been solar arrays and battery storage, resources that “saved the Texas grid last summer,” Golding wrote in his Tuesday blog post.
The changing composition of the grid has also added new challenges. The highest-risk period for outages in the winter is around sunrise, when Texans begin getting ready for school and work but solar power capacity hasn’t fully ramped up yet. In that period, natural gas power plants and battery storage are critical in meeting demand.
‘Localized’ outages
Though 2021 has heightened scrutiny of ERCOT's operations during freezes and heat waves, ERCOT-initiated outages because of a potential imbalance of power supply and demand are rare.
The most likely outages that could occur are localized outages caused by freezing rain and snow damaging power lines and poles. Those localized outages are the responsibility of the local transmission and distribution utility, which in Houston is CenterPoint.
CenterPoint took a number of measures before winter began to prepare for possible storms, according to a company statement issued Wednesday afternoon. Those include inspecting and testing critical equipment, installing heaters and devices to prevent ice damage and buildup, repairing damaged or degraded thermal insulation materials and positioning compressed natural gas trucks to supplement the natural gas system if needed, the company said.
“Our teams are well-prepared and ready to respond to any potential impacts from the forecasted colder temperatures. We have enhanced staffing plans in place and crews stationed across the communities we serve, so that our teams can safely and quickly restore service to any impacted customers,” Darin Carroll, CenterPoint's senior vice president of electric business, said in the Wednesday statement.
Houston-area customers that do experience an outage can report that outage via CenterPoint’s updated outage tracker. The utility also rolled out a new Texas-focused X account on Monday under the handle @CenterPoint_Texas.