In the three years since deadly blackouts paralyzed Texas, two major winter storms have hit the electricity grid without plunging the state into blackouts.
Texas has touted its success during those two events — Elliott in December 2022 and Heather this January — as proof that grid changes passed after 2021’s Winter Storm Uri are working. More oversight of how power plants prepare for cold snaps, plus a more diverse grid, have contributed to survival in extreme winter weather.
But is that enough — especially if the grid teeters during an even worse storm?
The lessons from Texas carry implications far beyond the Lone Star State and its mostly isolated grid. Officials in other regions are watching how Texas fortifies its grid against extreme conditions in both winter and summer and how the state’s policies after the deadly effects of Uri can protect customers in sub-freezing temperatures.
More than 240 people died in Texas because of Uri and the associated grid crisis, which left over 4 million homes and businesses without power. As demand skyrocketed from people heating homes and some power generators buckled due to weather, parts of the grid were taken offline to prevent a total collapse of the power system.
“We already know people have died from controlled, rolling outages,” said Michael Jacobs, a senior energy analyst at the Union of Concerned Scientists. “In an uncontrolled, indeterminate length blackout, the potential is there for a death toll many times larger than what we saw in 2021.”
A report released in December 2023 found that the main Texas grid is overly reliant on natural gas generators to restart the grid after a blackout that interrupts all power on the grid. Authors from the Federal Energy Regulatory Commission and the North American Electric Reliability Corp. (NERC) as well as six regional entities wrote that the Electric Reliability Council of Texas (ERCOT) could do more to diversify the mix of resources that would help jump-start the grid.
A big worry: Natural gas plants had significant problems during Uri and could face similar challenges in a future winter storm. A report from the University of Texas found that at least five black-start plants reported issues with fuel supply during Uri.
A potential power failure described in the FERC/NERC report would be more widespread — and costlier, Jacobs said.
Texas officials have worked to shore up the grid by promoting more natural gas construction, even as the grid shifts to emphasize renewables, raising questions about how the grid might fare in future winter storms.
Here are four questions answered about Texas’ electricity system.
What’s different from 2021?
In short: plenty.
“The ERCOT grid performed reliably during Winter Storm Heather due to a combination of grid reliability tools, successful generation fleet, and conservation efforts by Texas residents and businesses,” ERCOT said in a statement to E&E News.
Texas officials had conducted nearly 1,800 weatherization inspections between 2021 and the end of 2023, ERCOT CEO Pablo Vegas said in a press conference before the January cold snap.
That appears to have translated into better performance in January. At most, about 7,000 megawatts of coal and gas plants were offline on the morning of Jan. 15. That’s about half the peak of outages in 2022 during Elliott.
One megawatt can power about 200 homes during peak times in the ERCOT region, according to the grid operator.
That meant the lights stayed on even as energy demand set three unofficial winter records, topping out at more than 78,000 MW, as major cities in Texas saw temperatures in the mid-20s and teens. That’s only about 9 percent lower than the all-time ERCOT demand record set in August 2023.
In a presentation to the state Public Utility Commission last week, ERCOT Chief Operating Officer Woody Rickerson said thermal power plants — those that run on coal, gas or nuclear power — supplied most of the energy during the three peaks in demand. That, he added, is a “testament to how well and needed those thermal plants are.”
Michele Richmond, executive director of Texas Competitive Power Advocates, said in an email that the thermal fleet “performed exceptionally well throughout the cold, which was longer in duration than Winter Storm Elliott.”
While certain operational issues are to be expected during extreme weather events, the thermal/dispatchable fleet has seen improved performance year over year,” said Richmond, whose group represents Texas power generators. “This is due in no small part to the measures that have been implemented post Uri, such as enhanced weatherization and secondary fuel sources.”
Renewable energy also played a crucial role, with solar power setting a generation record during one afternoon of the recent winter storm, accounting for about 20 percent of all power at that time. Wind power also kept up during the cold weather, contributing as much as 30 percent of power at some times.
Still, both Elliott and Heather were far less intense than Uri — meaning it’s hard to know how weatherization reforms would fortify the power sector for a storm with more extreme temperatures, ice and snow.
“We want to be careful to not read too much into this,” said Doug Lewin, the president of Stoic Energy Consulting and a Texas grid expert who supports the use of renewables and energy efficiency efforts. “That being said, even compared to Elliott, there were some very encouraging things.”
Can the grid keep up with demand?
Data suggests that Texas can produce enough electricity to keep the lights on — if ERCOT forecasts are correct and weather isn’t too extreme.
Record-setting demand during Heather came after warnings last fall that the grid faced a roughly 20 percent chance of a winter grid emergency — which could include rolling blackouts — under frigid conditions. In fact, ERCOT requested that power providers bring some retired plants back online as an emergency reserve, although it abandoned that plan due to a lack of interest.
ERCOT’s region also smashed summer demand records during heat waves, with 10 all-time demand records being set in 2023 alone. A growing population, more electrification of homes and industrial demand have all pushed up demand.
It’s possible that demand was higher during Uri, but ERCOT did not have enough generation to meet it. Independent estimates by Texas A&M University pegged demand at 82,000 MW, although ERCOT has said its own estimates are lower.
The skyrocketing demand figures have led to concerns from regulators about demand outstripping supply, especially at times when solar or wind power is diminished by weather. State lawmakers passed a plan last year to incentivize more natural gas plants to come onto the grid, with a new market design and a set of state-backed low-interest loans for builders of new gas plants, which was approved by voters in the fall.
“As electricity demand continues to grow, we look forward to working with the Public Utility Commission of Texas as they seek to balance the need for more dispatchable generation with growing intermittent resources, and battery storage,” said Todd Staples, president of the Texas Oil & Gas Association, in a statement a day after the storm ended. “Continual refinement of the needed generation mix and forecasting tools will assist in meeting Texas’ future power needs and benefit consumers with affordable and reliable electricity.”
Critics, however, have said that could leave the state too reliant on gas, especially when the state could do more to incentivize energy efficiency to reduce demand.
What if conditions get worse?
Below-freezing conditions returned to Texas this month, but not to the same depth and duration as in February 2021.
Experts say it’s only a matter of time until another winter storm hits.
The report from FERC and NERC serves as a warning in case the grid experienced a repeat of Uri, which left millions of people without power for days on end. Researchers examined so-called black-start resources, which can start up without drawing electricity from the grid and are crucial for restoring power after a power system fails.
During Uri, ERCOT had 28 such resources — all of which used natural gas as a primary fuel, according to a 2021 ERCOT report. Nearly three years later, the federal report found, ERCOT still has “limited fuel diversity” and “relies heavily on natural gas” for those resources.
Given that the deep freeze in 2021 dramatically interrupted gas supplies and caused problems in getting gas plants to start up, the reliance on gas could make a grid restart challenging, said Jacobs of the Union of Concerned Scientists.
“The [type of] plants that have gone out are the very ones we’re going to rely on to get the lights back on,” said Jacobs. “What I see is that in a worst-case scenario, there’s no indication that there’s the gas and electric coordination to be able to put the lights back on.”
There are fewer weatherization concerns in the summer, although gas plants have also shown strain during increasingly intense heat waves that have taxed the grid.
The report authors said that beyond diversifying resources, regulators could do more to align the electric and gas industries on a restoration plan. The lack of coordination between the two sectors has been a national issue — including in the Northeast during Elliott — and a focus of FERC officials.
ERCOT did not respond to specific questions about the black-start report.
Lewin said the report illustrates that the grid is better off diversifying, especially with renewables contributing so much during winter storms.
“You have people looking at the role of thermal plants and saying we should use more gas. The conclusion should be the opposite,” he said. “If there’s a problem in the gas system, you end up with massive issues. More diversity of resources gives you a stronger system. Emphasizing gas unwittingly increases your risk.”
Can batteries save the day?
While energy storage numbers remain small, the ability to dispatch batteries at peak times is taking on a growing importance in Texas.
The Uri blackouts prompted a surge in battery investments, as homeowners and businesses sought out an insurance policy in case the grid went down again.
According to the U.S. Energy Information Administration, Texas has the second-most installed battery capacity, with nearly 3,200 MW on the grid as of last November.
That capacity played a key role on the grid — albeit a relatively small one — during the recent winter freeze. According to ERCOT’s Rickerson, batteries provided about 1.5 percent of the total energy needed during peak events during the three days of cold weather.
Rickerson said batteries appeared to be charging during off-peak times and then discharging when demand was higher — or “what you are expecting.”
Those batteries could also play a role as black-start resources. According to the federal report, batteries could provide early support as a power source as well as to maintain frequency and voltage as more resources came onto the grid. However, ERCOT does not include batteries as a black-start resource yet.
The expected growth in batteries to accompany renewables could be threatened by a proposed policy from ERCOT that would have penalized battery operators if they didn’t hold enough charge.
ERCOT officials have warned for months that battery operators needed accountability and regulatory requirements, or else the grid risked them being short when they are needed most.
Specifically, ERCOT said that on two high-demand days last year, battery storage systems were short on charge by as much as 113 MW.
The PUC, however, rejected the most punitive aspects of ERCOT’s proposal earlier this month, voting against penalties for batteries and instead allowing the grid operator to gather more data about how batteries work.
In fact, PUC Commissioner James Glotfelty explained his vote by echoing the concerns about supply risks, saying “every resource fails.”
“Singling out ancillary services providers of battery storage is discriminatory,” he said. “Gas plants fail. Nuclear plants fail. Coal plants fail.”