AUSTIN — Several reports on the reliability of the Texas electric grid, including one by the Electric Reliability Council of Texas, found blackouts may still occur in worst case scenarios despite infrastructure improvements.
The ERCOT report, released Nov. 19, found that the state’s grid will have sufficient capacity to keep the lights on from December-February, accounting for peak demand and average weather conditions. But in extreme scenarios — the report evaluated five — the state could fall short of needed power.
The reports highlight the state's vulnerability to winter storms like the one in February that caused a catastrophic electric system failure, leaving as many as 5 million Texans without power, some for multiple days. By July, officials had attributed 210 deaths to the storm, and in early November the Texas state comptroller estimated the storm and grid failure caused between $80 billion and $130 billion in damage.
“[The report] serves as a situational awareness tool for ERCOT operational planning purposes, and helps fulfill the ‘extreme weather’ resource adequacy assessment requirement per Public Utility Commission of Texas rule,” according to the ERCOT report.
Normal operating measures call for at least 2,300 megawatts in excess energy. If the grid falls below that threshold, other precautions — like asking for Texans to reduce consumption — kick in.
In a scenario where there is a high peak load similar to the one that occurred during the recent winter storm, with extreme outages and extreme low renewable source output the state grid would once again fall short, according to the report.
It also would fall short in any scenario when high peak load occurs while there is low renewable output, which accounted for four of the five scenarios tested.
A second report by the North American Electric Reliability Corporation found another extreme weather event, including extended colder than normal weather, would “pose a risk to uninterrupted delivery of power.”
That report, released Nov. 18, said extreme weather posed the greatest threat to the Texas grid, which could see a 37 percent shortfall during harsh winter conditions.
“Winter weather that exceeds projected conditions can expose power system generation and fuel delivery infrastructure vulnerabilities and challenge electricity system operators’ ability to maintain reliability,” according to the report.
A separate 300-page analysis by NERC and the Federal Energy Regulatory Commission also highlighted the critical need for stronger, mandatory electric reliability standards.
It found that during the winter storm, a combination of freezing and fuel issues caused more than 75% of the unplanned outages. Most of the shortages came from failures in natural gas systems, followed by wind, other generation types, coal and solar, respectively.
“The final report on Winter Storm Uri is a sobering analysis that highlights the significant work that needs to be done. I previously committed to take the recommendations seriously, and I plan to do exactly that,” FERC Chairman Rich Glick said in a news release. “The devastating effects of extreme cold on our bulk power system’s ability to operate in 2011 and now, 2021, must not be allowed to happen again. We have a duty to protect the bulk power system and public safety and we will do just that.”
ERCOT manages the Texas grid including flow to more than 26 million Texas customers — representing about 90% of the state’s electric load, according to its website. After the deadly and damaging February winter storm, it has been under a microscope with new board members and directives from state leaders.
Texas A&M University Professor of Electrical and Computer Engineering Tom Overbye said work to address grid shortcomings isn't over, but lessons can and have been learned from the winter storm to shore up the reliability of the grid moving forward.
“The grid is certainly getting much better prepared for a winter storm like Uri,” Overbye said.
For example, the Texas Railroad Commission now requires gas supply chain facilities and gas pipeline facilities to “implement measures to prepare to operate during a weather emergency,” in accordance with Senate Bill 3.
“The Commission’s highest priority is to ensure that should another extreme winter weather event occur, all available natural gas under the jurisdiction of the Commission in the state is available to be utilized for reliable energy sources for Texans,” according to an RCC October notice.
To ensure this the RCC is conducting on-site visits to assess preparedness, it said.
In October, the PUC, which oversees ERCOT, adopted a new rule compelling power plant operators and transmission companies to implement new winter weather standards. Affected companies must also attest to the repair of any known, acute issues that arose from the February 2021 storm event, it said. Companies have until Dec. 1 to comply.
PUC members said this is the first of two phases to address weather emergency preparedness. The second phase will come in a future project, officials said.
“This rule is a vital step in our ongoing efforts to harden the grid for future weather challenges,” said PUC Chairman Peter Lake, at the time. “The Legislature made it clear that these companies are accountable for the readiness of their facilities and these rules give them a clear path and incentive for compliance.”
PUC Director of Governmental Relations Mike Hoke said many of the recommendations in the NERC report mirror actions already taken by the PUC and ERCOT based on legislative reform and the direction of the Gov. Greg Abbott “to ensure that we better endure another extreme winter weather event.”
“The Texas power grid is more resilient now than it was going into last winter. We look forward to continuing the partnership with the FERC on resiliency best practices,” Hoke said
But even as the state accelerates efforts to prevent another catastrophe again, Darrian Bertrand, a climate specialist with Southern Climate Impacts Planning Program, said an extreme winter event similar to the February freeze is unlikely to occur for several decades.
She said there were clear issues in the winter storm, but the state and its grid also need to look toward how it addresses extreme heat as that is more imminent with climate change.
In Texas, the number of days over 100 degrees have increased over time, a trend Bertrand said she expects to continue to see. Consequently, with warmer overall temperatures, Texas is less likely to see extreme cold events, she added.
“Texas' climate is really diverse with the drier conditions in the west and wetter in the east, but all of Texas is looking at a much warmer future in terms of both average temperature and extreme heat,” Bertrand said.
PUC officials have said its second phase of rules will address weather-related events at other times in the year including summer.
Overbye, with TAMU, agreed with Bertrand stating that there are other high priority risks that could impact the Texas electric grid more immediately than freezing temperatures such as cyber attacks, electromagnetic pulses and geomagnetic disturbance.
“The thing to keep in mind is that Uri was a very extreme event, something like one in every 30 or 40 years. So people have asked me whether I expect issues this winter and the answer is statistically it's unlikely that we will get that cold,” Overbye said. “My broader concern is on the electric grid, we've got many risks and cold weather is one of them, but there's other risks as well.”