Texas power system was minutes from total blackout during winter storm
- Feb 26, 2021 7:21 pm GMT
At about 1:51 a.m. Monday, Feb. 15, as the historic winter storm knocked out power plants across Texas and stymied the ability to produce and provide power, the state’s electricity system frequency fell below 59.4Hz—a threshold signaling a dire emergency.
The state’s electricity system can only spend 9 minutes below 59.4Hz before a statewide blackout is imminent—something which can take weeks or longer to fix, according to Bill Magness, CEO of the Electric Reliability Council of Texas, or ERCOT, the state’s power system operator.
Magness said ERCOT only minutes earlier had shed 2,000MW of load from the state’s power system, hoping to alleviate the increased stress on the system—from everyone in Texas cranking their heat—and buy time for more electricity to become available.
Immediately after the system’s crossed below the 59.4Hz threshold, ERCOT shed another 3,000MW of load from system. The decision buoyed the electricity flow for only seconds before it dipped down again, this time to an all-time low 59.302Hz. Just past 1:55 a.m., with about only four minutes and 37 seconds left before a statewide blackout, ERCOT ordered another 3,500MW of load shed.
By 1:57 a.m., the system was back up around 59.7Hz—still an emergency but further away from devastating collapse. At 2 a.m. ERCOT ordered a final 2,000MW of load shed. The system bounced up to 60.1Hz. In only a matter of minutes, ERCOT forced 10,500MW of load off its system, a dumbfounding amount, according to Magness.
The decision traded one catastrophe—failure of the state’s power system—for another—millions of people were now without electricity as record temperatures low temperatures took hold across the state. In Austin, my home base, temperatures dipped as low as 6 degrees. Magness said a system blackout could take weeks or longer to fix.
“We may still be here today talking about when is the power going to come back on,” Magness told ERCOT’s board of directors at a Feb. 24 emergency meeting. The five board members who resigned following the crisis, including Chairwoman Sally Talberg and Vice-Chair Peter Cramton, were in attendance. Cramton called ERCOT's operations team "heroes."
“ERCOT was flying a [Boeing] 747. It had not one but two engines experience catastrophic failure, then flew the damaged plane for 103 hours before safely landing in the [Hudson River],” Cramton said. “In my mind, the men and women in the ERCOT control room are heroes."
Where blame should fall for leaving millions in the cold is now the subject of numerous investigations across several jurisdictions. Jackie Sargent, Austin Energy’s general manager and an ERCOT board member, criticized Magness for failing to communicate ahead of time how severe the storm was going to be—something Magness said ERCOT heard from its meteorologist well in advance. Magness said it was the storm's severity and the Texas power community's lack of weatherization that caused the crisis. In Texas, there are no regulatory mandates that require power plants to build resiliency against extreme weather.
We’ve been here before
There have been many comparisons to what happened between Feb. 15-19 and Texas’ winter storm in 2011, which forced rolling blackouts in freezing temperatures across the state. Magness assured ERCOT's board of directors that 2021's even was much more damaging.
The 2021 storm knocked 3.5-times more generating capacity than in 2011. The 2021 storm also took out nearly double the raw number of power generators. As ERCOT had to enter into load shed, ERCOT requested 5-times as much load shed than in 2011, and it lasted nearly 10-times as long.
Magness said peak demand for power during the 2021 winter storm topped the all-time summer peak record for the state. It's because temperatures stayed so low for so long. In 2011, Austin spent 69 consecutive hours in freezing or subfreezing temperatures. In 2021, the capital city sat through 162 straight hours of such temperatures. Many analysts have warned that these types of storms will become more common as the climate shifts. If Texas is going to remain on its own power island, many state legislators have called for greater regulation in weatherization so similar disasters are avoided in the future.
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