Grid was minutes from total failure
Last week’s winter storm brought the Texas grid minutes away from a “black start” event that could have taken weeks to fix, grid operators said during an emergency meeting Wednesday.
A black start would have plunged the entire grid into frigid darkness indefinitely, taking cell service along with it while the Electric Reliability Council of Texas worked to rebuild the sysem.
“I think it’s important the public understand, ERCOT was flying a 747,” said
Peter Cramton, who likened ERCOT staff to airtraffic controllers. “It had not one but two engines experience catastrophic failure, then flew the damaged plane for 103 hours before safely landing in the Hudson. In my mind, the men and women in the air traffic control room are heroes.”
Cramton, who was ERCOT’s vice chair, and Chair Sally Talberg stepped down following the meeting. Also stepping down were board members Raymond Hepper, Terry Bulger and Vanessa AnesettiParra, according to the
Public Utility Commission, which oversees the grid manager.
The meeting came a week after a historic winter storm forced statewide blackouts, disrupted water supplies and left dozens of people dead.
“We regret that this event took the time it did to resolve,” said Bill Magness, ERCOT’s president and chief executive. “And in this presentation we’ll try to explain what we saw.”
Magness said the extreme cold knocked about half of the grid’s electricity generation, about 52,277 megawatts of 107,514 megawatts of total installed capacity, offline. Pressed for more details about the generation failure, Magness said he’d have more details once power generators respond to ERCOT’s information requests.
Because so many power plants were forced to shut down, electricity suppliers weren’t able to rotate outages as they have during past events, Magness said. The amount of electricity they were required to shed from the system through forced outages was too much to move around, he said.
“Some customers were stuck in that load shed for the entire time,” he said. “That’s where so much of the harm and damage came from. And this is something we have to figure out.”
At the same time, demand surged to new heights.
“Texas has never come anywhere close in the winter to using the amount of load that would have been on the system if we had not had to shed load,” Magness said, pointing out that the outages helped reduce pressure on the system. ERCOT estimates that demand would have been nearly 80,000 megawatts of demand, rivaling summertime records.
Magness also pointed to the differences between last week’s storm and the one in 2011 that forced 14,700 megawatts offline, versus the whopping 52,277 megawatts offline at its peak last week.
“Temperatures did not come up very far or very fast,” last week, he said. “We held onto this cold period for longer than we did in the 2011 event.”
ERCOT will need to rethink how it does its forecasting, Magness said, finding ways to account for extremes.
“This is the kind of event that moves the goal post,” he said
Responding to complaints about communication during the storm, Magness said the question everyone wanted answered was when blackouts would end. And all ERCOT could say was when power generators come back online. “That of course was not a satisfactory answer to people who have been sitting in the cold.”
Magness said he could have better emphasized the anticipated severity of the storm in meetings, but at that point — before ERCOT knew so much power generation would come offline — it appeared the grid could handle what was coming.
“What we were seeing at that time, we believed we could manage with rotating outages that were not extreme,” he said.
Then, he said, “one generator after another reported they were tripped off.” About 33,343 megawatts fell offline as of 1:23 a.m. Monday, or enough to power 6.7 million homes.
Later this week, Magness will testify during two legislative hearings on the issue.