Texas’ power grid was roughly 4 minutes and 37 seconds away from suffering a total collapse and a near statewide blackout for weeks or more during last week’s deadly winter storm, grid operator officials said Wednesday.
Bill Magness, the president and CEO of Electric Reliability Council of Texas, or ERCOT, detailed this precarious timeline during a meeting with board members while explaining the rationale for ordering rolling blackouts to protect the system from falling below a certain energy threshold.
“If it stays out of balance for too long, as I said, generation units begin to trip off for their own safety,” Magness said, while estimating that the system, which supplies power to roughly 90% of the state, could endure only nine minutes below a constant frequency of 60 hertz before collapse.
In the early hours of Feb. 15, however, the grid did drop below 60 hertz and stayed there for 4 minutes and 23 seconds, he said.
“We could not stay there long. We could not go lower or we would have risked a blackout of the entire system and that is the thing that we cannot allow to happen,” Magness said. “Because if we have a blackout of the system the system is out for an indeterminate amount of time and it’s extraordinarily difficult to bring it back. We may still be here today talking about when is the power going to come back on if we had let the system get into that condition.”
In order to raise the grid’s frequency, grid operators ordered additional blackouts. Magness called this “the only way that we could get back to 60 hertz effectively.”
Though the grid got back to 60 hertz before the nine-minute deadline, the system, which had frozen over in some places, still wasn’t producing enough power to reverse the blackouts ordered. Some people spent days without power. There have been reports of dozens of deaths tied to the storm, though experts have said that it’s too soon to know exactly how many people died as a result of the extreme cold and power outages.
Five ERCOT board members announced they would resign on Wednesday in light of the catastrophic failures. All five of these board members had been criticized for living out of state.
This article originally appeared on HuffPost and has been updated.