February 24, 2021 — A confluence of events brought the Texas electrical grid, and more than 4 million residents, to an unrelenting state of emergency for more than 72 hours last week as ERCOT, the entity that manages the electrical grid for most of Texas, struggled with a loss of electricity generation during disastrous weather while facing likely record electricity demand during a Winter storm that prevented quick repair work on machinery.
The Electric Reliability Council of Texas presented a time line of events at a news conference Wednesday morning, formally acknowledging an investigation that’s been underway into circumstances that led to a “massive loss of electricity generation,” as the entity’s board chair put it.
ERCOT Sally Talberg began by expressing sympathy for those whose lives were deeply affected by last week’s power crisis
ERCOT President and CEO Bill Magness said the US Department of Energy, through help from Gov. Greg Abbott and Sen. John Cornyn, gave special permission to exceed EPA pollution limits because of the weather emergency, to bring generating power up to highest levels — adding more than 100 MW to the Texas system.
Meetings of the Texas Energy Reliability Council, which brings together gas and electricity interests, began in the days leading up to the crisis, and “all available generation was ready” on Sunday February 14th.
Meteorologists had predicted on February 3rd that a major cold weather event was on the way, and on February 8th ERCOT warned electricity providers that the event could be severe, Mr. Magness said.
But when the Winter storm arrived its intensity was overwhelming — there was a dramatic difference between last week’s events and those of a winter storm in 2011, which has often been cited lately as a similar situation, most notably, the 2021 storm shrouded the entire state with freezing or near-freezing weather and kept conditions frozen for several days, freezing pipes and preventing safe transportation even for heavy duty equipment meant for field repairs.
Sunday morning, Valentine’s Day, ERCOT and other entities released a conservation request for homes and businesses to conserve energy because peak electricity demand was expected.
At 11 pm “a lot of generation” began to drop off — a “watch” was called at 11 pm as more generation came off — an “EEA 3” ERCOT’s highest-level emergency deignation, was called about 1:23 am — then 10,000 MW rotating outages began about 1:25 am.
That’s when the electricity was shut off for hundreds of thousands of Texans — with many hundreds of thousands more to come — as the agency told electricity providers such as Oncor to cut power to a certain percentage of its customers based on the providers’ percentage of the statewide power market, sparing hospitals, schools, churches and emergency operations centers.
One of the top rules of maintaining a functioning electricity grid in the United States is maintaining a frequency of 60 Hz.
A drop in frequency even just to 59 can put the entire grid in jeopardy and threaten the collapse of the grid, as Dan Woodfin, Senior Director of Operations explained.
And by midnight as Valentines Day turned into Monday February 15th, one after another, 500 and 600 MW power backups were dropping off the system one at a time, forcing a drop in frequency to a precarious 59.302 (just a tiny amount before possibly bringing down the entire statewide electrical system, often referred to as a “blackstart” event, which would be a major statewide disaster).