EnergyTexas Grid Was 4 Minutes and 37 Seconds from a Statewide Blackout, Per ERCOT

The Electric Reliability Council of Texas held an emergency meeting on Wednesday and provided more detail into last week's events.
February 24, 2021
The frozen hell which fell upon Texas last week was very nearly “catastrophic,” according to the Electric Reliability Council of Texas (ERCOT) during its emergency meeting on Wednesday.

Texas’ grid was four minutes and 37 seconds away from a “black start” event whereupon the entire system would’ve needed to be restarted entirely — and to a large extent, manually. 

This could have yielded even wider-spread blackouts lasting weeks, not days, ERCOT President Bill Magness warned.

On ERCOT’s avoidance of that doomsday scenario, outgoing Vice-Chair Peter Cramton stated, “ERCOT was flying a 747 with not one but both of its engines out and guided it [for days] before safely landing it in the Hudson. The people in the ERCOT control room are heroes.”

“Our job is to provide explanations, not excuses,” said Magness. “And to find ways to prevent this from happening in the future.”

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While much of the general information and timeline were already known, ERCOT provided more details into how last week’s turmoil unfolded.

The cliff-hanging moment came around 1:50 a.m. on February 15. The transmission frequency which normally operates around 60 Hertz (Hz) dropped below 59.4 Hz for over four and a half minutes.

Shortly before then, ERCOT began instituting rotating outages that turned into prolonged blackouts.

In ERCOT’s estimation, if frequency remains below that line longer than nine minutes, the volatility from its mean can rupture the alternating current (AC) connections and create very real equipment and infrastructural damage.

Graph courtesy of ERCOT

The damage this kind of frequency change can cause also occurred in the 2010 Stuxnet cyberattack on various Iranian nuclear facilities. In addition to software disruptions, the computer malware vacillated the operating frequency of hardware to a point where the equipment’s fuses blew, rendering them inoperable and requiring substantial repair.

In effect, only on a much larger scale than a handful of facilities, this is the iceberg ERCOT says it narrowly avoided.

The reason the frequency fluctuated to such a degree — while small in count, the 0.6 Hz change is massive in effect — was that demand came closer and closer to outpacing supply. Throughout February 14 and into the next day, ERCOT monitored the winter storm and its effects on the grid.

Generation began falling off the grid due to the consequences of extreme weather on infrastructure, generators, and at the source.

At its peak, the amount of usual generation out-of-commission due to severe weather was 48.6 percent of the total capacity — equaling over 52,000 megawatts (MW).

One MW can power a few hundred houses at a time.

By source in raw capacity, more natural gas generation tripped offline than any other source with wind generation coming close behind. But by percentage of capacity, 60 percent of wind generation capacity was entirely out of commission while 56 percent of natural gas capacity tripped offline.

Compounding that, however, was the lagging production of the wind power that wasn’t frozen but failed to produce anyway. During the most pressing three-day stretch right after the initial load-shedding, wind generation did not produce more than 5,000 MW from 5:00 a.m. Monday morning until 5:00 a.m. Thursday morning.

During that time, at its lowest moment of raw generation, natural gas still accounted for 60 percent of the electricity generated on the ERCOT grid.

When pressed about the wait to ask the public to reduce their use, thus lessening the grid’s burden, Magness said they waited so the request wouldn’t lose its effect. Had it been issued too early, he posited, the public might have lost sensitivity after some time before the rough waters calmed.

One aspect of this, however, is that when the emergency conditions were issued, it was already after midnight. Most households were already asleep and unable to respond in kind. The request for conservation was issued at 8:35 p.m. on Sunday, February 14. But that does not carry the kind of weight an emergency alert does — nor is it likely that many people saw the conservation request before they hit the hay.

The emergency alert level one is not triggered until reserves dip below 2,300 MW.

Further in his presentation, Magness juxtaposed last week’s situation with that of 2011’s cold snap-induced blackout that lasted a handful of hours.

Chart courtesy of ERCOT

In every measurable category, the 2021 winter storm stressed the grid and its infrastructure substantially more than a decade ago. The days-long cold spell was a rare event both in its severity and its length. Temperatures not only dipped lower last week compared with 2011 but lingered at those subfreezing temperatures for far longer.

Not only will those functional shortfalls be examined, but so will the financial impacts as well. As scarcity swelled so did the prices on the wholesale market. Some Texans have already received astronomical utility bills for their service during those few days, for those many customers with fixed-rate utility plans who will not, their utility company will be stuck with the cost.

The City of Denton, which operates a municipal utility service rather than allowing competing private services, is stuck with a $207 million utility bill for the few days of turmoil. Private retail companies throughout the state will find themselves in a similar situation.

State leaders have already indicated their intention to alleviate the cost burden in some facet.

The investigations are underway and many different policy proposals have been suggested. Both legislative chambers have committee hearings set for Thursday to inquire further about the events that transpired the week Texas’ lights were knocked out.

After the meeting, the resignations of five out-of-state resident board members became effective, including both the chair and vice-chair.

Read the public comments submitted to ERCOT from Texans here.


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Brad Johnson

Brad Johnson is a senior reporter for The Texan and an Ohio native who graduated from the University of Cincinnati in 2017. He is an avid sports fan who most enjoys watching his favorite teams continue their title drought throughout his cognizant lifetime. In his free time, you may find Brad quoting Monty Python productions and trying to calculate the airspeed velocity of an unladen swallow.