Monday February 8 was a nice day in Dallas. The high that day was 68 degrees and the low was 43 degrees; not bad. But the rest of the week — the next five days through Saturday February 13 — was chilly. The daily highs were 39, 34, 30, 28 and 36 degrees and the lows were 32, 28, 25, 25 and 21 degrees.
Then it got seriously cold in the Big D. The high on Sunday February 14, Valentine’s Day, was 21 degrees but the low was 10. And it snowed, heavily, a good day to stay inside for more than one reason. It kept snowing overnight, with the temperature at 9 to 10 degrees.
That’s when you know what hit the fan. In the zero hour Central Time, on Monday February 15, ERCOT total demand and total generation were both around 65 thousand megawatt-hours. Same was true during the first hour.
During both hours, the zero and first hours, ERCOT total natural gas generation was steady at between 42 to 43 thousand, total coal generation was steady at around 11 thousand, and total wind generation was steady at a bit over 5 thousand.
In the second hour, ERCOT total demand and total generation fell by about 2 thousand megawatt-hours, as did total natural gas generation. Coal generation increased slightly and wind generation decreased by about 1 thousand. Something must have been happening at the end of the second hour, since in the third hour things fell off a cliff.
The third hour of February 15 wasn’t a good one for ERCOT. Total demand and total generation collapsed by approximately 9 thousand megawatt-hours, reportedly by deliberative actions by ERCOT. Total natural gas generation collapsed too, by well over 7 thousand.
Coal and wind generation figured in the fall too, but as no more than minor factors. Total coal generation decreased by less than 2 thousand and wind by less than 1 thousand.
Evidently, the natural gas generation system in ERCOT encountered problems it could not overcome that led to the system operator’s actions. To claim that wind generation was more than a minor cause during the first few hours of February 15 isn’t supported by the data.
However, once there was substantial demand forced off the grid that night, bad stuff kept happening throughout the day. In the case of wind generation, ERCOT average hourly wind generation on the fifteenth was just 3 thousand or so, and in one hour was as low as 650 megawatts. In comparison, for days in the first half of February 2019 and in the first half of February 2020, average hourly generation was generally up in the range of 7 to 19 thousand, and the minimum hour was generally up in the range of 2 to 10 thousand.