ERCOT flirted with potential disaster Monday after saying it was short on capacity, but system demand was reduced enough to keep the lights on.
Staff had initially projected demand to exceed available capacity by about 3 GW on Monday, with load totaling 80 GW for the first time. However, demand was as high as 78.4 GW before averaging 78.3 GW during the hour ending at 5 p.m. CT.
ERCOT’s capacity mix heading for Monday | ERCOT
That was enough to set a record for peak demand, just edging out the mark of 78.2 GW set Friday by 61 MW. It’s the seventh time since May that ERCOT has set a new mark for peak demand.
The grid operator’s peak load has averaged over 77 GW every day since July 4 and resulted in records for weekend peak demand Saturday and Sunday. Staff in May said they were expecting demand to peak at 77.3 GW in August.
Staff currently expect demand to crack the 80-GW threshold Tuesday.
ERCOT is operating under the summer season’s fifth operating condition notice (OCN), its lowest-level market communication in anticipation of possible emergency conditions. The OCN was effective Thursday and expires Tuesday.
On Sunday night, ERCOT made a conservation appeal asking Texans and Texas businesses to voluntarily conserve electricity Monday between 2 and 8 p.m. CT. It also issued a watch for market participants because of a projected reserve capacity shortage during the same time frame, saying there was a risk of an energy emergency alert (EEA).
The grid operator said record-high demand — fueled by sweltering heat that has settled over the region since May and led to numerous high-temperature records — and below-normal wind generation necessitated the conservation appeal. Staff said they only expected less than 3 GW of the more than 35 GW of installed wind capacity, about 8%, to show up Monday.
The load projects and available capacity for ERCOT Monday morning | ERCOT
Solar again provided more than 9 GW of energy during the day, about 81% of its capacity, before the wind picked up later in the afternoon. ERCOT also deployed 663 MW of non-spinning reserves, the third straight day it has called on the service. It was recalled at 4:38 p.m.
Operating reserves stayed comfortably above 3 GW during most of the day.
ERCOT’s operations center sent the watch notice to market participants at 9 p.m. Sunday. Underscoring the gravity of the situation, it followed by minutes the conservation appeal that was the first public communication since ERCOT tweeted out a conservation statement in May that was later termed “just a request.” (See ERCOT, PUC Say Texas Ready for Summer.)
The grid operator said conservation is a reliability tool that it has deployed more than four dozen times since 2008. It is issued when projected reserves may fall below 2.3 GW for 30 minutes or more.
A watch indicates that reserves may fall below a 2.3-GW threshold and are not expected to be recovered within 30 minutes. The next step is a Level 1 EEA under which ERCOT can call on power supplies from other grids and anything else that is available.
The grid operator set four marks for peak demand in June, the last coming on June 23 at 76.6 GW. The previous record had been 74.8 GW, set in August 2019.
Much of the state remains under heat advisories as a ridge of high pressure sits over the Southwest. Houston smashed a record that dated back to 1909 on Sunday when temperatures reached 109 degrees Fahrenheit, 4 degrees higher than the previous mark.
Almost all of Texas saw triple-digit temperatures again on Monday.
Prices in the day-ahead market were going for $2,000/MWh. They hit a peak of nearly $745/MWh around 2 p.m.
