This Market Driver Alert (MDA) investigates the Energy Emergency Alert 2 issued by ERCOT on September 6th, 2023 and the response of wind and thermal generation in the South & Coastal zone.
On September 6, 2023, ERCOT experienced the tightest grid conditions since Winter Storm Uri when Physical Response Capability (PRC) hit a minimum of 2.1 GW at 19:40. PRC dropped rapidly enough that ERCOT blew through an Energy Emergency Alert 1 (EEA1) and went directly into an EEA2, reigniting post-Uri concerns as to how the grid ended up in emergency conditions with lower load and net load levels than seen in August. Live Power 60-second wind generation in the Coastal and South zones shows wind output drop 761 MW in 30 minutes across 12 facilities. Shortly after, frequency began to decline, reaching a minimum of 59.77 Hz at 19:25. Live Power wind data also shows that the dip in generation was not correlated to weather-related wind decreases, and was not the result of economic curtailment as location marginal prices (LMP) were >$1000. Instead, the drop appears to be correlated to CALAVERS-PAWNEE 345KV PAWNEE_SPRUCE_1 constraint with contingency DELMSAN5 (Elm Creek-San Miguel), of which Live Power monitors both transmission lines.
Figure 1: Live Power 60-second Coastal/South wind generation vs. ERCOT frequency, HE 18-HE 24 on Sept. 6, 2023
Digging into the 60-second generation & transmission data from Live Power we will uncover how different resource groups responded to the EEA2 and what their link is to congestion in the area.