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June 12, 2019

ERCOT expects emergency alerts this summer, rotating outages possible

by Kelso King, Grid Monitor
Source – Grid Monitor
Posted 06/11/2019

Due to continued economic growth, ERCOT is expecting a new all-time peak, 1,300 MW higher than the all-time peak set in July 2018, leading to an expected planning reserve margin of 8.6% for summer 2019. ERCOT expects to implement Energy Emergency Alerts (EEAs) several times this summer, a situation that allows the grid operator to use resources that are only available a limited number of times during those conditions, providing 2,000 to 3,000 MW of additional resources that are only available during an EEA. The specific amount of available resources will depend on what switchable generation and DC Ties have already scheduled on a given day.

ERCOT’s Seasonal Assessment of Resource Adequacy (SARA) contains four scenarios, representing: 1) Expected conditions, 2) Extreme Generation Outages, 3) Low Wind Output, and 4) Extreme Peak Load (due to high temperatures, which are unlikely this summer). Even under the expected normal scenario, there would be -150 MW of supply available for operating reserves, in other words, ERCOT would be on the edge of an EEA. Mr. Woodfin noted that with a combination of extreme scenarios, ERCOT could be forced to implement rotating outages.

Unaffiliated Board member, Peter Cramton asked about ERCOT’s assumptions for demand response.

Mr. Woodfin noted that industrial customers are likely to reduce their demand by several thousand megawatts during the four coincident peaks and this load reduction is already “baked into” the load forecast. However, Mr. Woodfin noted that this is a conservative estimate and probably does not reflect the degree to which demand response would actually be seen, as a result of the new higher, scarcity pricing.

ERCOT does not expect any reliability concerns due to transmission this summer although there may be certain areas that would experience congestion issues, including Far West Texas, as a result of rapid load growth from oilfields and solar generation development in that area. Export constraints are expected in the Panhandle due to the continuing addition of wind generation, with ongoing outages. Localized transmission congestion is also possible in the Hill Country, Corpus Christi, and the Rio Grande Valley.

Mr. Woodfin identified operational changes that have been implemented for summer 2019:

·         Nodal Protocol Revision Request (NPRR) 776 (Voltage Set Point Communication)

·         System Change Request (SCR) 795 (Addition of Intra-Hour Wind Forecast to Generation to be Dispatched)

·         NPRR 901 (Switchable Generation Resource Status Code)

Mr. Woodfin noted ERCOT’s summer preparations, including transmission outage restrictions from May 15 to September 15, enhanced internal communications tools, operator EEA training, and EEA communication training.

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