NOTICE DATE: October 9, 2019

NOTICE TYPE: M-A100319-02 Operations

SHORT DESCRIPTION: Potential Price Correction – Modeling of Withdrawn Outages in the Day-Ahead Market and Reliability Unit Commitment

INTENDED AUDIENCE: All Market Participants

DAYS AFFECTED: September 16-23, 2019

LONG DESCRIPTION: On October 3, 2019, ERCOT issued Market Notice M-A100319-01 informing Market Participants that Day-Ahead Market (DAM) prices were under investigation for Operating Days (ODs) September 16-23, 2019.  Therein, ERCOT notified Market Participants that certain withdrawn Outages (i.e., Outages that had been withdrawn before their planned outage start date) were erroneously modeled in the DAM as out-of-service for the affected ODs. In other words, some in-service Transmission Elements were identified as out-of-service in ERCOT’s network model  when clearing the DAM for the affected ODs.

ERCOT has determined that DAM clearing was impacted for all of the affected ODs, and will seek ERCOT Board review of the following DAM prices:

• Day-Ahead Settlement Point Prices (DASPPs);
• DAM Market Clearing Prices for Capacity (MCPCs); and
• DAM Locational Marginal Prices (LMPs) for Electrical Buses.

ADDITIONAL INFORMATION: Supporting documents and re-calculated prices will be included in materials for the December 2019 ERCOT Board meeting.

CONTACT: If you have any questions, please contact your ERCOT Account Manager. You may also call the general ERCOT Client Services phone number at (512) 248-3900 or contact ERCOT Client Services via email at ClientServices@ercot.com.

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