NOTICE DATE: October 24, 2023

NOTICE TYPE: M-B102423-01 Operations

SHORT DESCRIPTION: Board Review of Real-Time prices for October 22, 2023, due to erroneous Security-Constrained Economic Dispatch (SCED) outcomes

INTENDED AUDIENCE: All Market Participants

DAYS AFFECTED: October 22, 2023

LONG DESCRIPTION: On Operating Day October 22, 2023, an issue with ERCOT's Market Management System (MMS) resulted in the Security-Constrained Economic Dispatch (SCED) not being able to consume Three-Part Supply Offers, specifically Energy Offer Curves, and Real-Time Energy Bids for several Resources.  This resulted in SCED failing to produce valid prices for the SCED intervals 12:15 pm - 12:54 pm.  A subsequent related issue caused SCED to fail to run from 12:56 pm – 1:09 pm.

This pricing issue met the initial criteria for the correction of Real-Time prices prior to those prices becoming final.  However, due to an error encountered while processing the price correction data, corrected prices could not be posted before the Real-Time prices of the Operating Day became final at 4:00 pm on October 24, 2023.  

While some additional analysis is still on-going, ERCOT staff believes that the impact of this pricing error meets the criteria for ERCOT Board of Directors (ERCOT Board) review of such prices, as required by paragraph (7)(b) of Protocol Section 6.3.  Accordingly, ERCOT staff intends to seek approval to correct certain Real-Time prices for Operating Day October 22, 2023, at the Reliability and Markets Committee meeting on December 18, 2023, and the ERCOT Board meeting on December 19, 2023. It should be noted that, given the nature of the system issue, the proposed corrected intervals will include a 15 minute period after the first valid SCED run following resolution of the issue, in accordance with paragraph (2) of Protocol Section 6.5.9.2.  Together, the total window of SCED intervals for the price correction review will include intervals 12:15 pm through 1:20 pm.

ADDITIONAL INFORMATION: In addition to the ERCOT Board and Reliability and Market Committee, ERCOT staff intends to present on the potential price correction to the Technical Advisory Committee (TAC) during their next meeting scheduled for December 4, 2023.

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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