NOTICE DATE: October 8, 2024

NOTICE TYPE: M-A100824-01 Operations

SHORT DESCRIPTION: Investigation of Incorrect Reliability Unit Commitment (RUC) Opt-Out Snapshot Logic Issue

INTENDED AUDIENCE: All Market Participants

DAYS AFFECTED: To be confirmed

LONG DESCRIPTION: ERCOT has identified an issue in the logic of the Opt-Out Snapshot used to determine whether a Resource will opt out of Reliability Unit Commitment (RUC) Settlement. 

NPRR1092, Reduce RUC Offer Floor and Limit RUC Opt-Out Provision, created the Opt-Out Snapshot which is a snapshot a Resource's Current Operating Plan (COP) used to determine whether a resource will opt out of RUC Settlement for a block of RUC-Committed Hours.  The Opt-Out Snapshot is taken at the earlier of:

a) Two hours prior to the end of the Adjustment Period for the first hour of a contiguous block of RUC-Committed Hours; or

b) Two hours prior to the beginning of the hour that is at least N hours prior to the first hour of the contiguous block of the RUC-Committed Hours, where N is the start time of the Resource at the time of the RUC instruction corresponding to the Resource's warmth state.

An issue was identified in the circumstance where the calculated Opt-Out Snapshot time is within the hour of the RUC execution.  In this case, RUC execution time used in determining the Resource's Opt-Out status is not correctly Day Light Saving (DST) -adjusted.

ERCOT is currently investigating this issue, including whether this meets requirements for a price correction, and will provide further communications and next steps when available.

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.

If you are receiving email from a public ERCOT distribution list that you no longer wish to receive, please follow this link in order to unsubscribe from this list: http://lists.ercot.com.

dg