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NOTICE DATE: July 30, 2020


SHORT DESCRIPTION: NPRR833 Implementation Error Identified


DAYS AFFECTED: Operating Day July 31, 2020

LONG DESCRIPTION: ERCOT discovered an error associated with the implementation of NPRR833, Modify PTP Obligation Bid Clearing Change, which went into effect on April 5, 2019.  When ERCOT implemented NPRR833, it erroneously kept in place programming that could cause Point-to-Point (PTP) Obligation bid awards to be improperly deleted after they cleared in the Day-Ahead Market (DAM) optimization. In order to align ERCOT systems with the intended NPRR833 implementation, ERCOT instituted a code change to remove the erroneous programming, which will be effective as of the DAM for Operating Day July 31, 2020.

By way of background, ERCOT implemented NPRR827, Disallow PTP Obligation Bid Award where Clearing Price exceeds Bid Price by $0.25/MW per hour, by adding a deletion script to ERCOT’s systems that removed, after the DAM optimization, any cleared Point-to-Point (PTP) Obligation bid awards that exceeded the bid price by $0.25/MW per hour. Upon implementation of NPRR833, this deletion script became unnecessary and should have been removed from ERCOT’s systems, because NPRR833 modified the DAM optimization engine to prevent a PTP Obligation bid from being awarded in the optimization at a price exceeding the bid price. However, this deletion script was not removed but was instead altered so that it would remove, post-optimization, cleared PTP Obligation bid awards that exceeded the bid price by $0.01/MW per hour.  ERCOT has discovered that, due to this deletion script remaining in ERCOT’s systems, a PTP Obligation bid award was improperly deleted in March 2020 after it cleared in the DAM optimization.  This occurred because the DAM price floor (-$251/MWh) was applied to the sink Settlement Point Price of the awarded PTP Obligation bid after the optimization, but before the deletion script was applied.  Application of the DAM price floor caused this PTP Obligation bid award to be priced in excess of its bid price, which then caused the deletion script to improperly remove the award before it was published to QSEs. 

ERCOT is in ongoing discussions with stakeholders as to how to best address concerns related to the application of the DAM price floor to PTP Obligation awards which, as noted above, may result in an award being priced in excess of its bid price post-DAM optimization.

ADDITIONAL INFORMATION: ERCOT intends to discuss the issue addressed in this Market Notice with stakeholders at the Wholesale Market Subcommittee meeting on August 5, 2020.

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 [log in to unmask].

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