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NOTICE DATE:  June 1, 2018
NOTICE TYPE:  W-B060118-01 Operations
SHORT DESCRIPTION:  Issue with the implementation of ITCM-104810 to improve the accuracy of indicative Locational Marginal Prices (LMPs)
INTENDED AUDIENCE:  ERCOT Market Participants
DAY AFFECTED:  May 31 through June 1, 2018
LONG DESCRIPTION:  On May 31, 2018 12:00 am, ERCOT as part of Release 3 made two updates to the methodology for calculating indicative LMPs in Real-Time. One of the updates, specifically the new methodology for determining the Generation-to-be-Dispatched (GTBD) that is input for future intervals in the indicative pricing executions, was found to have an issue. This results in an underestimation of the magnitude of system-wide Load changes in future GTBD values. ERCOT has developed a fix for the issue and will be migrating it into production systems and available starting from 15:40 Indicative pricing run execution.  Values posted prior to this fix will not be republished.
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]<mailto:[log in to unmask]>.
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mm