NOTICE DATE: November 10, 2022
NOTICE TYPE: M-A111022-01 Operations
SHORT DESCRIPTION: Impact to Supplemental Ancillary Service Market due to Software Error
INTENDED AUDIENCE: All Market Participants
DAYS AFFECTED: October 30, 2022
LONG DESCRIPTION: On Operating Day October 30, 2022, a software error in the Supplemental Ancillary Service Market (SASM) resulted in Responsive Reserve Service (RRS) subtypes in Resources' Current Operating Plans (COPs) not being considered when calculating the Resources' available capacity to provide additional Ancillary Services. This resulted in Ancillary Service awards through a SASM to Resources that did not have available capacity to provide Ancillary Services, as well as incorrect RRS Market Clearing Prices for Capacity (MCPCs). ERCOT was made aware of the error and was able to implement an emergency fix to production systems on Friday, November 4, 2022. Once the error was fixed, ERCOT was able to rerun the SASM in order to determine the correct MCPCs for RRS for the affected Operating Hours. The software only affected the SASM for Operating Day October 30, 2022, and did not affect other applications.
Because ERCOT was not aware of the error until November 4, 2022, ERCOT was unable to determine corrected prices prior to prices becoming final at 16:00 on the second business day after the impacted Operating Day, per ERCOT Protocols Section 6.3. Therefore, ERCOT performed further analysis to determine the significance of the price correction before seeking review of prices by the ERCOT Board, as required by ERCOT Protocols Section 6.3(7)(b).
Specifically, under ERCOT Protocols Section 6.3(7)(b), ERCOT shall seek ERCOT Board review of prices if the change in a Real-Time Market (RTM) Settlement Statement would result in the absolute value impact to any single Counter-Party, based on the sum of all original RTM Settlement Statement amounts of Market Participants assigned to the Counter-Party, to be greater than:
(i) 2% and also greater than $20,000; or
(ii) 20% and also greater than $2,000.
Upon completion of ERCOT's impact analysis, ERCOT has determined that the largest absolute value impact to any single Counter-Party was $146.19, which does not meet the criteria necessary to request ERCOT Board approval for price correction under Section 6.3(7)(b).
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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