NOTICE DATE:  September 28, 2012

NOTICE TYPE:  W-A09282012-01 Settlements

SHORT DESCRIPTION:  Issue with Real-Time Energy Trades for Operating Day September 18, 2012

INTENDED AUDIENCE:  QSE Settlement Personnel

DAY AFFECTED:  Operating Day September 18, 2012

LONG DESCRIPTION:  An ERCOT system issue impacted the Energy Trade quantities reported to the Lodestar settlement system.  This issue impacted only Operating Day September 18, 2012.  As a result of the ERCOT system issue, Qualified Scheduling Entities (QSEs) were either overcharged for Real-Time Energy Imbalance Service or overpaid for Real-Time Energy Imbalance Service.  ERCOT is investigating the root cause of this issue and will provide additional details in a subsequent Notice once that investigation is complete.

The ERCOT system issue resulted in an impact greater than 2% of the total payments due to ERCOT for the Real-Time Market (RTM) for Operating Day September 18, 2012.  Pursuant to paragraph (2) of Protocol Section 9.5.6, RTM Resettlement Statement, ERCOT will issue a RTM Resettlement Statement for this Operating Day due to the data error.

The RTM Resettlement Statement will appear on the same RTM Invoice as the Initial Settlement Statement for this Operating Day.

ERCOT Credit is reviewing the issue as well and is making manual changes to the Available Credit Limit (ACL) to prevent negatively impacting Counter-Parties as a result of any inadvertent overcharges.  Due to system constraints; ERCOT Credit is only able to adjust the dollar values associated with the RTM settlement activity.  The Aggregate Incremental Liability (AIL) Detail Report will reflect incorrect values for the following fields: QSE to QSE Purchases, QSE to QSE Sales, Imbalance Volume, and Imbalance Amount ($).  The Imbalance Amount ($) will be corrected and reflect in the RTL Adjusted field of the AIL Detail Report.

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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