NOTICE DATE:  June 3, 2011
NOTICE TYPE:  W-A060311-01 Settlements
SHORT DESCRIPTION:  Code change to correct a Settlement System defect
INTENDED AUDIENCE:  CRR Account Holders and CRRAH Settlement Personnel
DAY AFFECTED:  June 6, 2011
LONG DESCRIPTION:  ERCOT has identified a Settlement System defect in the logic that calculates the following bill determinants:

*         RTOPT - Real-Time Option per CRR Owner per pair of source and sink

*         RTOPTR - Real-Time Option with Refund per CRR Owner per pair of source and sink

*         DAOPT - Day-Ahead Option per CRR Owner per source and sink pair

*         DAOPTR - Day-Ahead Option with Refund per CRR Owner per pair of source and sink.
The current logic calculates the RTOPT and RTOPTR by comparing minimum reservation prices with actual Day-Ahead clearing prices to determine how many Options and Options with Refund are settled in Real-Time.  In the event that the minimum reservation price is greater than the clearing price, the current method incorrectly excludes any derated MW of Options and Options with Refunds.
ERCOT has implemented a code change that eliminates the comparison of clearing prices to reservation prices in calculating RTOPT and RTOPTR. The elimination of this comparison is taking place in the Settlement System only. The calculations for RTOPT and RTOPTR will be the Day-Ahead offered MW quantity minus the sum of Day-Ahead awarded MW and derated MW, which are passed to the Settlement System from the Market Management System.
Calculations that use RTOPT and RTOPTR are affected by this issue. These include DAOPT and DAOPTR. The formula used by the Settlement System to calculate the DAOPT and DAOPTR will remain the same, but due to the changes in RTOPT and RTOPTR the calculated values will change. The DAOPT and DAOPTR are calculated in the Settlement System as the total amount of Options and Options with Refund owned by the CRR Owner minus the applicable calculated RTOPT or RTOPTR.
This change will be effective starting Operating Day June 6, 2011.
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]>.

If you are receiving email from an 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<http://lists.ercot.com/>.










dh


############################

To unsubscribe from the NOTICE_SETTLEMENTS list:
write to: mailto:[log in to unmask]
or click the following link:
http://lists.ercot.com/SCRIPTS/WA-ERCOT.EXE?SUBED1=NOTICE_SETTLEMENTS&A=1