NOTICE DATE: November 1, 2012

NOTICE TYPE: W-A110112-01 Extracts – Wholesale

SHORT DESCRIPTION: Potential data transparency issues related to time change

INTENDED AUDIENCE: ERCOT Market Participants

DAYS AFFECTED: November 1 – 4, 2012

LONG DESCRIPTION: As a result of ERCOT Daylight Saving Time (DST) testing, ERCOT has identified potential data transparency issues related to reports and dashboards that may occur during the upcoming time change.

REPORTS:

A change will be implemented today, November 1, 2012, impacting the reports listed in the table below. These reports capture any unconfirmed trades for all remaining hours of the current Operating Day and all hours of upcoming Operating Days. This change may result in one hour of redundant data appearing in reports posted between today’s implementation and the 02:00 CPT transition time on Sunday, November 4, 2012. For example, a report created at 16:05 may contain data on the Hour Ending (HE) 16:00 report along with HE 17:00 forward where the report data should start with HE 17:00. The redundant data will no longer appear in reports posted after the DST transition.

Report Name	EMIL ID	Report ID
Unconfirmed Capacity Trades	NP4-437-CD	13082
Unconfirmed Energy Trades	NP4-438-CD	13083
Unconfirmed Ancillary Service Trades	NP4-439-CD	13084

DASHBOARDS:

Additionally, on Sunday, November 4, 2012, the HE 01:00 and the repeated HE 01:00 may render incorrectly for the dashboards listed in the table below on ERCOT.com and the Market Information System (MIS) dashboards. No manual manipulation will be performed, and the data will continue to display until expired. There will be no impact to associated reports.

Dashboard Name

Real-Time Settlement Point Prices

Load Forecast vs. Actual

Forecasted and Actual Wind Power Production

Market Participants are encouraged not to use the dashboards to make critical market or operational decisions.

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].

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.