NOTICE DATE: November 7, 2012

NOTICE TYPE: W-A110112-02 Extracts – Wholesale

SHORT DESCRIPTION: Data transparency observations related to time change

INTENDED AUDIENCE: ERCOT Market Participants

DAYS AFFECTED: November 4 – 7, 2012

LONG DESCRIPTION: As a result of ERCOT Daylight Saving Time (DST) observations, ERCOT is reporting the following data transparency issues.

Reports:

The following reports post a seven-day forecast. On October 28, 2012, these reports began omitting data for hour 24:00 of the seventh day. ERCOT is currently working on a resolution to prevent this issue from occurring during the next DST transition.

Report Name	EMIL ID	Report ID
Seven-Day Load Forecast by Forecast Zone	NP3-560-CD	12311
Seven-Day Load Forecast by Weather Zone	NP3-561-CD	12312

Dashboards:

Because of the long day on Sunday, November 4, 2012, there were two displays that duplicated the hourly values for November 3, 2012, and November 4, 2012. In both instances, the November 4 data was correct; however, the November 3 data needed to be regenerated. The November 3 data has been updated and is currently available on the ERCOT.com displays.

Dashboard Name	URL
Real-Time Settlement Point Prices	http://www.ercot.com/content/cdr/html/20121103_real_time_spp
The Actual Loads of Weather Zones	http://www.ercot.com/content/cdr/html/20121103_actual_loads_of_weather_zones

In addition to the updates listed above, ERCOT encountered issues with stale data on the System Ancillary Services Capacity Monitor which also impacted the External Web Services GetSystemParameter request. Stale data was displayed beginning with the repeated 01:00 hour and continued to display until 03:00 for both the System Ancillary Services Capacity Monitor and the Capacity Available to SCED Dashboard.

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].

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