1. QSE Managers Working Group Meeting Notes November 10, 2009 Report to WMS November 18, 2009 Jennifer Troutman – Vice Chair

2. QSE Managers Working Group Topics  Wind Plant Availability Website  Wind Generation Forecast Accuracy Analysis  Ancillary Services Procurement Methodology  Load Forecasting Accuracy  Decommitment Process for RPRS

3. Wind Plant Availability Website  Approximately 30 users are entering outages  Difficult to determine how many Market Participants that translates into  Some Market Participants reporting that the AWS outage scheduler can only be used for one hour at a time  For example, for an outage for HE 2-10, 9 separate outages would have to entered  ERCOT going to perform high level review whether data is improving forecast

4. WGRPP Forecast Accuracy Analysis  ERCOT is now receiving good MET data for all points from over 50 WGRs  Additional improvement and increase in the number of points being submitted  ERCOT was to analyze impact of moving from a P80 to P50  Some members may draft PRR to at least change to a P50 forecast in the on peak hours

5. WGRPP Forecast Accuracy Analysis Based on Day Ahead resource plans submitted by QSE’s compared to aggregate WGRPP AWS forecast in order to scale the STWPF. Mean Actual Estimated Output Standard Deviation of Estimated Output ** Mean Absolute MW Error (Abs(Estimated Output - Scaled STWPF)) Mean Absolute Percent Error (Output in Denominator) - (Abs(Estimated Output - Scaled STWPF)/Estimated Output) * Mean Absolute Percent Error (Capacity in Denominator) - (Abs(Estimated Output - Scaled STWPF)/Total Name Plate WGR Capacity) All Hours1816.141423.04697.4592.87%8.24% Off-Peak Hours (1-6,23,24)2230.68 1566.33873.05126.45%10.30% On-Peak Hours (7-22)1608.87 1298.61609.6476.07%7.20% Hour Ending 23-24 and 1-22339.49 1546.13986.7192.78%11.64% Hour Ending 3-62121.86 1585.23759.39160.13%8.97% Hour Ending 7-101743.41 1428.61627.85110.94%7.42% Hour Ending 11-141454.21 1364.51460.8574.02%5.45% Hour Ending 15-181444.21 1140.44583.8656.68%6.91% Hour Ending 19-221793.64 1216.77766.0262.65%9.04%

6. September Data in Histogram Risk of Over Commitment Risk of Shortages

7. WGRPP Forecast  ERCOT is now providing the forecast to WGRs via XML  ERCOT going to issue notice soon that it will discontinue providing it via email  ERCOT Client Services going to poll WGRs to be sure that no one is still using email process

8. Load Forecast Analysis  QMWG going to work with ERCOT to schedule Load Forecasting Workshop  Will coordinate efforts with the PUCT  Reviewed ERCOT’s Replacement Reserve Service Monthly Reports  Going to ask ERCOT SME to review in detail at next meeting

9. Load Forecast Accuracy

10. Hours Ending All Days By SeasonBy YearLast 4 Months Decemb er, January, Februar y March, April, May June, July, August Septem ber, October, Novemb er 200720082009 July '09 August '09 Septem ber '09 Octobe r '09 23-24 and 1-2 3.06%3.33%2.48%3.43%2.94%3.30%3.00%2.93%3.01%3.92%3.09%2.66% 3-62.50%3.77%1.96%2.15%2.43%2.19%2.70%2.50%1.96%2.60%1.84%2.69% 7-102.76%3.71%2.60%2.23%2.77%2.48%2.99%2.70%2.04%1.92%2.02%2.75% 11-143.50%4.84%3.34%2.76%3.49%3.51%3.62%3.35%2.54%2.17%4.02%2.75% 15-184.08%3.95%3.68%4.24%4.34%4.84%3.81%3.78%3.49%3.31%6.20%3.57% 19-224.09%3.21%3.72%4.97%4.09%5.15%3.66%3.76%3.99%4.50%4.92%3.09% All Hours3.33%3.80%2.96%3.30%3.34%3.58%3.30%3.17%2.84%3.07%3.68%2.92%

11. Decommitment Process for RPRS  ERCOT is drafting PRR language for this  Operations Support  Settlements  Market Participants want to focus efforts on creating a Nodal decommitment process

12. Next Meeting  Next Meeting: December 2, 2009  Topics  Wind Generation Forecast Accuracy  Load Forecasting Accuracy  Nodal Decommitment Process for RUC  Wind Generation Nodal Issues