Manual HDL/LDL Override Summary

QMWG

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Daily Summary Graph

• For this analysis, we captured unique HDL/LDL overrides– An override is considered unique if that same Resource did not

have an override within the last 10 minutes• There were 20 total unique overrides in July

– As compared to 105 in June and 80 in May

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Daily Summary Table

DateTotal Number of

OverridesNumber of Resources

with an OverrideNumber of Unique HDL/LDL Overrides

Jul 1, 2011 203 1 1Jul 2, 2011 0 0 0Jul 3, 2011 0 0 0Jul 4, 2011 4 2 4Jul 5, 2011 0 0 0Jul 6, 2011 4 1 2Jul 7, 2011 157 1 0Jul 8, 2011 132 1 1Jul 9, 2011 0 0 0

Jul 10, 2011 0 0 0Jul 11, 2011 25 1 1Jul 12, 2011 0 0 0Jul 13, 2011 0 0 0Jul 14, 2011 0 0 0Jul 15, 2011 0 0 0Jul 16, 2011 0 0 0Jul 17, 2011 0 0 0Jul 18, 2011 0 0 0Jul 19, 2011 0 0 0Jul 20, 2011 0 0 0Jul 21, 2011 51 3 3Jul 22, 2011 100 1 1Jul 23, 2011 130 3 4Jul 24, 2011 0 0 0Jul 25, 2011 0 0 0Jul 26, 2011 2 1 1Jul 27, 2011 286 1 1Jul 28, 2011 126 2 1Jul 29, 2011 0 0 0Jul 30, 2011 0 0 0Jul 31, 2011 0 0 0

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Reasons for Manual HDL/LDL Overrides

• An override is considered unique if that same Resource did not have an override within the last 10 minutes

• SPS Activation was the primary reason for the total number of HDL/LDL overrides during the month

• 2 different Contingencies/ Constraints were given as the reason for an override

QMWG 8/8/2011

July 2011 Generation Resource Energy and Regulation Deployment Performance

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Month-to-Month NON-IRR GREDP – Energy Deployments

Resources below 85% threshold

- Resource 1 also failed in June and Resource 2 failed in May and June. Both Resources had similar GREDP scores and intervals scored each month.

Total Intervals Passed Total Intervals Scored Std Dev(GREDP MW) GREDP Monthly Score

4,007 4,865 20.26 82.3675 185 6.47 40.54

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Month-to-Month NON-IRR GREDP – Regulation Deployments

Resource below 85% threshold

- Resource also failed in June with a GREDP of 72%, 28 MW deviation, and was scored 3,640 intervals.

Total Intervals Passed Total Intervals Scored Std Dev(GREDP MW) GREDP Monthly Score3,136 3,842 17.77 81.62

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Month-to-Month IRR GREDP

Resources below 95% threshold- Best month since Nodal Go-Live. Effort to update HSL logic was a key contributor. - 23 resources failed for July. 19 of the 23 also failed in June.

- 3 resources > 50 intervals- Weighted Average – 73%- Average Deviation – 12.5 MWs

IRRs below 95% GREDP thresholdConsecutive Months 8 7 6 5 4 3 2 1Count of Resources 2 11 10 9 16 12 10 9

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IRR Total Intervals Scored – Month-to-Month

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July GREDP by Fuel Type

Count Average GREDP

Average STD DEV

Min GREDP < 85 >= 85 >= 90 >= 95

CC 61 98.60 5.46 93.49 4 57CLLIG 41 99.84 2.83 98.17 41DSL 27 99.99 0.43 99.95 27GSNONR 16 99.11 1.05 95.60 16GSREH 34 97.57 4.07 82.36 1 1 32

HYDRO 20 98.41 1.83 93.83 2 18

SCGT90 25 99.73 1.25 97.35 1 1 1 22SCLE90 91 98.36 1.65 40.54 91WIND 52 78.83 9.63 0 22 1 0 29

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July GREDP Scenario Analysis

NON-IRRs >= 85% < 85% 5 MW - 5% 322 58MW - 8% (Current) 325 2Exclusions - No Freq Dev 325 2

IRRs >= 95% < 95% 5% 28 2410% - 1MW Band when BP = 0 (Current) 29 2310% - 3MW Band when BP = 0 29 2310% - 3MW Band at all times 30 22Exclusions - No Freq Dev 28 24Measured like NON-IRRs (85%) 84 3

QMWG 8/8/2011

Performance Monitoring Process

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Performance Monitoring Process

• Monitor Performance – Protocols Section 8• Investigate possible non-performance• Collaborative effort with Market Participants

– Mid month calls – Review Performance, issues(s), improvements– Respond to requests for information/data

• Informal requests for corrective action(s)– Cause Identified, Mitigation date(s)– Monitor for improved performance

• If required:– Corrective Action Plan, Protocol 8.4 (1)– Possible Disqualification, Protocol 8.4 (2)

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8.4 ERCOT Response to Possible Non-Performance

(1) ERCOT may require a Market Participant to develop and implement a corrective action plan to address its failure to meet performance criteria in this Section. The Market Participant must deliver a copy of this plan to ERCOT and must report to ERCOT periodically on the status of the implementation of the corrective action plan.

(2) ERCOT may revoke any or all Ancillary Service qualifications of any Generation Resource or Load Resource for continued material non-performance in providing Ancillary Service capacity or energy.

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Performance Monitoring Expectations, August 1st

• GREDP Expectations, August 1st– Nodal in its eighth month of stabilization– ERCOT has worked with QSE’s to improve

performance since go-live– Improvements have been implemented

• Curtailment flag (5/18)• Dynamic ramp rates (7/25)

– ERCOT required to identify non-performers to the Texas RE and PUC