1. ERCOT Monthly Operational Overview (July 2012) August 15, 2012

2. Grid Operations & Planning

3. 3 Content Summary July 2012 Operations –Peak Demand: Actual vs. Forecast On-line Resources: Total at Peak and Wind –CPS1 Monthly Performance –Historical Peak and Minimum Loads –Day-Ahead Load Forecast Performance –Reliability Unit Commitment Capacity (RUC) by weather zone –Generic Transmission Limits (GTLs) –Advisories, Watches and EEAs –Significant System Incidents Planning Activities –Summary –Generation Interconnection Requests –Wind Capacity ERCOT Public August 15, 2012

4. 4 July 2012 Daily Peak Demand: Hourly Average Actual vs. Forecast, Wind Day-Ahead COPs & On-line Capacity at Peak Note: All data are hourly averages during the peak load hour obtained from COPs, and EMMS. ERCOT Public August 15, 2012

5. 5 July 2012 Actual Wind Output plus Curtailments vs. Wind Day-Ahead COPs for All Hours Note: QSEs must use the AWST 50% probability of exceedance forecast as the HSL in their COPs % of Hours when Estimated Uncurtailed Wind Output >= COP HSLs (Target = 50%) 38% ERCOT Public August 15, 2012

6. 6 July 2012 ERCOT’s CPS1 Monthly Performance CPS1 12 Month Rolling Average = 157.90% ERCOT Public August 15, 2012

7. 7 July 2012 Monthly Peak Actual Demand ERCOT Public August 15, 2012

8. 8 July 2012 Monthly Minimum Actual Demand ERCOT Public August 15, 2012

9. 9 Day-Ahead Load Forecast Performance in July 2012 Mean Absolute Percent Error (MAPE) for ERCOT Mid-Term Load Forecast (MTLF) Run at 14:00 Day Ahead 2009 MAPE 2010 MAPE 2011 MAPE 2012 MAPE Jul 2012 MAPE Average Annual MAPE 3.112.83 2.93 2.85 Lowest Monthly MAPE 1.932.241.632.51 Lowest Daily MAPE 0.85 Jul – 21 Highest Monthly MAPE 4.113.793.553.49 Highest Daily MAPE 6.06 Jul – 08 ERCOT Public August 15, 2012

10. 10 Reliability Unit Commitment (RUC) Capacity by weather zone in July 2012 ERCOT Public August 15, 2012

11. 11 July 2012 Generic Transmission Limits (GTLs) GTL: A transmission flow limit more constraining than a Transmission Element’s normal limit established to constrain flow between geographic areas of the ERCOT Transmission System that is used to enforce stability and voltage constraints that cannot be modeled directly in ERCOT’s transmission security analysis applications. Note: This table lists how many times a constraint has been activated to avoid exceeding a GTL limit, it does not imply an exceedance of the GTL occurred. GTLs Jul 11 Days GTLs May 12 Days GTLs Jun 12 Days GTLs Jul 12 Days GTLs Last 12 Months Total Days (Jul11 – Jul12) North – Houston00001 West – North41813 2 Jul(4,23) 185 Valley Import000 0 0 ERCOT Public August 15, 2012

12. 12 Advisories and Watches in July 2012 Advisories issued for Physical Responsive Capability (PRC) below 3000 MW –None Watches issued for Physical Responsive Capability (PRC) below 2500 MW –One Watch for PRC under 2500 MW issued July 30 due to multiple unit trips. Transmission Watches –None Energy Emergency Alerts –None ERCOT Public August 15, 2012

13. 13 Lake Levels Update – 01 August 2012 Surface Water & (MW) *Level @ Full Conservation Pool *Level on Jan 1, 2011 *Level on Oct 7, 2011 *Level on Aug 01, 2012 Lake Texana (56)44.5041.0032.8143.83 Bardwell Lake (312) 421.00 420.71416.23420.00 Lake Colorado City (407) 2,070.20 2057.332052.42050.47 Lake Ray Hubbard (916)435.50432.37429.22433.64 Lake Granbury (983)693.00691.90686.27690.34 Lake Houston (1016)41.7342.1036.7642.40 Twin Oaks Reservoir (1616) 400398.87398.27400.11 Lake Limestone (1689)363359.03354360.65 Martin Lake (2425)306300.48295.06301.32 * In Feet above Mean Sea Level ERCOT Public August 15, 2012

14. 14 Planning Summary – July 2012 ERCOT is currently tracking 133 active generation interconnection requests totaling over 35,000 MW. This includes over 20,000 MW of wind generation ERCOT is currently reviewing proposed transmission improvements with a total cost of $153.7 Million Transmission Projects endorsed in 2012 total $446.7 Million All projects (in engineering, routing, licensing and construction) total approximately $9.77 Billion Transmission Projects energized in 2012 total about $325.7 Million. ERCOT Public August 15, 2012

15. 15 County Location of Planned Generation with Interconnection Requests (all fuels) July 2012 ERCOT Public August 15, 2012

16. 16 County Location of Planned Generation with Interconnection Requests (Wind) July 2012 ERCOT Public August 15, 2012

17. 17 Wind Generation – July 2012 ERCOT Public August 15, 2012

18. 18 Generation Interconnection Activity by Fuel – July 2012 ERCOT Public August 15, 2012

19. 19 Generation Interconnection Activity by Project Phase – July 2012 ERCOT Public August 15, 2012

20. Market Operations

21. 21 Day-Ahead Schedule – July 2012 August 15, 2012ERCOT Public

22. 22 Day-Ahead Electricity And Ancillary Service Hourly Average Prices – July 2012 August 15, 2012ERCOT Public

23. 23 Day-Ahead Vs Real-Time Load Zone SPP (Hourly Average) – July 2012 August 15, 2012 Load Zone West prices were higher due to local congestion caused by transmission outages and low wind in the West Zone ERCOT Public

24. 24 Day-Ahead Vs Real-Time Hub Average SPP (Hourly Average) – July 2012 August 15, 2012ERCOT Public

25. 25 DRUC Monthly Summary – July 2012 August 15, 2012ERCOT Public

26. 26 HRUC Monthly Summary – July 2012 August 15, 2012ERCOT Public

27. 27 Non-Spinning Reserve Service Deployment – July 2012 August 15, 2012 Deployment Start Time Deployment End Time Deployment Duration (Hours) Max Deployment (MW) Reason 7/30 4:06 PM7/30 5:05 PM1.01499Capacity ERCOT Public

28. 28 CRR Price Convergence – July 2012 August 15, 2012ERCOT Public

29. 29 Reliability Services – July 2012 Reliability Unit Commitment (RUC) $ in Millions RUC Make-Whole Payments($0.00) RUC Clawback Charges$0.00 RUC Commitment Settlement($0.00) RUC Capacity Short Charges$0.00 RUC Make-Whole Uplift$0.00 RUC Commitment Cost Allocation$0.00 RUC Decommitment Payments$0.00 RUC Cost continues to trend low. July 2012 cost was $0.002M, compared to: A charge of $0.01M in June 2012 A charge of $0.88M in July 2011 August 15, 2012ERCOT Public

30. 30 Ancillary Services – July 2012 Capacity Services $ in Millions Regulation Up Service$3.0 Regulation Down Service$0.8 Responsive Reserve Service$14.1 Non-Spinning Reserve Service$5.7 Black Start Service$0.6 Voltage Services - Reactive Power$0.0 Voltage Services - Lost Opportunity$0.0 Total Capacity Service$24.25 Capacity Services costs decreased from last month, and are much lower than July 2011. Cost increases observed in the latter days of the month. July 30 - 31 accounted for approximately 30% of the month’s cost. July 2012 cost was $24.25M, compared to: A charge of $34.33M in June 2012 A charge of $49.80M in July 2011 August 15, 2012ERCOT Public

31. 31 Energy Settlement – July 2012 Day-Ahead Market settlement decreased from last month. Real-Time energy settlement decreased from previous month. Decreases are attributable to lower prices. DAM & RTM energy settlement peaked on July 30 - 31. Day-Ahead Market Energy Settlement $ in Millions Energy Purchases$515.30 Point to Point Obligation Purchases$56.85 RMR Day-Ahead Revenue$0.00 Energy Sales($503.55) Day-Ahead Congestion Rent$68.60 Day-Ahead Market Make-Whole Payments($0.30) Real-Time Market Energy Settlement $ in Millions Energy Imbalance at a Resource Node($586.79) Energy Imbalance at a Load Zone$884.37 Energy Imbalance at a Hub($233.95) Real Time Congestion from Self Schedules$0.30 Block Load Transfers and DC Ties($5.70) Impact to Revenue Neutrality$58.22 Emergency Energy Payments($0.03) Base Point Deviation Charges$0.37 Real-Time Metered Generation (MWh in millions)33.81 August 15, 2012ERCOT Public

32. 32 Congestion Revenue Rights (CRR) – July 2012 Auction Disbursements $ in Millions Annual Auction($14.91) Monthly Auction($16.25) Total Auction Revenue($31.16) Day-Ahead CRR Settlement($48.51) Day-Ahead CRR Short-Charges$0.01 Day-Ahead CRR Short-Charges Refunded($0.01) Real-Time CRR Settlement($2.95) Real-Time CRR Short-Charges$0.00 Real-Time CRR Short-Charges Refunded($0.00) Total CRR Proceeds($51.46) Day-Ahead Point to Point Obligations Settlement$56.85 Real-Time Point to Point Obligation Settlement($66.39) Net Point to Point Obligation Settlement($9.54) Congestion Revenue Rights were fully funded. Highest CRR settlement observed on July 21 - 22. Excess funds available for distribution to load. Distribution of balancing account funds to load for July 2012 was $20.14M, compared to: $15.73M in June 2012 $14.94M in July 2011 High excess funds due to separation in West Hub to West Load zone prices August 15, 2012ERCOT Public

33. 33 Revenue Neutrality – July 2012 Revenue Neutrality Settlement $ in Millions Real-Time Point to Point Obligation Settlement ($66.39) Real-Time Point to Point Options and Options with Refund Settlement ($2.95) Real-Time Energy Imbalance Settlement $63.63 Real-Time Congestion from Self-Schedules Settlement $0.30 DC Tie & Block Load Transfer Settlement ($5.70) Charge to Load$11.12 Revenue Neutrality charges to load increased in July 2012. July 2012 was a charge of $11.12M, compared to: $7.03M charge in June 2012 $3.02M charge in July 2011 August 15, 2012ERCOT Public

34. 34 Net Uplift to Load – July 2012 Net uplift to Load decreases over last month. July 2012 was a credit of $2.08M, compared to: A charge of $12.33M in June 2012 A credit of $6.65M in July 2011 Market-Based Uplifts $ in Millions CRR Auction Revenue Disbursement Settlement ($31.16) Balancing Account Proceeds Settlement($20.14) Net Reliability Unit Commitment Settlement$0.00 Ancillary Services Settlement$24.25 Reliability Must Run Services Settlement$0.0 Reliability Must Run for Capacity$0.0 Real-Time Revenue Neutrality Settlement$11.12 Emergency Energy Settlement$0.03 Base Point Deviation Settlement($0.37) Total($16.27) Fee Uplifts ERCOT Administrative Fee Settlement$14.20 Net Uplift Charge to Load ($2.08) August 15, 2012ERCOT Public

35. 35 Advanced Meter Settlement Impacts – July 2012 July 2012: At month end, settling 5.5M ESIIDs using Advanced Meter data. July 2012: 88.9% of the load in ERCOT is settled with 15-min interval data (AMS, Competitive IDR, and NOIE IDR). August 15, 2012ERCOT Public

36. 36 ERCOT Wide Load Volumes by Meter Type – INITIAL Settlement – July 2012 August 15, 2012ERCOT Public

37. 37 Retail Transaction Volumes – Summary – July 2012 Year-To-DateTransactions Completed Transaction TypeJuly 2012July 2011July 2012July 2011 Switches588,755457,57790,42572,044 Move - Ins1,290,3061,247,896212,373191,916 Move - Outs636,806644,162109,055100,829 Continuous Service Agreements (CSA)315,868216,74965,83849,643 Mass Transitions5,51822,0565,5170 Total2,837,2532,588,440483,208414,432 Total since June 1, 200147,762,097 ERCOT Public August 15, 2012

38. 38 Retail Transactions Summary – July 2012 ERCOT Public SwitchesMove-Ins Move-Outs Mass Transition August 15, 2012

39. 39 Retail Performance Measures (Switch) – July 2012 ERCOT Public 1 st Quarter2 nd Quarter 3 rd Quarter 4 th Quarter August 15, 2012

40. 40 Retail Performance Measures (Priority Move-In) – July 2012 ERCOT Public 1 st Quarter2 nd Quarter 3 rd Quarter 4 th Quarter August 15, 2012

41. 41 Retail Performance Measures (Standard Move-In) – July 2012 ERCOT Public 1 st Quarter2 nd Quarter 3 rd Quarter 4 th Quarter August 15, 2012

42. Projects Report

43. 43 ERCOT Portfolio Stoplight Report (as of 8/13/2012) ERCOT Public August 15, 2012

44. 44 ERCOT Portfolio Stoplight Report (as of 8/13/2012) ERCOT Public August 15, 2012

45. 45 ERCOT Portfolio Stoplight Report (as of 8/13/2012) ERCOT Public August 15, 2012