1. ERCOT PUBLIC 5/20/2014 1 2014 RTP Inputs and Assumptions May 20, 2014

2. ERCOT PUBLIC 5/20/2014 2 Outline  Updates to 2014 RTP  Next steps

3. ERCOT PUBLIC 5/20/2014 3 Updates to 2014 RTP: Load  Old load forecasting methodology produced a load forecast which required minor adjustments to align with the planning weather zones  New load forecasting methodology uses inputs which are consistent with weather zone mapping used in planning model  New Load levels are marginally different to the previous values.

4. ERCOT PUBLIC 5/20/2014 4 Updates to 2014 RTP: Non-conforming load identification  RTP Scope document described the methodology to identify non-conforming load as “ERCOT will identify “Flat” load by examining the eight 2013 Data Set A seasonal cases. Any loads that of the eight seasonal loads have a maximum load value to minimum load value of 1.3 or lower will be considered Flat.”  The new process fine tunes identification of such loads by relying more on the TDSP provided data obtained from the operations model.

5. ERCOT PUBLIC 5/20/2014 5 New RTP Load Levels YearCoastEastFar WestNorth North Central South CentralSouthWestNCP 2015 2527926423014166725917131246346233680327 2016 2570126723195170726276134956534242282001 2017 2599926823356175226629138376721240783383 2018 2636626933468174726978142096904245384817 2019 2666727023604180227322145477087247086201 2020 2695327263708182727664148697271247987497 YearCoastEast Far WestNorth North Central South CentralSouthWestNCP 20152527928023014166725417131316512233680159 20162570128093195170725765134956703242281796 20172598928193338173126124138486877242583151 20182636628263468174726463142097086245384618 20192666728313586177926775145637268248885956 20202695328373690180327092148887453249787213 Note: The above tables represents the higher-off the SSWG and 90 th percentile load levels. The numbers in red are 90 th percentile values RTP load presented in previous meeting New RTP load level

6. ERCOT PUBLIC 5/20/2014 6 Generation Updates  714 MW of Bertron units have been added to the mothball list based on the May Capacity Demand and Reserves report  Horse Hollow 1 (HH1) will be connected to Bluff Creek (West) instead of Kendall (south). The rest of the Horse Hollow plants will be connected to Kendall (south) ProjectTotal CapTypeCountyYear updated Weather Zone Windthorst 265Wind Archer2015North Stephens Ranch Wind Energy Phase b 177Wind Borden2015Far West Panhandle Wind 2182Wind Carson2017North

7. ERCOT PUBLIC 5/20/2014 7 Updated NCP Load-Generation Balance Summary Year Load*+ LossGeneration**MarginImbalance 2020 89,56479,2721,37511,667 2019 88,23679,0711,37510,540 2017 85,35180,1511,3756,574 2015 82,21779,5771,3754,014 * Load on this table is the NCP load using higher-of the SSWG or 90 th percentile forecast **This includes generation available as per planning guide section 6.9 with wind and solar dispatched as per the RTP scope with no adjustments to address the imbalance

8. ERCOT PUBLIC 5/20/2014 8 Updated study regions in 2014 RTP + Wind output outside study region increased up to the 25 th percentile output * Outside load will be scaled from the “higher-of” load levels Year 2015 RTP load = 80327 MW2017 RTP load = 83383 MW Study Regions NNCWFWSSCECNNCWFWSSCEC Wind Output Outside Study Region + (MW) 1114 781953 1377 1174 857982 1453 Mothball Generation On (MW) 12427271242 515 12427271242 515 Outside Scaling Percent* 96% 95% 92% 93% 90% Study Region Load (MW) 27584 535019470 27922 28381 576320558 28681 Year 2019 RTP Load = 86201 MW2020 RTP Load= 87497 MW Study Regions NNCWFWSSCECNNCWFWSSCEC Wind Output Outside Study Region + (MW) 1174 857 954 1453 1174 857977 1453 Mothball Generation On (MW) 12427271242 515 12427271242 515 Outside Scaling Percent* 85% 88% 87% 84% 83% 87%85% 82% Study Region Load (MW) 29124 6074 21634 29369 29491 618722140 29679

9. ERCOT PUBLIC 5/20/2014 9 Next steps Case conditioning Initial start cases, contingency list and list of overloads ready N-1 SCOPF analysis G-1 screening followed by G-1+N-1 analysis X-1 screening followed by X-1+N-1 analysis Reliability analysis complete with all reliability issues resolved Economic case preparation Economic analysis Prepare the final RTP report