1. ERCOT PUBLIC 4/22/2014 1 2014 RTP Inputs and Assumptions April 22, 2014

2. ERCOT PUBLIC 4/22/2014 2 Outline  Initial 2014 RTP case overview  Generation summary  Weather year selection for wind and load in economic analysis  Hydro dispatch in economic analysis  Updates to the RTP scope  Next steps

3. ERCOT PUBLIC 4/22/2014 3 Initial 2014 RTP case overview  The initial 2014 RTP summer peak cases for years 2015, 2017, 2019 and 2020 were created per the RTP scope  “Higher-of” load was used in the summer peak case  Generation was added and retired per the planning guide and RTP scope

4. ERCOT PUBLIC 4/22/2014 4 NCP Load-Generation Balance Summary Year Load* + LossGeneration**MarginImbalance 202089383 80503 1375 10255 201988043 80302 1375 9116 201785069 81382 1375 5062 201582028 80285 1375 3118 * 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

5. ERCOT PUBLIC 4/22/2014 5 Generator addition/retirement summary Site NameCountyCODFuel MW For Grid Sufficient Financial Security Received 2015201720192020 Panda Temple PowerBellAug-14GAS717Yes J.T. Deely 1 & 2BexarN/ACOAL845N/A (Retired in 2018)Yes No Stephens Ranch Wind Energy Phase 1 BordenOct-14WIND201Yes Mesquite CreekBordenJan-15WIND249Yes Longhorn Energy CenterBriscoeDec-14WIND361Yes Cameron County WindCameronJun-15WIND165Yes Panhandle WindCarsonJul-14WIND218Yes Conway WindfarmCarsonDec-14WIND600Yes Hereford WindCastroSep-14WIND200Yes Wake Wind Energy Floyd and Crosby Apr-15WIND299Yes CPV Rattlesnake Den Ph 1 GlasscockMay-15WIND201Yes Miami Wind 1 ProjectGrayJul-14WIND289Yes Panda Sherman PowerGraysonAug-14GAS720Yes Deer Park Energy CenterHarrisJul-14GAS190Yes Rentech ProjectHarrisAug-14GAS15Yes Keechi Wind 138 kV Joplin JackDec-14WIND102Yes Sendero Wind Energy Project Jim HoggFeb-15WIND78Yes Baffin (Penascal Wind Farm 3) KenedyDec-14WIND202Yes OCI Alamo 4KinneyAug-14SOLAR38Yes

6. ERCOT PUBLIC 4/22/2014 6 Generator addition/retirement summary Site NameCountyCODFuelMW For Grid Sufficient Financial Security Received 2015201720192020 Green PasturesKnoxFeb-15WIND300Yes Ferguson Replacement Project LlanoJul-14GAS570Yes Goldthwaite Wind Energy MillsApr-14WIND149Yes Spinning Spur Wind Two OldhamJun-14WIND161Yes Spinning Spur Wind Three OldhamDec-14WIND194Yes Barilla SolarPecosNov-14SOLAR30Yes Route66 WindRandallDec-14WIND150Yes Los Vientos IIIStarrDec-14WIND200Yes Panda Temple Power II BellAug-15GAS717YesNoYes Briscoe Wind FarmBriscoeDec-15WIND300YesNoYes Panhandle Wind 2 (Phase 2) CarsonNov-15WIND182YesNoYes Antelope Station*HaleJun-16GAS359YesNo Patriot (Petronilla) Wind NuecesAug-15WIND178YesNoYes Midway Farms WindSan PatricioOct-15WIND161YesNoYes *359 MWs of antelope station has financial commitment, but ERCOT is working to understand the configuration and availability for ERCOT reliability cases.

7. ERCOT PUBLIC 4/22/2014 7 Generators not added to the cases Site NameCountyCODFuelMW For Grid Sufficient Financial Security Received Windthorst 2ArcherDec-14WIND65No Stephens Ranch Wind Energy Phase bBordenApr-15WIND177No Freeport LNG PreTreatment FacilityBrazoriaJun-17GAS11No Jumbo Road WindCastroApr-15WIND300No South Clay WindfarmClayDec-14WIND200No Logans Gap Wind IComancheMay-15WIND200No Moore Wind 1CrosbyAug-14WIND149No Goldsmith Peaking FacilityEctorJun-15GAS408No Texas Clean Energy ProjectEctorJun-18COAL240No South Plains Wind IFloydJul-15WIND200No South Plains IIFloydDec-15WIND300No PHR PeakersGalvestonApr-15GAS390No CPV Rattlesnake Den Ph 2GlasscockMay-16WIND150No Miami Wind 1 ProjectGrayAug-15WIND111No Pampa Wind ProjectGrayMar-17WIND500No Antelope Station CT1HaleJul-16GAS197No Antelope Station CT2HaleJul-16GAS197No Friendswood Energy GenerationHarrisSep-15GAS316No Pondera King Power ProjectHarrisJun-17GAS1629No Gunsight MountainHowardAug-15WIND120No Cobisa-GreenvilleHuntDec-16GAS1792No Forney Power Plant UpgradeKaufmanAug-14GAS34No White Camp SolarKentOct-14SOLAR100No FGE Texas 1MitchellJun-16GAS799No Mariah WindParmerOct-14WIND232No Mariah WindParmerDec-15WIND200No Mariah WindParmerDec-16WIND168No Comanche Run WindSwisherDec-16WIND500No Mustang Solar ProjectTravisDec-15SOLAR30No

8. ERCOT PUBLIC 4/22/2014 8 Study regions in 2014 RTP  2014 RTP cases will have four study areas North and North Central Coast and East South and South Central West and Far West  Each study region will have its load at the “higher- of” SSWG or ERCOT 90 th percentile load levels

9. ERCOT PUBLIC 4/22/2014 9 Study regions in 2014 RTP Year 2015 RTP load (80512 MW)2017 RTP load (83171 MW) Study regionsN, NCW, FWS, SCE, CN, NCW, FWS, SCE, C Wind output outside of study region (MW) + 464 810889 1335 1137 871 889 1370 Mothball generation on (MW) 52888 603 590 528 88 603 590 Outside scaling %* 95% 97% 96 % 92%94% 93% 92% Study region load (MW) 27084 5350 1963628081 278765763 20714 28818 Year 2019 RTP load (85963 MW)2020 RTP load (87219 MW) Study regionsN, NCW, F WS, SCE, CN, NCW, FWS, SCE, C Wind output outside of study region (MW) + 1137 871867 1370 1137871 889 1370 Mothball generation on (MW) 528 88 603 590528 88 603 590 Outside scaling %* 85% 89% 87% 86%84%88% 85% 84% Study region load (MW) 285776074 21815 2949828919 6187 2232329790 + Wind output outside study region increased up to the 25 th percentile output * Outside load will be scaled from the “higher-of” load levels

10. ERCOT PUBLIC 4/22/2014 10 Load and wind profile analysis  Economic analysis uses 8760 profile for load (by weather zone) and wind (by plant site)  Normalized load and wind patterns tend to smooth out peaks and valleys experienced in real-time conditions and don’t necessarily correlate well to each other  ERCOT plans to use a representative “weather year” for load and wind profiles in the economic analysis based on an analysis of historical weather year data

11. ERCOT PUBLIC 4/22/2014 11 Weather year selection for economic analysis  ERCOT 50 th percentile forecast is derived from twelve years worth of historic weather and load data  ERCOT planning obtained twelve load forecasts for 2017 (sample year) using weather data from 2002-2013 as the only variable  Load forecast for 2008 weather year was ignored because of the impacts of hurricane Gustav  Annual energy and peak load levels for each of the twelve sample forecasts were compared to the official forecast

12. ERCOT PUBLIC 4/22/2014 12 Annual energy comparison

13. ERCOT PUBLIC 4/22/2014 13 Annual peak comparison

14. ERCOT PUBLIC 4/22/2014 14 Weather year selection for economic analysis  Based on the correlation analysis the 2006 weather year is the most correlated to the 2014 official 50 th percentile forecast with respect to both the peak and monthly energy  AWS Truepower wind profiles from 2006 will be used in 2014 economic analysis

15. ERCOT PUBLIC 4/22/2014 15 Hydro dispatch in economic analysis  Hydro dispatch from 2003 through 2013 was analyzed  Data shows that most hydro units have some output, even in 2011  ERCOT plans to use a 8760 profile for each hydro unit  The 8760 profile will be created based on historical dispatch for the representative weather year  ERCOTs representative weather year analysis identified 2006 to be the representative year

16. ERCOT PUBLIC 4/22/2014 16 Updates to RTP scope  Solar plant dispatch in reliability analysis has been changed to 70% from a previous 50%. This was done based on a percentile/confidence analysis using Solar curves data (similar to what was done for wind)  The horse hollow plant will still be connected to Kendall and not to West Texas.

17. ERCOT PUBLIC 4/22/2014 17 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