ERCOT PUBLIC 10/21/ LTSA Update October 21, 2014

ERCOT PUBLIC 10/21/ Outline  LTSA update  Case summary  Reliability analysis results  Next steps

ERCOT PUBLIC 10/21/ LTSA Update  Four scenarios were shortlisted for transmission analysis based on stakeholder feedback  Current Trends (CT)  High Economic Growth (HEG)  Stringent Environmental (SE)  Global Recession (GR)  Reliability cases were prepared per the LTSA scope  Final 2013 RTP case for the year 2018 was used as a start case  90 th percentile load forecast by weather zone was used for the cases  Additional generation was added based on the outcome of generation expansion analysis  Generation siting methodology was used to keep siting consistent across scenarios

ERCOT PUBLIC 10/21/ Case Summary: 2029 Reliability Case (summer peak) ScenarioLoadGeneration*SolarWind CT HEG GR SE *Total generation available for reliability analysis under summer peak condition per the LTSA scope

ERCOT PUBLIC 10/21/ Impact of solar adds  The LTSA scenario assumptions lead to significant solar additions in the next decade  Amount of utility solar increases from 150 MW to about 10,000 MW  Solar output is known to be co-incident with the demand

ERCOT PUBLIC 10/21/ Impact of solar adds on the load shape

ERCOT PUBLIC 10/21/ Reliability Analysis Summary (Preliminary Results) Study Region Constrained Element Scenarios Where Violated Years Where Violated CTSEGR Coast Surfsi – Quintana – Freeport 138-kV Line X XX X X Jordan – Cities – Winfree – Brine – Langston – Mont Belvieu 138-kV Line X X X X Greenbelt – Tejas – Comanche 138-kV Line X X X X Dow 345/138-kV Autotransformers A1 and A2 X X X South Texas – Dow 345-kV Lines X X Peters – Foster – Flewellen 138-kV Line X X East Mt Enterprise – Trinidad 345-kV Line X X Richland – Big Brown 345-kV Line X X

ERCOT PUBLIC 10/21/ Reliability Analysis Summary (Preliminary Results) Study Region Constrained Element Scenarios Where Violated Years Where Violated CTSEGR North Central Hicks Switch – Alliance / Roanoke 345-kV double circuit line XX- - X Benbrook 345/138-kV autotransformers XXX -X Collin Switch 345/138-kV autotransformer #1 XX- XX Northwest Carrollton 345/138-kV autotransformer X - - X Eagle Mountain SES 345/138-kV autotransformers XX- -X Hicks Switch 345/138-kV autotransformer XXXXX Roanoke Switch 345/138-kV autotransformers XXX X Royse Switch 345/138-kV autotransformers X- - X- West Uvalde – W. Batesville 138 kV line XXX Brackettville – Hamilton 138-kV line XX

ERCOT PUBLIC 10/21/ Reliability Analysis Summary (Preliminary Results) Study Region Constrained Element Scenarios Where Violated Years Where Violated CT HE SEGR South La Palma 345/138-kV autotransformer and surrounding 138-kV lines XX XX Loma Alta 345/138-kV autotransformer and surrounding 138-kV lines XX XX South Central Clear Springs - Marion - Skyline 345-kV lineXX Bracken 345/138-kV autotransformerXX

ERCOT PUBLIC 10/21/ Next steps  Complete N-1, G-1 + N-1 and X-1 + N-1 reliability analysis  Compile list of reliability projects for different scenarios  Complete economic analysis  Summarize results in the 2014 LTSA