Comparisons of CDR Report and Transmission Planning Models Transmission Planning Models CDR Report SSWG Models RTP Reliability Models RTP Economic Models Provide power flow cases for Provide a power flow case for Provide an estimate of the Provide a range of power flow use in developing the use in developing the planning reserve margin cases with a common Purpose reliability portion of the economic assessment portion during summer and winter reference point for ERCOT and ERCOT Regional Transmission of the ERCOT Regional peak load seasons Market Participants Plan (RTP) Transmission Plan (RTP) Load Forecast Inputs Preparer ERCOT TSPs ERCOT and TSPs ERCOT Four seasons for current year Summer peak for future Years Full year hourly analysis for Summer peak for next 6 Season Summer and Winter 1, 3, 5, and 6 Future Years 3 and 6 years Minimum load and high wind for a future year Higher of: Summed TSP SSWG case loads in each weather zone; “Average” weather in each Average weather or weather zone Weather Assumptions (expect actual load to exceed Varies by TSP, see Appendix A ERCOT 90th percentile (expect actual load to exceed forecast one out of two years) forecast by weather zone forecast one out of two years) (expect actual load to exceed forecast one out of ten years) Based on ALDR forecast, TSPs Peak load by individual Coincident use varied methods for substation for each weather Non-Coincident by weather Load Coincidence (single peak load hour for populating loads by individual zone (non-coincident), with zone ERCOT Region) substation (see Appendix A for exceptions made depending description by TSP) on the case
Comparisons of CDR Report and Transmission Planning Models CDR Report Transmission Planning Models SSWG Models RTP Reliability Models RTP Economic Models Purpose Provide an estimate of the planning reserve margin during summer and winter peak load seasons Provide a range of power flow cases with a common reference point for ERCOT and Market Participants Provide power flow cases for use in developing the reliability portion of the ERCOT Regional Transmission Plan (RTP) Provide a power flow case for use in developing the economic assessment portion of the ERCOT Regional Transmission Plan (RTP) Load Forecast Inputs Preparer ERCOT TSPs ERCOT and TSPs ERCOT Season Summer and Winter Four seasons for current year Summer peak for next 6 years Minimum load and high wind for a future year Summer peak for future Years 1, 3, 5, and 6 Full year hourly analysis for Future Years 3 and 6 Weather Assumptions Average weather (expect actual load to exceed forecast one out of two years) Varies by TSP, see Appendix A Higher of: Summed TSP SSWG case loads in each weather zone; or ERCOT 90th percentile forecast by weather zone (expect actual load to exceed forecast one out of ten years) “Average” weather in each weather zone (expect actual load to exceed forecast one out of two years) Load Coincidence Coincident (single peak load hour for ERCOT Region) Based on ALDR forecast, TSPs use varied methods for populating loads by individual substation (see Appendix A for description by TSP) Peak load by individual substation for each weather zone (non-coincident), with exceptions made depending on the case Non-Coincident by weather zone
PLWG_CDR_Planning_Model_Whitepaper.ROS_Endorsed_July_9__2015.docx