Sep 4, 2013

Impact of NPRR 520 Impact of NPRR 520 (SCED CCT)(SCED CCT)

Market AnalysisERCOT

Background of NPRR 520 (SCED CCT)

Why Change?Why Change? SCED over-mitigation issues

What Changed?What Changed? No Monthly and Daily Constraint Competitiveness Test (CCT) SCED CCT runs every 5 minutes (or whenever SCED is

executed) Less set of Resources get mitigated Minimizing unnecessary Base Point oscillations/QSGR dispatch

System Lambda Increase

Mitigation Ratio

Increased Peaker Net Margin (PNM)

Pivotal Players For Each Active Constraint (7/1-7/30) (Continued)

Pivotal Players For Each Active Constraint (7/1-7/30) (Continued)

Top 10 Non-Competitive Constraints

Constraints with Both Competitiveness Status (7/1-7/30)

CONTINGENCONTINGENCY_NAMECY_NAME

CONSTRCONSTR_NAME_NAME

FROM_SFROM_STATIONTATION

TO_STTO_STATIONATION

FROM_SFROM_STA_KVTA_KV

TO_STTO_STA_KVA_KV

CCT_SCCT_STATUSTATUS

CompetitivCompetitive_Freqe_Freq

NonCompetitNonCompetitive_Freqive_Freq

DENTSCS5 1170__A NCDSE HNRSW 138 138COMP 29 6

DGIBSNG5 240__A JEWET SNG 345 345COMP 26 29

DGIBSNG5 260_A_1 JEWET SNG 345 345COMP 77 18

DJEWSNG5 JK_TOKSW_1 TOKSW JK_CK 345 345COMP 325 30

DNAVWTR5 35040__A NAVARRO VENSW 345 345COMP 2 8

DTB_SNG5 SNGZEN99_A SNG ZEN 345 345COMP 6 926

Summary of Impact of NPRR 520

Average number of mitigated resources for each SCED interval:

Old: 100% vs. New: 4.8%  Average system lambda increase: $0.2/MWh for 744 hours.  Cumulative PNM increase: $80.63/MW.  Total number of non-competitive constraints:  Old: ~100% vs. New: 95%

Next Step

•Shall we use HDL instead of HSL for CCT calculation?

•Shall we include all online Resources’ LDL as base load?

•Shall we use sf*HSL instead of sf*sf*HSL for ECI calculation?

Thanks!Thanks!