Constraints Competitiveness Tests (CCT) – Annual CCT 2013 Study Result with New Approach

Constraints Competitiveness Tests (CCT) –Annual CCT 2013 Study Result with New Approach Market Support and Analysis Wholesale Market Operations

Changes from Current Approach to New Approach ERCOT Public

Implemented CCT Logic for this Study • A constraint is “Competitive” if • Constraint can not be overloaded under worst case scenario OR • Combination of • There are resources with absolute Shift Factor >=2 % • AND positive-SF ECI of squared SF with min(0.02, 1/3) threshold < 2500 • AND negative-SF ECI of squared SF with min(0.02, 1/3) threshold < 2000 • AND no pivotal player exists • Otherwise, it is “Non-Competitive” • An option up for consideration is ignoring the “overloaded under worst case scenario” check • May be appropriate because we are only analyzing one month, which is a peak load month, as oppose to 12 monthly cases ERCOT Public

Constraint Sets and Models used in Annual CCT Study • Models • SSWG 2013 Summer case (dated 2/27/2012) with CRR Annual Auction August 2013 constraint and contingency definitions (dated 9/28/2011) • CRR Auction August 2013 case (dated 7/23/2012) • Basic picture on both models • Total generation capacity about 94,000 MW from registration data • Total load about 74,000 MW from SSWG 2013 Summer case • Entire topology considered, no outages on lines and transformers • Constraint Sets • SCED historical constraints since go-live (693 distinct constraints, all evaluated for both directions) • CSC/CRE (332 distinct constraints, all evaluated for both directions) ERCOT Public

Result on SCED Historical Constraints (Zero-out Negative Wind Flow, ECI Threshold [2000,2500], OL Flag Check) ERCOT Public

Result on CSC/CRE Constraints (Zero-out Negative Wind Flow, ECI Threshold [2000,2500], OL Flag Check) ERCOT Public

Result on SCED Historical Constraints (Zero-out Negative Wind Flow, ECI Threshold [2000,2500], No OL Flag Check) ERCOT Public

Result on CSC/CRE Constraints (Zero-out Negative Wind Flow, ECI Threshold [2000,2500], No OL Flag Check) ERCOT Public

Summary of Study Results – Number of Competitive Constraints ERCOT Public

Inconsistent Results Between the 2 Models (Switch between Competitive/Non-existing and Non-competitive) (Zero-out Negative Wind Flow, ECI Threshold [2000,2500], OL Flag Check) ERCOT Public

Causes of Inconsistent Results between the 2 Models • Actual topology change • Results in shift factor change • Results in ECI change • Line limit change • Results in overload-ability change • Result in PPI change once compared pivotal flow to line limit ERCOT Public

Concerns during Annual CCT Study • DC-Ties (all DC-Ties have been considered in the study with entity as ERCOT) • Only the decision making entity was considered for this study, not Affiliates • Impact of peak load in cases that were studied • Significantly reduced the number of overload-able constraints, • A high-ECI constraint can be competitive just because it won’t be overloaded in the worst case when generators with SF<0 are used to meet peak load • Should negative WGR shift factors be included in the shift factor cut-off even if the MWs are considered to be 0 ERCOT Public

Additional Material ERCOT Public

Summary of all New Study Results ERCOT Public

Results Presented During 8/6 CMWG Meeting • For the results presented at the 8/6 CMWG Meetings, the ECI thresholds that were used were 3000 and 2500 (as oppose to 2500 and 2000) • For the wind capacity ratio • ECI: 0% for the WGRs with shift factors < 0 • PPI: 100% for all (impact on constraint considered to be 0) ERCOT Public

Results Presented During 8/6 CMWG Meeting • Results on SCED Historical Constraints – Overload Check ERCOT Public

Results Presented During 8/6 CMWG Meeting • Results on CSC/CRE Constraints – Overload Check ERCOT Public

Results Presented During 8/6 CMWG Meeting • Results on SCED Historical Constraints – No Overload Check ERCOT Public

Results Presented During 8/6 CMWG Meeting • Results on CSC/CRE Constraints – No Overload Check ERCOT Public

Other Previously Discussed Results • If at another Load Profile - Compared to Previous Study in May 2012 • Out of 542 CSC/CRE constraints, 522 are competitive and 20 are non-competitive with current CCT approach. Note it considers ECI, PPI and worst case flow. • While with proposed min(0.02, 1/3) squared SF approach, out of 542 CSC/CRE constraints, 290 are competitive and 252 are non-competitive. Note it considers ECI, PPI and worst case flow as well. • The competitive ratio for CSC set reduces from 96% to 53%. • Note that this version of result is based on DCCT 11/30/2011. ERCOT Public

Constraints Competitiveness Tests (CCT) – Annual CCT 2013 Study Result with New Approach