Proposal to Revise Appendix D of NYSRC Policy 5 Greg Drake Supervisor – Resource Adequacy New York Independent System Operator NYSRC: Installed Capacity Subcommittee (ICS)meeting June 3, 2015 NYISO - Rensselaer, NY

Concern Current Appendix D method adjusts the IRM database when the adopted IRM is lower than the study report value*. The existing method calls for adding EDRP proportional to the existing EDRP. The EDRP program is small and some zones have zero EDRP MWs. *Appendix D also is used when IRM is higher than the report value.

Proposal Change Appendix D to use adjustments based on each zone’s peak load. These adjustments would be part of a new EOP step, and would occur after the current EOP steps.

Conclusion Inclusion of an additional EOP step to align the base case to meet 0.1 LOLE at the 17.0% IRM established value improved the modeling in two significant ways. The MWs needed to get the LOLE back to 0.100 days/year was drastically lower, minimizing any unintended consequences. The number of calls associated with each EOP step is unaffected by the new method.

Proposed language change The last three paragraphs of Policy 5-8, Appendix D: It is understood that in establishing LCRs the NYISO will calculate LCR values, that together with the final IRM, will meet the NYSRC 0.100 LOLE criterion. Since the introduction of a lower IRM into the study’s base case data base could result in a LOLE above the criterion, the data base is adjusted so as to maintain the 0.100 days/year LOLE criterion. This adjustment is accomplished by increasing the EDRP MW values modeled in each zone. by adding a new EOP last step to the other existing steps and populating that step by an increasing amount of MWs. The added MWs are to be in proportion to each zone’s peak load forecast for the upcoming Capability Year.

Proposed language change The last three paragraphs of Policy 5-8, Appendix D-Continued: After completion of the above base case alignment analysis, the NYISO will prepare a report for ICS review., which includes a description of the adjusted EDRP MW values and other assumption changes, the resulting LOLE, and the calculated LCRs. This report shall include the amount of MWs added to each zone, the zonal risk value before and after the adjustment, the resulting NYCA LOLE, and the corresponding MLCRs at the established IRM. After ICS approves the base case alignment analysis, the base case database is provided to the NYISO for use in NYISO studies, including the LCR study described in Section 3.5.5. The aligned base case database is used by the NYISO as a reference for their studies.

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