2009 Scenario Reliability Assessment - NERC

Scenario Reliability Self-AssessmentsScenario Case was about 325 MW higher than the Reference Case while the overall peakdemand forecast was about 120 MW higher than the Reference Case. The primary driver forthese differences was the economic downturn experienced at the end of 2008 and continuing into2009. The Reference Case incorporated this new economic information while the Scenario didnot.The second assumption difference was in the capacity resources recorded throughout the studyperiod. The Reference Case included resources from the 2009 Gold Book that had met specificmilestones as Future Planned resources. Other resources that had not met these milestones,particularly those resources with anticipated in-service dates well into the 10 year study period,were included in the Conceptual category. The Scenario Case included those same resourcesthat met the specific milestones but none that were categorized as Conceptual.Since the Reserve Margin for 2018 is well above the historical requirement prior to the studyaddition of 8000 MW of wind, the amount of internal and external resources required to meetcriteria is not affected by the level of additional wind resources studied. Also, the windresources being studied will not replace any existing resources in the New York Control Area.They may, however, displace the dispatching of existing higher-cost generation.From a resource adequacy perspective, the Scenario Case represents a much more reliablesystem – nominally a 50 percent reserve margin vs. a nominally 30 percent reserve margin.Operationally though, wind presents unique operational characteristics due to its variability, asdescribed elsewhere in this report.The peak demand forecast would need to increase by nearly 25 percent before the ReserveMargin is reduced to 18 percent, the maximum historical value required by the New YorkControl Area.Both the Reference Case and the Scenario Case assumed the same retirements (1093 total MW).There was no impact on reliability due to these retirements.There is no difference in deliverability of resources between the Scenario Case and theReference Case as measured by LOLE. In fact, the beginning assumption is that additionalresources would reduce LOLE. As described above in the transmission study, some amount ofthe wind capacity is “bottled” but that portion which is deliverable from an energy perspectivedisplaces higher cost generation which is primarily gas followed by oil and then coalAs part of its interconnection process all wind plants are subjected to voltage testing. If issues areidentified, the developer is required to install system upgrade facilities such as capacitor banksand SVC to address any issues identified in the interconnection study. As noted above, theNYISO has modified its market rules to accommodate new types of technologies such as flywheels in order for them to participate in the regulation market which one of the NYISO’sancillary services. In addition, the NYISO can increase its procurement of regulation MW ifneeded to meet reliability criteria.As described throughout this document there have been a number changes to the NYISO’smarket structure to address the issues with integrating significant amounts of wind and other2009 Scenario Reliability Assessment Page 99