2009 Scenario Reliability Assessment - NERC

Scenario Reliability Self-Assessmentsnot applied, and unless ISO-NE changes its forward going methodology to determine NewEngland’s annual resource adequacy requirements, they will not apply going forward.The 2018 Summer Reserve Margins for the category Existing Certain and Net FirmTransactions shows a 7.1 percent margin for both the Reference Case and the Scenario Case.This is because both the Reference and Scenario Case have the same assumptions for Existing(Certain & Other) Capacity, Future (Planned& Other) Capacity and Capacity Transactions(Imports & Exports).The 2018 Summer Reserve Margins for the category Total Potential Resources shows a 53.2percent margin for the Reference Case and a 28.0 percent margin for the Scenario Case. Thisdifference is due to the fact that within both the Reference Case and the Scenario Case, 100percent of the identified Conceptual Capacity was added to the Total Potential Resourcesmargins. The Reference Case Conceptual Capacity (12,462 MW) is 7,808 MW greater than thatof the Scenario Case Conceptual Capacity (4,654 MW). The Reference Case Total PotentialResources margin (53.2 percent) is almost twice as much as that of the Scenario Case TotalPotential Resources margin (28.0 percent).The 2018 Summer Reserve Margins for the category Adjusted Potential Resources shows a 20.2percent margin for the Reference Case and a 27.2 percent margin for the Scenario Case. Thisdifference is due to the fact that within the Scenario Case, a 100 percent Confidence Factor (Line16c) was applied to the Conceptual Capacity, thus adding the total amount of renewableresources (4,654 MW) to the Adjusted Potential Resources margins. However, the ReferenceCase only applies a 20 percent Confidence Factor (Line 16c) to the total amount of ConceptualCapacity (12,462 MW), which results in approximately 2,492 MW of resources being applied tothe Adjusted Potential Resources, which results in a margins of only 20.2 percent.New England does not have a particular capacity margin requirement; rather it projects itscapacity needs to meet the NPCC once in ten-year loss of load expectation (LOLE) resourceplanning reliability criterion. 67 The capacity needs to meet this criterion are purchased throughannual auctions three years in advance of the year of interest. For reference purposes, the annualaverage percent capacity needed to meet the resource adequacy planning criterion based on aforecast of representative future installed capacity requirements is approximately 15 percent.Since the primary assumption within the mandate of the Scenario #1 requirement is the anaccelerated integration of new renewable resources, this Scenario Case assumes that all the newrenewable resources (4,654 MW) would be expected to be commercialized within New Englandand operating as designed during the target assessment year 2018. Thus, in this Scenario Caseand similar to that within the Reference Case, there is maximum reliance on both internal andexternal capacity resources, in the year 2018, to be available to deliver their capacity and energyas contractually bound to satisfy their obligations under the FCM.67 To develop installed capacity requirements to meet the once in 10 years disconnection of firm load resourceplanning reliability criterion, ISO New England takes into account the random behavior of load and resources in apower system, and the potential load and capacity relief obtainable through the use of various ISO-NE OperatingProcedures.2009 Scenario Reliability Assessment Page 89