2009 Scenario Reliability Assessment - NERC

Regional Reliability Scenario Self-AssessmentsWECC interprets this question to be about local deliverability, rather than about additions to thebulk transmission system addressed in Section 6. Generally, the transmission analysis done forthe LRTA cases is not detailed enough to address deliverability into local load centers from thehigh-voltage grid. In its resource adequacy analysis, WECC considers such issues theresponsibility of the local transmission providers. However, WECC believes that this simplifiedmethod of analysis captures major elements of deliverability tied to the major transmission pathswithin WECC. The question of projected ATC and contractual transmission rights involves datathat WECC does not collect and believes is irrelevant to interconnection-wide reliabilityanalyses.As shown in the Transmission section, major path upgrades would be required to deliver the newrenewable generation hypothesized in the scenario to load centers. If the generation weredeveloped as in the scenario and if that transmission were not constructed, the capacityrepresented by the renewables that would not be deliverable would have to be made up by localgeneration or additional demand-side measures.Generally, the transmission analysis done for the LRTA cases is not detailed enough to addressdeliverability into local load centers from the high-voltage grid. In its resource adequacyanalysis, WECC considers such issues the responsibility of the local transmission providers. Thescenario analysis also is not detailed enough to address distribution deliverability questions.The need for additional operating reserves for balancing within-hour variable generation (such aswind), to ensure meeting the BAL standard, is already becoming a prominent issue for BAs withlarge amounts of variable generation to manage, such as BPA. This is doubly an issue whensubstantial portions of the variable generation are intended to be delivered to loads in other BAs(again, BPA is a prime example). Changes in market structure and mechanisms are being studiedin the Western Interconnection as one means of dealing with this kind of within-hour balancingproblem.2009 Scenario Reliability Assessment Page 175