2009 Scenario Reliability Assessment - NERC

Scenario Reliability Self-Assessmentseach other and to the providers’ responsibilities under their Open Access TransmissionTariff is described in a document posted on the WECC Web site. 22In addition to the large number of past and ongoing operating issue studies beingconducted by WECC members, WECC recently created the Variable GenerationSubcommittee (VGS) to coordinate pertinent WECC study efforts and the disseminationof results (both WECC’s and those of members) across the WECC membership. TheVGS is modeled in part on the NERC Integration of Variable Generation Task Force(IVGTF) and has a mandate to address operating, planning, and market issues related tovariable generation in the Western Interconnection, and to interface and coordinate withthe NERC IVGTF. The VGS is in its initial stages of developing work plans. A link tothe VGS home page on the WECC Web site is provided below. 23One of the tasks of the VGS Planning Work Group is to evaluate the various datasources available and studies already performed in order to provide guidance on thereliable capacity that is offered by the various kinds of variable renewable generation inthe Western Interconnection, focusing particularly on wind generation. This wouldenable planners to evaluate the amount of other generation and demand-side resourcesthat need to be put in place to ensure adequacy going forward.WECC does not, at this time, have a program to evaluate the impacts of gasdisplacement by large amounts of variable renewable generation on gas markets, gasprocurement, and other issues raised for the natural gas system. However, the CaliforniaEnergy Commission (CEC) conducted a study in 2007 that examined the natural gasusage impacts of high penetrations of renewables in California, and the entire WesternInterconnection. 24 The report found that with the high penetrations examined, sufficientnatural gas usage reductions were predicted and that overall West-wide natural gas pricedeclines could be expected.The CEC is conducting additional examinations of the impacts of high renewables on thenatural gas system as part of the 2009 Integrated Energy Policy Report proceeding. Aforthcoming CEC staff report suggests that a 33 percent renewable scenario on aninterconnection-wide basis would reduce the predicted average annual natural gas use inthe power generation sector by about 15 percent in the year 2020. This is a comparisonto a Reference Case with renewable resources built out according to currentrequirements. 2522 www.wecc.biz/committees/BOD/TEPPC/default.aspx23 www.wecc.biz/committees/StandingCommittees/JGC/VGS/default.aspx24 “Scenario Analyses of California’s Electricity System: Preliminary Results for the 2007 Integrated Energy PolicyReport, Second Addendum.” CEC, CEC-200-2007-010-AD2-SD. August 2007.25 “Impact of AB32 Scoping Plan Electricity Resource Goals on New Natural Gas-Fired Generation.” CEC, June2009.2009 Scenario Reliability Assessment Page 21