PacifiCorp 2007 Integrated Resource Plan (May 30, 2007)

PacifiCorp – 2007 IRPChapter 7 – Modeling andResource Strategy Risk ReductionAs described above, adding constraints to the reference portfolio results in a higher stochasticcost. Nevertheless, it can be desirable to choose portfolios or resource strategies that may be suboptimalon the basis of expected stochastic cost, but that reduce risk exposure.Several risk analysis portfolios were developed to evaluate the cost versus risk exposure implicationsof specific resource strategies. These resource strategies and the associated test portfoliosare summarized in Table 7.23.Table 7.23 – Resource Strategies and Test Portfolios for Cost-Risk ExposureResource StrategyEliminate market purchases after 2012 to reduce electricity market price riskInclude additional wind (600 MW) to reduce CO 2 , fuel and market price risksLower the planning reserve margin from 15% to 12% to reduce portfolio investment costsRemove pulverized coal plants as an option and fill the capacity gap with other resourcesTest PortfolioRA2RA3RA8RA6At issue is whether the resource strategies increase or decrease risk exposure relative to the referenceportfolio, and by how much. If an extra dollar of PVRR spent on the resource strategytranslates into more than a dollar in risk exposure reduction, then the extra portfolio cost couldbe considered a worthwhile insurance investment for customers. Comparing the PVRR and riskexposure at the $61 CO 2 adder level in these terms yields the following conclusions:• Eliminate market purchases after 2012 (RA2) – this resource strategy lowers total riskexposure; the relative reduction is $4.15 for every additional PVRR dollar spent• Include an additional 600 megawatts of wind (RA3) – this resource strategy lowers totalrisk exposure marginally; the relative reduction is $1.03 for every additional PVRR dollarspent• Lower the planning reserve margin from 15% to 12% (RA8) – this resource strategyraises total risk exposure; the relative increase is $11.93 for every additional PVRR dollarspent• Remove pulverized coal plants as a resource option (RA6) – this resource strategy raisestotal risk exposure; the relative increase is $6.26 for every additional PVRR dollar spentCarbon Dioxide and Other EmissionsThe following tables and figures profile the CO 2 emissions footprint for the risk analysis portfolios,as well as for SO 2 , NO X , and mercury (Hg). For CO 2 emissions, results are shown by CO 2adder level and for two periods, 2007–2016 and 2007–2026. The tables also report the separateCO 2 contributions from generators and market purchases (existing long term purchases, frontoffice transactions and spot purchases). Figures 7.15 and 7.16 show how the cumulative CO 2emission for each portfolio decline as the cost adder is increased.The resource strategies had the following effect on generator CO 2 emissions relative to the referenceportfolio, RA1:171