PacifiCorp 2007 Integrated Resource Plan (May 30, 2007)

PacifiCorp – 2007 IRPChapter 4 – Resource Needs AssessmentINTRODUCTIONThis chapter presents PacifiCorp’s assessment of resource need, focusing on the first 10 years ofthe IRP’s 20-year study period, 2007 through 2016. The company’s long-term load forecasts(both energy and coincident peak load) for each state and the system as a whole are addressedfirst, followed by a profile of PacifiCorp’s existing resources. Finally, load and resource balancesfor capacity and energy are presented. These balances are comprised of a year-by-year comparisonof projected loads against the resource base without new additions. This comparison indicatedwhen PacifiCorp is expected to be either deficit or surplus on both a capacity and energybasis for each year of the planning horizon.LOAD FORECASTMethodology OverviewPacifiCorp estimates total load by starting with customer class sales forecasts in each state andthen adds line losses to the customer class forecasts to determine the total load required at thegenerators to meet customer demands. PacifiCorp uses different approaches in forecasting salesfor different customer classes. PacifiCorp also employs different methods to forecast the growthover different forecast horizons. Near-term forecasts rely on statistical time series and regressionmethodologies while longer term forecasts are dependent on end-use and econometric modelingtechniques. These models are driven by county and state level forecasts of employment and incomethat are provided by public agencies or purchased from commercial econometric forecastingservices. 26 Appendix A provides additional details on methodologies and state level forecasts.Integrated Resource Planning Load ForecastsThrough the course of the 2007 integrated resource planning cycle, PacifiCorp relied on two loadforecasts for the development of the load and resource balance and portfolio evaluations. Thefirst official load forecast used in this IRP cycle, released in May 2006, was used to support portfolioanalysis from May 2006 to February 2007. Between May 2006 and March 2007, eventstranspired that resulted in the need to revise the load forecast. Because of the magnitude of theforecast changes and the extended IRP filing schedule granted by the state commissions, thecompany decided that it was prudent to incorporate load forecast updates in the IRP. Consequently,PacifiCorp’s IRP analysis from February 2007 onward reflects the new March 2007load forecast.The primary changes to the original May 2006 load forecast result from recent trends and conditionson the east side of PacifiCorp’s service territory. Growth in Utah was slowing from whatwas previously planned; therefore, its growth rates were reduced. This was mainly associatedwith the growth in the commercial class and a slowing of the service activity in the state. Offsettingthis were requests for service in the oil and gas industries of Wyoming. Higher prices, fuelsupply uncertainty both nationally and worldwide resulted in plans to increase the developmentof the fields in Wyoming. Additionally, portions of Wyoming are experiencing air quality problemswith existing extraction practices that require electrification of the existing services in the26 PacifiCorp relies on county and state level economic and demographic forecasts provided by Global Insight, inaddition to state office of planning and budgeting sources.62