Summary of Interim Results*

Resource Adequacy Assessment for 2015Interim ResultsResource Adequacy ForumTechnical Committee MeetingJuly 28, 2010

Summary of Interim Results* • Last calibration of deterministic metrics was done in 2008 • Using 2008 model and data, 2015 summer LOLP is 0% • Using current model and data, 2015 summer LOLP is 5.7%** • What happened? * Results not for distribution** Last year’s assessment implied a 5% LOLP (see next slide) 2

Last Year’s Assessmentfor Summer Peaking Adequacy • Used deterministic metric: Sustained Peak Reserve Margin = 24% • Data used • STM loads • Current non-hydro resources • Old 2008 BiOp and hydro peaking • Calculated SPRM = 24% • Implies a 5% LOLP 3

Major Changes and Effects* • Loads: 2008 used HELM ~ 75% • Hydro: Wind reserves, new BiOp, better bypass spill simulation ~ 20% • Model: better hydro flex operation, LLH and HLH purchase ~ 5% * These percentages are illustrative only 4

Monthly LoadsForecast for 2015 using 1929 Temperatures HELM = EPRI’s Hourly Energy Load Model STM = Council’s Short-term Load Forecasting Model 5

Hourly Peak LoadsForecast for 2015 using 1929 Temperatures HELM = EPRI’s Hourly Energy Load Model STM = Council’s Short-term Load Forecasting Model 6

Hydro Peaking Reduction Compared to 2008 Data (MW) 7

Hydro Peaking Reduction due to Wind Reserve Requirements (MW) 8

Where do we go from here? • Complete review of data and model (fall) • Report interim results • Potential summer peaking inadequacy for 2015 • Caveat: the standard is being reviewed • Finish Phase II of Forum’s work plan (review of methodology by early 2011) • Revise standard, if appropriate (early 2011) • Reassess adequacy (June 2011) 9

Summary of Interim Results*