Evaluating Hydro Capacity for Capacity Adequacy Standard: Selection of Hydro Events Mary Johannis PNW Resource Adequacy Technical Committee Mtg November 27, 2007

PNW Resource Adequacy Technical Committee Meeting2 Why Evaluate Hydro Capacity Regional Capacity Adequacy Assessment performed by Council WECC Loads and Resource Reporting by Balancing Authorities PNUCC Reporting Individual Utility Resource Planning

November 27, 2007 PNW Resource Adequacy Technical Committee Meeting3 Steps to Finalize Capacity Adequacy Standard Validate & Calibrate GENESYS Model Select Threshold(s) in GENESYS that define bad events Region wants to avoid Select Sustained Peaking Period for Capacity Metric (i.e. Planning Reserve Margin) Agree how to count resources toward satisfying Capacity Adequacy Standard –HYDRO –WIND –THERMAL –CONTRACTS Underway Done Underway

November 27, 2007 PNW Resource Adequacy Technical Committee Meeting4

November 27, 2007 PNW Resource Adequacy Technical Committee Meeting5 Historical vs. Calculated Calculated Sustained FCRPS Cap Purchases Cap to meet Expected Load Surplus + Cap to meet PRM

November 27, 2007 PNW Resource Adequacy Technical Committee Meeting6 Alignment with LOLP = 5% Approach: –Plan hydro capacity to assure sufficient capacity available to meet load 95% of time. –Plan hydro capacity to meet load under 1 in 20 probability event Adverse hydro Adverse temperature-induced load Select regional summer and winter hydro condition –For WECC and Resource Adequacy Forum reporting, the selection of hydro condition for which to report hydro capacity assures consistency –Utilities could then define temperature-induced adverse load conditions for their own resource planning efforts which approximate 1 in 20 probability event

November 27, 2007 PNW Resource Adequacy Technical Committee Meeting7 Representative NW Hydro Projects ROSS Round Butte Columbia River Hydro

November 27, 2007 PNW Resource Adequacy Technical Committee Meeting8 Suggested Representative Projects FCRPS –FCRPS not very sensitive to Selection of Adverse Event Non-Columbia River Projects –PGE’s Round Butte Project on Deschutes River is representative of Williamettes –Seattle’s ROSS on Skagit River is a representative West-side project

November 27, 2007 PNW Resource Adequacy Technical Committee Meeting9 Selecting Adverse Hydro Condition for Winter Event Approach –Look at candidate events, which represent more or less adverse hydro conditions –Investigate events with February flows within 1 standard deviation (α) lower than mean –Pick event which Region believes is most reasonable Candidate Feb Events – = reference, not candidate event – = 1 standard deviation below mean for Williamettes & Westside; adverse for Columbia R. – = less adverse for Williamettes & Westside; 1 standard deviation for Columbia R. – = somewhat adverse for all

November 27, 2007 PNW Resource Adequacy Technical Committee Meeting10

November 27, 2007 PNW Resource Adequacy Technical Committee Meeting11

November 27, 2007 PNW Resource Adequacy Technical Committee Meeting12 Next Steps Agree on Approach for evaluating regional hydro capacity both in summer & winter If hydro capacity is to be evaluated for single historical summer & winter event, agree on candidate events to be evaluated (still need research on summer events) FCRPS to be evaluated by BPA in-house Options for evaluating non-Federal Hydro Capacity –Each hydro utility to evaluate –Hire consultant to evaluate, or assist with evaluation through Technical Committee Subgroup –Possible consultants: Columbia Vista Vendor Other Consultant