Capacity Analysis in the Sixth Plan GRAC Meeting May 6, 2009

Capacity Standard Surplus Sustained Peaking Reserve Margin The sustained peak generating capability of firm (and some non-firm) resources should equal the sustained peak load plus a surplus derived from the LOLP analysis. The minimum threshold is derived from an analysis that yields a 5% loss-of-load probability for capacity events.

Capacity Standard Surplus Sustained Peaking Capability Peak Duration Load Averaged over the peak duration hours – 6 highest load hours/day over 3 consecutive weekdays Based on normal weather Includes net interregional firm contracts

Capacity Metric For illustration only Generation values in table are the 6 and 10 highest – assume highest generation placed into appropriate hours Pink hours are the six highest load hours Peak limited defined by difference between Max Gen and Peak Load hour Actual generation not necessarily the most generation that we really could have shaped into peak hours Rather, this is intended to show the impact of the different metrics with this particular generation profile

Capacity Metric Consideration of applying Peak Limit to something different than Max Gen during fish passage season Achieving Max Gen may have been possible, but it would have required emptying of LSN/LCOL ponds Illustration of the importance of energy-limited capacity Note large value of Peak Limit. Is this why NWPP perceived no problem

Capacity Standard Surplus Sustained Peaking Capability Resources – Averaged over the peak duration Uncommitted in-region IPP generation Winter – all available Summer – 1000 MW Hydroelectric – Critical year for winter and summer Wind – 5 percent of nameplate Out-of-region market supply Winter – 3000 MW Summer – Zero Hydro Flexibility Winter – 2000 MW

Estimating Sustained Hydro Capacity (6-hour duration) Illustrative Only

DRAFT – Under Review

DRAFT – Under Review