Evaluation of Columbia River Sustained Hydro Peaking Capacity Eric King / Mary Johannis PNW Resource Adequacy Technical Committee Meeting May 31, 2006 PNGC Offices, Portland, OR

May 31, 2006PNW Resource Adequacy Technical Committee Mtg 2 Steering Committee Adopted Form of Capacity Metric and Target Metric = Planning Reserve Margin Using 1 in 2 Loads Contingencies such as cold snap loads reflected in reserve margin 5-7% Contingency Reserve x % Outage Uncertainty y % Adverse Load & Load Forecast Uncertainty

May 31, 2006PNW Resource Adequacy Technical Committee Mtg 3 Comparison of FCRPS Capacities FCRPS Installed Hydro Cap= 21,500 MW 1 Hour Sustained Hydro Cap= 17,200 MW 10 Hour Over 5 Days Sustained Hydro Cap= 15,600 MW Sustainable Operational Cap= 11,200 MW Sustained Hydro Peaking Capacities White Book

May 31, 2006PNW Resource Adequacy Technical Committee Mtg 4

May 31, 2006PNW Resource Adequacy Technical Committee Mtg 5 Comparison of Reservoir Storages Operation to Meet Average Loads FCRPS Combined EOM Storage in Feb FCRPS Combined EOM Storage in Feb Operation to Meet Cold Snap Loads

May 31, 2006PNW Resource Adequacy Technical Committee Mtg 6 What Target Means to FCRPS FCRPS Cap to Meet 1 in 2 Load Planning Reserve Capacity No Resource Adequacy Acquisitions needed unless FCRPS cap to meet 1 in 2 loads + Planning Reserve is > 15,600 MW

May 31, 2006PNW Resource Adequacy Technical Committee Mtg 7 Pilot Study: Evaluation of Sustained Peak Hydro Capacity under a Worst Case Scenario

May 31, 2006PNW Resource Adequacy Technical Committee Mtg 8 Hydro Generation Results Capacity MWs (Hydro) 1 HR2 HR4 HR10 HR FCRPS17,23717,16317,10515,757 FCRPS & MID-Cs 21,45821,36221,29819,731

May 31, 2006PNW Resource Adequacy Technical Committee Mtg 9 We know that we have over MW of installed capacity, yet we are unable to generate this. Why, because: – We know we hold some capacity out for reserves –We have some turbines out for maintenance –Fore bay and tail water elevations all impact head, which impact capacity –water supply –Operating limitations –other impacts All the above impacts our instantaneous and sustained capacity.

May 31, 2006PNW Resource Adequacy Technical Committee Mtg 10 The system operated to full hydraulic extent (i.e. LIB, HGH, and DWR are operating to their full unit availability. GCL is allowed to draft up to 2 feet/day, the Snake and Lower Columbia projects operate with in their full normal operating range). NOTE: This constitutes a sustained draw down of the FCRPS. This type of analysis takes water from future periods, which will need to be accounted for later. For example, over the 5 day period: –Libby is drafted 5.5 feet; –HGH is drafted 3.5 feet, –DWR is drafted 7 feet; –and GCL is drafted 8 feet over and above what they normally would have been

May 31, 2006PNW Resource Adequacy Technical Committee Mtg 11 The system operated to full hydraulic extent (continued) LOWER SNAKE: The longer the sustained Peak – the lower the Peak MID-C: Rocky Reach and Rock Island – The 50 hour sustained Peak small lowering of their Peak Wanapum and Priest operate close to full all hours (with some spill) LOWER COLUMBIA: Operate close to full discharge