1. NORTHWEST POWER POOL Reliability Update – Summer 2010 April 2010 Jerry D. Rust

2. 2 NERC/WECC Sub-regions Northwest Power Pool Alberta Electric System Operator Avista Corporation Bonneville Power Administration British Columbia Transmission Corporation Chelan County PUD Douglas County PUD Grant County PUD Idaho Power Company NaturEner Glacier Wind Energy Northwestern Energy PacifiCorp-East PacifiCorp-West Portland General Electric Company Puget Sound Energy Sacramento Municipal Utility Board Seattle City Light Sierra Pacific Power Company Tacoma Power Turlock Irrigation District Western Area Power Administration – UGP CAMX AZNM RMPP NWPP Rocky Mountain Power Pool Public Service Company of Colorado Western Area Power Administration – CM Arizona-New Mexico Arizona Public Service Company CECD – Arlington Valley CECD – Griffith CECD – Harquahala CECD – Panda Gila River El Paso Electric Company Imperial Irrigation District Nevada Power Company CECD – Panda Gila River Public Service Company of New Mexico Salt River Project Tucson Electric Power Company Western Area Power Administration – LCD California-Mexico California Independent System Operator Comision Federal de Electicidad Los Angeles Dept. of Water and Power

3. 3 Reliability Update NWPP Coincidental Load 2010 Forecasted Summer Peak60,000 MW (50% probability of not being exceeded) 20 Balancing Authorities Operating Reserve Requirement ~ 4,200 MW

4. 4 Balancing Authority Load Largest to smallest by Entity Balancing Authority Load on Average NorthWestern Energy Seattle City Light Sierra Pacific Power Tacoma Power Grant PUD Chelan PUD Turlock Irrigation District Douglas PUD Western Area Power Administration Upper Great Plains NaturEner Glacier Wind Energy (generation only) Alberta Electric System Operator PacifiCorp (PACE & PACW) BC Transmission Corp Bonneville Transmission Puget Sound Energy Portland General Electric Idaho Power Sacramento Municipal Utility District Avista

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6. 6 Reliability Update Issues To Watch Precipitation – Below normal precipitation impacts the future energy availability and current day flexibility Runoff – Columbia River flows forecasted to be ~66% of the 30 year average, as compared to 2009 at 83%

7. 7 Reliability Update Wind Resources Installed in NWPP Area 6,500 MW Historic contribution to meet summer Peak – ZERO MW NERC Reliability Assessment Margin – 16% to 24% (No wind contribution) (Sustained hydro reduces availability by ~7,000 MW)

8. 8 Reliability Update ISSUES TO WATCH Economic Conditions – No economic recovery Extreme Weather Conditions – Summer - Every 1-degree above normal increases Peak Demand by 350-400 MW (maximum increase of 4,000 MW) which would result in a peak of 64,000 MW, with operating reserve, total requirement ~ 4,500 MW)

9. 9 Reliability Update Today’s Overall Expectation Resources are forecasted to be ~100% adequate to meet the anticipated load requirements, including reserve during the 2010 summer for the NWPP area.

10. QUESTIONS?