1. Defining LOLP Resource Adequacy Forum Technical Subcommittee Meeting November 14, 2008

2. November 14, 2008Resource Adequacy Technical Committee 2 Outline Correlation among random variables Different ways to calculate LOLP Redefining LOLP for the NW Comparison to other regions

3. November 14, 2008Resource Adequacy Technical Committee 3 Correlating Uncertainties in Genesys Demand and temperature Wind and temperature Thermal forced outage - independent Water supply - independent

4. November 14, 2008Resource Adequacy Technical Committee 4 No Correlation between Water Supply and Temperature Monthly average natural flow at The Dalles vs. monthly average regionally weighted daily temperature

5. November 14, 2008Resource Adequacy Technical Committee 5 Curtailment Events for a Study

6. November 14, 2008Resource Adequacy Technical Committee 6 Study Statistics Number of Simulations (Games)50 Hours in the Dec-Mar period2,904 Total number of hours simulated145,200 Number of games with at least one hour of curtailment18 Number of curtailment hours (over all games)275 Number of curtailment events83 Average magnitude per event1,953 MW-hrs Average duration per event3.4 hours Average number of events per game with curtailments4.6

7. November 14, 2008Resource Adequacy Technical Committee 7 What’s the LOLP? Types of events No. of Games LOLP (%) At least 1 hour of curtailment1836 Total curtailment > 28,800 mw-hrs24 Total curtailment > 10,000 mw-hrs612 At least one event > 4 hours1326 At least one event > 4,000 mw-hrs918 At least one event > 4-hour & > 4,000 mw-hrs510 At least five hours with curtailment > 1,000 mw510 At least ten hours with curtailment > 1,000 mw24 At least one hour with curtailment > 1,000 mw1122

8. November 14, 2008Resource Adequacy Technical Committee 8 LOLP vs. Energy Threshold 28,800 MW-Hrs LOLP = 4% 10,000 MW-Hrs LOLP = 12%

9. November 14, 2008Resource Adequacy Technical Committee 9 Redefining LOLP Include an “emergency” resource instead of an energy or capacity threshold Include magnitude of problem in the calculation Define a single value to cover energy and capacity needs year round LOLP subcommittee is working on this

10. November 14, 2008Resource Adequacy Technical Committee 10 Comparison to other Regions Different random variables Different definitions for LOLP Different assumptions about “emergency” resources Different requirements, i.e. annual needs and sustained peaking needs versus single hour needs BPA is working on this