1. Power Supply Adequacy Assessment Model/Methodology Review Steering Subcommittee Meeting January 29, 2010

2. January 29, 2010Resource Adequacy Steering Committee 2 Outline Model Validation –Benchmarking Process –Sample Historical vs. Simulated Dispatch Methodology Review –Current Adequacy Metric: LOLP –The Problem with LOLP –LOLP Subcommittee Suggestions –Next Steps

3. January 29, 2010Resource Adequacy Steering Committee 3 Model Validation HYDSIM vs. actual monthly generation GENESYS vs. HYDSIM hydro generation output Hydro peaking calibration – Trapezoidal Model/HOSS/Capacity Survey Check random variable distributions –Water, wind, forced outage, load/temperature Simulated thermal dispatch vs. historical dispatch Simulated hydro dispatch vs. historical dispatch Simulated dispatch vs. scheduler’s perspective

4. January 29, 2010Resource Adequacy Steering Committee 4

5. January 29, 2010Resource Adequacy Steering Committee 5 Sample Comparison of Historical vs. Simulated Hydro Dispatch Hourly hydro dispatch is highly dependent on hourly load shape Historical and Genesys hydro load following is consistent Illustrative only – based on old data and F&W constraints

6. Methodology Review Current Adequacy Metric: LOLP

7. January 29, 2010Resource Adequacy Steering Committee 7 Cold Hydro Limited GENESYS SimulationIllustrative Example Only

8. January 29, 2010Resource Adequacy Steering Committee 8 Curtailment Events (Peaking problems and energy shortages) Each event has a peak and duration.

9. January 29, 2010Resource Adequacy Steering Committee 9 What do we Count? Ideally, we count “significant” events (those that we want to avoid) Energy threshold (or contingency resource) is 1,200 MW for one day or 28,800 MW- hours from Dec-Mar Capacity threshold (or contingency resource) is 3,000 MW in any hour from Dec-Mar and from Jun-Sep

10. January 29, 2010Resource Adequacy Steering Committee 10 Curtailment Events (non-events not shown)

11. January 29, 2010Resource Adequacy Steering Committee 11 Loss of Load Probability Simulated 300 winters (December through March) Out of 300 winters, 15 had an average curtailment greater than 10 MW-seasons, which means that the Winter Loss of Load Probability (LOLP) = 15/300 = 5 percent

12. January 29, 2010Resource Adequacy Steering Committee 12 Energy LOLP (Sum of Curtailed Energy Dec-Mar)

13. The Problem with LOLP

14. January 29, 2010Resource Adequacy Steering Committee 14 Potential Problem with LOLP Same LOLP – Bigger Magnitude

15. January 29, 2010Resource Adequacy Steering Committee 15 Potential Problem with LOLP Lower LOLP – Bigger Magnitude

16. LOLP Subcommittee Report and Recommendations

17. January 29, 2010Resource Adequacy Steering Committee 17 LOLP Subcommittee Report Clearly define all reserve requirements –Operating reserves –Planning reserves –Wind integration reserves Determine which reserve curtailments count toward LOLP Add temperature-correlated wind as a random variable Decouple temperature and water condition Define a “contingency” resource for each month of the year instead of defining threshold events Record curtailment events across all months of the year Consider using other adequacy metrics Continue to assess climate change impacts

18. January 29, 2010Resource Adequacy Steering Committee 18 LOLP Review Status Reserves –Work being done by PNUCC committee Temperature-correlated wind –BPA working on a test data set Decouple temp and water –Done Contingency resource –Work needs to be assigned Annual metric –Not yet started Other metrics –BPA draft methodology –PSRI review Climate change –Ongoing

19. Next Steps

20. January 29, 2010Resource Adequacy Steering Committee 20 Possible Modifications to the Current Method Replace LOLP with an alternative metric Use LOLP in conjunction with an alternative adequacy metric Use LOLP in conjunction with the magnitude of the most severe event (or an average of the worst 10% of events)

21. January 29, 2010Resource Adequacy Steering Committee 21 Examples of Other Adequacy Metrics LOLE: loss of load expectation (%) –Number of hours with curtailment divided by the total number of hours simulated –Can be more intuitive, i.e. 99.5% reliable –Does not address magnitude EUE: expected unserved energy (MW-hr) –Average amount of unserved energy per year –Lacks specific information about severe events

22. January 29, 2010Resource Adequacy Steering Committee 22 Work Plan PSRI review complete by early 2010 Benchmark GENESYS by early 2010 Tech Committee propose new metric and threshold by April of 2010 Use new metric to assess 3 and 5 year adequacy by June 2010