1. Interim and Long-term Approaches for Assessing Wind’s Contribution to Capacity Adequacy PNW Resource Adequacy Steering Committee Meeting July 21, 2008

2. PNW Resource Adequacy Steering Committee Meeting2 WIAP Action 1 - Wind Capacity Value Phase I: By July 2007, the Northwest Resource Adequacy Forum should reassess its 15 percent pilot sustained wind capacity value using currently available data on wind plant operation during periods of peak load. Phase II: In 2008, the NWRA Forum should further refine the sustained peaking capacity value of wind power using the improved wind resource data set of Action 3 and other available data.

3. July 21, 2008PNW Resource Adequacy Steering Committee Meeting3 PHASE I: Interim Wind Capacity Value Council 2011 and 2013 Resource Adequacy Assessments –Wind Capacity Contribution to Resource Adequacy equated to 5% installed capacity –Placeholder value –Supported by BPA’s wind capacity analyses in the BPA control area

4. July 21, 2008PNW Resource Adequacy Steering Committee Meeting4 PHASE II: Long-term Plan to develop Wind Capacity Value Need sufficient years of hourly wind generation by wind site for GENESYS to perform Monte Carlo picks Ideally would like backcast wind generation simulation to ascertain performance of wind over historical cold snaps/heat waves

5. July 21, 2008PNW Resource Adequacy Steering Committee Meeting5 LONG-TERM OPTIONS Synthetic Data Assumes recent years of wind generation are representative of long-term history Use statistics from actual data to create synthetic wind data Advantage = this data set can be created now Backcast Simulation Need clean Anemometer Data for several decades –Stable location, altitude, or way to adjust data –On-site data preferable Need good Correlations between anemometer data and actual wind generation –Consider wind speed, direction, lag time Allows analyses of historical cold snaps/heat waves

6. July 21, 2008PNW Resource Adequacy Steering Committee Meeting6 OPTION 1: Synthetic Data Investigate long-term anemometer data to test whether recent record of actual wind generation is typical of long-term record If so, use Synthetic Data If not, may still need to use Synthetic Data until credible Backcast Simulation is complete

7. July 21, 2008PNW Resource Adequacy Steering Committee Meeting7 OPTION 2: Backcast Simulation Results from BorisMetrics Contract provide starting point for more detailed analyses BorisMetrics Contract Purpose: −Evaluate Wind Generation that would have been available to meet peak loads during historical cold snaps/heat waves −Develop Backcast simulation of Hourly Wind Generation as input to the GENESYS Loss of Load Probability model

8. July 21, 2008PNW Resource Adequacy Steering Committee Meeting8 Borismetrics Work Identified Issues Most frequent capacity factor is 15% of nameplate rather than 0%, as shown by the BPA Wind Capacity Analyses Was Gorge windier in the past, or is there a problem with the simulation? Case of the missing zeros: −"dummy" or surrogate variables to allow for generation facilities to be shut down for maintenance or other reasons. −Problem identified: 40% of time when wind was blowing, there was zero wind generation. 1/ 1/ Probability of occurrence should be divided by 10

9. July 21, 2008PNW Resource Adequacy Steering Committee Meeting9 Borismetrics Work Identified Issues Case of missing zeros –Example: East Gorge Generation Dec 2006 –Why is there so little generation when the wind is blowing?

10. July 21, 2008PNW Resource Adequacy Steering Committee Meeting10 Borismetrics Work Identified Issues Can a unique function calculating generation based on wind speed be determined?

11. July 21, 2008PNW Resource Adequacy Steering Committee Meeting11 Borismetrics Work Identified Issues Pendleton Anemometer Data not Clean

12. July 21, 2008PNW Resource Adequacy Steering Committee Meeting12 Next Steps Form Technical Wind Assessment Team to: –Investigate seasonal/annual variability of wind to determine if Synthetic Data Option is workable –Investigate whether better Correlations are achievable using on-site wind anemometer data Check whether anemometer data is clean and of sufficient length If height of anemometer readings has varied; can adjustments be made to data? Is there sufficient anemometer and generation data to create credible backcast simulations?