1. Study Results High Hydro Study Low Hydro Study This slide deck contains results from the 2011 TEPPC Study Program. This study shows the impacts of low and high hydro conditions on generation, transmission, and production cost.

2. 2 Central Question: How does production cost, generation dispatch, and transmission utilization change under low hydro conditions? Change to starting input assumptions: o Loads – none o Transmission System – None o Generation – 2011 hydro data substituted for median hydro data (2005) Results follow… 2022 PC1-1 High Hydro Sensitivity

3. 3 2022 High Hydro Results – Changes in Total Annual Generation GWh

4. 4 2022 High Hydro Results – Changes in Generation by State

5. 5 2022 High Hydro Results – Changes in Region-Region Transfers

6. 6 2022 High Hydro Results – Changes in Transmission Utilization P45 SDG&E-CFE P29 Intermountain-Gonder P26 Northern- Southern California P03 Northwest-British Columbia P47 – Southern New Mexico Most Heavily Utilized Paths Increases in U90 Relative to Common >5% Case Indicated in Red P08 Montana to Northwest P60 Inyo-Control P27 IPP DC Line P11 West of Crossover P10 West of Colstrip P01 Alberta-British Columbia P65 PDCI *NEW* P66 COI *NEW* P16 Idaho-Sierra *NEW*

7. 7 Central Question: How does production cost, generation dispatch, and transmission utilization change under low hydro conditions? Change to starting input assumptions: o Loads – none o Transmission System – None o Generation – 2001 hydro data substituted for median hydro data (2005) Results follow… 2022 PC1-2 Low Hydro Sensitivity

8. Selection of Low Hydro Year Single coincident year selected, except for BC –Modeled data for a dry year provided by BC Hydro Year selection based on overall WECC-wide low hydro conditions

9. 9 2022 Low Hydro Results – Changes in Total Annual Generation GWh (MWh)

10. 10 2022 Low Hydro Results – Changes in Generation by State

11. 11 2022 Low Hydro Results – Changes in Region-Region Transfers

12. 12 2022 Low Hydro Results – Changes in Transmission Utilization P45 SDG&E-CFE P29 Intermountain-Gonder P26 Northern- Southern California P03 Northwest-British Columbia P47 – Southern New Mexico Most Heavily Utilized Paths Increases in U90 Relative to Common >5% Case Indicated in Red P08 Montana to Northwest P60 Inyo-Control P27 IPP DC Line P11 West of Crossover P10 West of Colstrip P01 Alberta-British Columbia

13. Questions or thoughts on this study?