1. Study Results Wyoming Firmed Resource Option This slide deck contains results from the 2012 TEPPC Study Program related to the Wyoming Firmed Resource Option studies. The generation results for the associated transmission expansion projects follow immediately after, along with flow information for the added transmission.

2. Gas Firming Modeling Goal Allow incremental gas CT’s (located in WY) to dispatch based on economics. Using a nomogram, force their output down DC lines (with wind). Implementation Steps Start with 2022 PC21 Wyoming Resource Option (+12,000 GWh) 1.Add 1,000 MW of incremental gas CC’s physically located in WY Economic dispatch based on where DC line terminates Standard “CC Recent” modeling 2.Remove CT’s no longer needed for PRM PRM may have been supplemented by added CC’s Remove CT’s from region where DC line terminates Essentially assume DC line assures delivery 4.Use nomogram to force both wind and CC dispatch down DC line DC Line Flow ≥ Added Wind + Added CTs

3. Add: 12,000 GWh to meet WECC RPS Add transmission Renewable Options Under High Load Firmed Cases Increase WECC-wide load 8% 1 2 4 For these regions 3 Add: firming resource Gas Hydro Pumped storage

4. Increase WECC-wide load 8% 1 8% 8% increase to peak and energy 10% 10% decrease to energy Higher Load = Additional RPS Energy

5. Calculate ratios of planned renewables in TEPPC 2022 Common Case Do not include existing resources Did not include DG IRP and LRS data Apply ratio to study build-out of 12,000 GWh Concept: development trends are best representation of what could be added to each state More resources available than what is identified in WREZ More granular information from CPUC/CAISO Locate resources using WREZ peer-analysis tool Extrapolation Method Add 12,000 GWh to meet WECC RPS 2

6. 10-Year Study Results Wyoming Firmed Resource Option Studies EC26-1 TransWest Express EC26-2 Zephyr A EC26-3 Zephyr B EC26-4 Zephyr C EC26-5 Zephyr D Zephyr A Zephyr B Zephyr C TransWest Express Zephyr D

7. Production cost decreased $21 M (.1%) Dump energy increased 9.6 GWh (2.6%) Emergency Energy decreased.4% CO2 Emissions decreased.1% AZ, NV, CA, CO

8. Production cost decreased $426 M (2.4%) Dump energy increased 54.1 GWh (16.2%) Emergency Energy decreased.6% CO2 Emissions decreased 1.3% NV, CA, CO

9. What is different? Loads Transmission Resources

10. What is different? Loads Transmission Resources

14. 10-Year Study Results Wyoming Firmed Resource Option Studies EC26-1 TransWest Express EC26-2 Zephyr A EC26-3 Zephyr B EC26-4 Zephyr C EC26-5 Zephyr D Zephyr A Zephyr B Zephyr C TransWest Express Zephyr D

15. Production cost decreased $160 M (.9%) Dump energy increased 121GWh (33%) Emergency Energy decreased.6% CO2 Emissions decreased 0% WY

16. Production cost decreased $244M (1.4%) Dump energy increased 153 GWh (46.2%) Emergency Energy increased.4% CO2 Emissions decreased 1.4% AZ, NV, CA, WA WY

17. What is different? Loads Transmission Resources

18. What is different? Loads Transmission Resources

22. 10-Year Study Results Wyoming Firmed Resource Option Studies EC26-1 TransWest Express EC26-2 Zephyr A EC26-3 Zephyr B EC26-4 Zephyr C EC26-5 Zephyr D Zephyr A Zephyr B Zephyr C TransWest Express Zephyr D

23. Production cost decreased $150M (2.4%) Dump energy increased 138 GWh (38%) Emergency Energy increased.4% CO2 Emissions decreased.1% AZ, NV, CA WY

24. Production cost decreased $254M (1.4%) Dump energy increased 170 GWh (51%) Emergency Energy decreased.1% CO2 Emissions decreased 1.3% AZ, NV, CA, WA WY

25. What is different? Loads Transmission Resources

26. What is different? Loads Transmission Resources

30. 10-Year Study Results Wyoming Firmed Resource Option Studies EC26-1 TransWest Express EC26-2 Zephyr A EC26-3 Zephyr B EC26-4 Zephyr C EC26-5 Zephyr D Zephyr A Zephyr B Zephyr C TransWest Express Zephyr D

31. Production cost decreased $118 M (.7%) Dump energy increased 124 GWh (34%) Emergency Energy decreased 0% CO2 Emissions decreased 0% AZ, NV, CA, WA WY

32. Production cost decreased $286M (1.6%) Dump energy increased 156 GWh (47%) Emergency Energy decreased.2% CO2 Emissions decreased 1.3% AZ, NV, CA, WA WY

33. What is different? Loads Transmission Resources

34. What is different? Loads Transmission Resources

38. 10-Year Study Results Wyoming Firmed Resource Option Studies EC26-1 TransWest Express EC26-2 Zephyr A EC26-3 Zephyr B EC26-4 Zephyr C EC26-5 Zephyr D Zephyr A Zephyr B Zephyr C TransWest Express Zephyr D

39. Production cost decreased $472M (2.7%) Dump energy increased 78 GWh (21%) Emergency Energy increased.9% CO2 Emissions decreased 1.6% WY

40. Production cost decreased $68M (.3%) Dump energy increased 110GWh (33%) Emergency Energy increased.7% CO2 Emissions decreased 3% WY

41. What is different? Loads Transmission Resources

42. What is different? Loads Transmission Resources

46. Questions or thoughts on this study?