2020 Study Cases

1. 2020 Study Cases WECC Staff SWG Conference Call November 18, 2010

2. Outline Changes applied to 2020 PC0 after dataset was posted Summary of results from revised 2020 PC0 dataset Timeline/Tasks for completing the remaining 2020 study cases

3. Changes Applied to 2020 PC0 After Posting the Dataset • Modeling of the OTC Replacement Units • Based on decisions made by TAS on Nov 8 • Modeling of the IPP DC Line • Nomogram added to equate flow on the DC line to output of LA-owned generation in UT • Additional gap generator added in Alberta • Further decreased emergency energy in Alberta

4. Changes to OTC Units • Summary of changes made: • Generic OTC CCs and CTs in SCE were reduced by 2,330 MW to reach a 17% planning reserve margin in CA-South • The OTC CCs and CTs were reduced by an equivalent amount to keep the split of OTC replacement units 50% CC and 50% CT • The heat rate of the generic OTC CCs was set to 8.5 MMBtu/MWh to reduce operation in response to air quality issues

5. CA-South Planning Reserve Margin Before changes: After changes:

6. Comparison of Average Capacity Factor and CO2 Emissions Comparison done for OTC replacement units only The capacity factor of the SCE OTC replacement CC units was reduced due to the increase in the heat rate of the generic OTC CCs Increases in the capacity factor of the other CA OTC replacement units is due to the removal of the generic OTC CCs in SCE

7. Change in Annual Generation Combined cycle units in Arizona, Nevada, Utah, and the Northwest increased in response to the reduction of CC generation in CA-South

8. Change in Region-to-Region Transfers Increased transfers into CA-South are the result of the generation shift observed on the previous slide

9. Change in Path Flows

10. Change in Path Flows

11. Change in Path Flows Positive Direction: S to N

12. Change in Path Flows

13. Change in Path Flows

14. DC Line Modeling in PROMOD • PROMOD does not take into account that losses may be reduced if generation is transmitted via DC and not AC lines • Test runs indicate that PROMOD uses DC lines more for congestion management, loading the nearby AC lines first • PROMOD may be unfairly penalizing the DC lines, resulting in lower than expected line utilization

15. DC Line Modeling in PROMOD • Modeling questions: • How are DC lines dispatched in reality? • How are future DC lines expected to be dispatched? • Ways to “game” the model: • Create a nomogram to tie output of generation to flow on a DC line • Reduce/eliminate losses modeled on a DC line • Do we want to pre-determine the dispatch of the DC lines in PROMOD?

16. Modeling the IPP DC Line • The IPP DC line is used to transfer generation located in Utah to entities that own the generation in southern CA • To better model how this line is used in reality, Staff created a nomogram linking the flow on the DC line to the output of CA-owned generation in Utah • Generators included: Intermountain 1&2, Milford Wind 1&2, Hatch Geothermal

17. Modeling the IPP DC Line

18. Revised 2020 PC0 – Annual Generation Summary “Other”

19. Renewable Resources Modeled in 2019 vs. 2020 Base Case 2019 Renewables: 159,180 GWh, 15% of total generation 2020 Renewables: 172,345 GWh, 16.8% of total generation

20. Renewable Resources Modeled in 2019 vs. 2020 Base Case

21. California Renewable Resources

22. Top 10 Most Congested Paths U99 = % time flow is greater than 99% of the path rating Indicates direction of primary congestion

23. Path Duration Plots

24. + E to W + S to N

25. + E to W + E to W

26. + N to S + N to S

27. + S to N + E to W

28. + E to W + E to W

29. + N to S + NE to SW

30. + N to S + N to S

31. + N to S + NE to SW

32. Timeline/Tasks for Completing the Remaining 2020 Studies

33. TEPPC Base Case/SPSC Reference Case • Base Case is complete • Reference Case • DSM is being finalized • Load/Resource Check • Remove conventional resources?

34. Remaining SPSC Study Cases • Tasks in progress- • Modifying the renewable resources • Does this make sense for the high load case, and high DSM case? • Load/resource balance check • Does it make sense to add/remove conventional resources depending on the study case (high load, high DSM)

35. Modifying the Renewable Resources for the SPSC Study Cases • High DSM Case- • Reductions were taken from the “gap” renewables used to meet RPS in the base/reference cases for AZ, CO, NM, MT • Non-descript wind resources were reduced in WY and WA, where no “gap” resources were available • CA reductions were made based on Keith White’s specifications, but 2,413,283 MWh of additional reductions are still required

36. Modifying the Renewable Resources for the SPSC Study Cases • High DSM Case, continued – • Nevada had excess renewables in the TEPPC base case, and in the SPSC reference case • This excess was previously applied to the CA RPS target (excess ~600 GWh) • In the High DSM Case NV has an excess of 1,497 GWh • Should we now consider reducing the NV renewables? Remove the LRS class 2&3 renewables not identified in the IRPs?

37. Aggressive Wind Scenarios • What resources will we be removing? • How will we decide where to add the incremental resources? • Will we be making any other changes to the generation portfolio? • i.e. Should we replace the lost renewable capacity value in CA-South with additional conventional generation? Similarly, would we then remove conventional generation in MT/WY based on the capacity value of the added wind?

38. Questions?