1. Study Results PC8-PC16 System Stress Tests
This slide deck contains results from the 2012 TEPPC Study Program related to the various stress tests performed on the 2022 Common Case. The results of the studies are shown along with an indicator to show the robustness of transmission in that area.

2. 10-Year Stress Test Results
Description and goal
Assumptions
Results

3. Study Description and Goal

4. Stress Test Cases – two concepts…
PC8-PC15 – Add 6,000 GWh Renewables
PC16 – RPS Off-Ramp

5. Summary “Examine the Robustness of the Power Grid”
Evaluate system’s ability to integrate and deliver added resources to load, subject to transmission constraints
“Stress” the system
Proxy for
High gas (makes RE more competitive)
High load (requires higher RPS and more RE)
CO2 Policy (less thermal, more RE)
Increase in RPS (more RE)
Studies are designed as indicators
Help us to understand how the system may behave under a variety of future conditions. This is robust planning.

6. Caveats No additional transmission added
Small addition of RE will not solely justify addition of large interregional project
Capital cost analysis will not be performed as it is outside the intent of the study

7. Study Assumptions

8. Stress Test: PC8-PC15 Resource Selection Process
Calculate ratios of renewables in TEPPC 2022 Common Case
Do not include existing resources
Do not include DG
IRP and LRS data
Apply ratio to future build-out of 6,000 GWh
Concept: past trends are best the representation of what could be added to each state
More recourses available than what is identified in WREZ
More granular information from CPUC/CAISO
Locate resources using WREZ
Extrapolation Method

9. Resources from CPUC scenario that were originally decremented for Common Case net-short are added
Solar GWh
Evaluated as one 6,000 GWh study. Resource split 50/50 in each Basin state.
Per CPUC
Geothermal GWh

10. Stress Test: PC16 Resource Removal Process
WECC Class
Explanation
Class 0
Existing
Class 1
Under active construction. Projected to be in-service within five years.
Class 2
Additions that were reported to have:
Regulatory approval (or in review)
Signed Interconnection agreement
Expected on-line date within seven years
Class 3
Meet NERC criteria for Future Planned or Future Other Resources but that do not meet Class 1 or 2
Class 4
Meet NERC criteria for Conceptual Resources
Remove
WECC LRS Data Collection Manual

12. Common Case Results Refresher

13. Selection based on → Implementation Indicators Construction Status
Financial Indicators
Implementation Indicators
Selection based on →
Regional Significance

14. Potential “area of concern”
High utilization can be explained or is expected

15. Flow: NW to BC
Flow: BC to NW

16. IPP generation

17. CA gas units are “most marginal.”
Common Trends 1
System seems to be fairly robust given the CCTA and Common Case starting point of system utilization. 3
Heavier utilization, not much congestion (i.e., the transmission system still permits economic transfer). 2
When more renewable energy is added to the system, gas appears to be the marginal resource in all studies (except Montana), given our current price assumptions.
CA gas units are “most marginal.”

18. California Stress Test
Assumptions
Transmission Results
Generation Impacts
Key Finding
Stress test had only minor impact on transmission utilization. Including additional generation in
CA reduces requirement for imports.
Robustness Indicator

21. Arizona Stress Test Assumptions Transmission Results
Generation Impacts
Key Finding
Increase in AZ to CA imports. Congestion on P29. More detailed analysis required.
Robustness Indicator

24. New Mexico Stress Test Assumptions Transmission Results
Generation Impacts
Key Finding
Increase in P22 (SW of 4-Corners) utilization, but not congested. Other paths are not heavily impacted.
Robustness Indicator

27. Wyoming Stress Test Assumptions Transmission Results
Generation Impacts
Key Finding
Some sensitivity observed – P29 and P36. Large change in RMPA to Basin flow.
Robustness Indicator

30. Montana Stress Test Assumptions Transmission Results
Generation Impacts
Key Finding
Robustness Indicator
P8 congested as a result. MT system is relatively isolated and is easily stressed.

33. Washington Stress Test
Assumptions
Transmission Results
Generation Impacts
Key Finding
Small impact.
Robustness Indicator

36. Very little congestion observed.
Oregon Stress Test
Assumptions
Transmission Results
Generation Impacts
Key Finding
Very little congestion observed.
Robustness Indicator

39. Increased utilization, but not much congestion.
Basin Stress Test
Assumptions
Transmission Results
Generation Impacts
Key Finding
Increased utilization, but not much congestion.
Robustness Indicator

42. RPS Off-Ramp Stress Test
Assumptions
Transmission Results
Generation Impacts
Key Finding
Decrease in congestion outweighs increase.
Side bar: Is it apparent that our system designed for “RPS compliance” is highly versatile and can accommodate more “local” generation?
Robustness Indicator

45. Quick Summary NA NA
Robustness Indicator NA NA

46. Questions or thoughts on this study?