1. Energy-Water-Climate Change Scenario Byron Woertz, Senior Project Manager W ESTERN E LECTRICITY C OORDINATING C OUNCIL

2. Changes Since Last Revision Consistent references to 1960-1979 as reference point for temperature change Minor textual changes Additional references to potential impacts of climate change (generator performance, possible spread of pathogens, population migration) References to geographical differences in climate change impacts Reference to possible impacts of increased lightning strikes Additional references to implementation of newer technologies (microgrids, optimized DR) Removal of references to implied connections between economic growth/policies and climate change Added potential impacts on reliability standards Tables and references moved to appendices 2 W ESTERN E LECTRICITY C OORDINATING C OUNCIL

3. Potential Textual Changes IssueOption 1Option 2 Narrative reference to GHG accumulations policies are put in place to slow their use. By 2034 it is clear that efforts to constrain fossil fuel use are not at levels sufficient to slow atmospheric greenhouse gas (GHG) accumulations primarily due to global economic expansion, continued population growth and the desire to sustain the rise of middle class lifestyles in developing countries. Omit the sentence Impacts of economic and technological development Despite these changes, economic development and a variety of technological drivers have not reversed the long-term trend toward a higher average global temperature. Delete the sentence. Early IndicatorsLeave discussion of Early Indicators as isDelete Early Indicators 3 W ESTERN E LECTRICITY C OORDINATING C OUNCIL

4. Next Steps 4 W ESTERN E LECTRICITY C OORDINATING C OUNCIL Create Scenario Assess System Impacts Create Study Cases Evaluate Potential Reliability Risks Consider Possible Risk Mitigations

5. Next Steps 5 W ESTERN E LECTRICITY C OORDINATING C OUNCIL Create ScenarioAssess System Impacts Impacts of climate change on the electrical system Quantify impacts Regional impacts of temperature rise Rainfall and amount and timing of runoff Impacts on demand Impacts on hydro Create Study Cases Evaluate Potential Reliability Risks Consider Possible Risk Mitigations

6. Next Steps 6 W ESTERN E LECTRICITY C OORDINATING C OUNCIL Create ScenarioAssess System ImpactsCreate Study Cases How can WECC model impacts with existing tools? What changes might be needed to the transmission system? Goal: understand needed grid modernization Evaluate Potential Reliability Risks Consider Possible Risk Mitigations

7. Next Steps 7 W ESTERN E LECTRICITY C OORDINATING C OUNCIL Create ScenarioAssess System ImpactsCreate Study Cases Evaluate Potential Reliability Risks Do any of the system impacts present potential reliability risks? Some impacts, if not addressed, could pose risks to reliability Other impacts may be negligible Consider Possible Risk Mitigations

8. Next Steps 8 W ESTERN E LECTRICITY C OORDINATING C OUNCIL Create ScenarioAssess System ImpactsCreate Study Cases Evaluate Potential Reliability Risks Consider Possible Risk Mitigations What actions could mitigate potential risks? Which actions would be the responsibility of WECC vs. other organizations?

9. Action Item “The Scenario Planning Steering Group approves the report titled ‘WECC Energy-Water-Climate Change Scenario,’ as amended during the May 5, 2015 meeting, and recommends proceeding with the additional actions for completing the work that are described in Figure 2 and associated narrative of the report ‘WECC Approach to Evaluating Reliability Risks Related to Climate Change.’” 9 W ESTERN E LECTRICITY C OORDINATING C OUNCIL

10. Questions Byron Woertz bwoertz@wecc.biz (801) 883-6841 10 W ESTERN E LECTRICITY C OORDINATING C OUNCIL