1. California Energy Commission Drought Impacts on Electricity Generation Joint Workshop on California’s Drought Response Sylvia Bender, Deputy Director Energy Assessments Division August 28, 2015 Sylvia.Bender@energy.ca.gov/916-653-6841

2. California Energy Commission Topics to be Covered Monitoring and tracking drought impacts from water curtailments and loss of water supplies –Hydroelectric generation –100 thermal power plants On track to reduce water consumption and increase efficiency of thermal plants

3. California Energy Commission Hydroelectric Generation Declining as Portion of In-State Generation

4. California Energy Commission Thermal Generation and Water Issues Thermal power plants require some amount of water, even dry cooled units Monitor thermal generation vulnerabilities to water supply shortages during drought Tracking 30,000 MW out of California’s 78,000 installed generation capacity – 100 plants> 75 MW –Energy Commission jurisdictional plants (78) and most large natural gas-fired base load plants Surface water curtailments and dropping groundwater levels can impact plants

5. California Energy Commission

6. California Power Plants Depend on a Diversity of Water Sources Among these 100 plants being tracked: –Surface water use spread across 17 water districts, no one more than 8% of total –Groundwater spread across 13 groundwater basins Only 2 thermal plants in a subsidence basin –Recycled water considered most drought resistant supply

7. California Energy Commission Recycled Water Serves the Largest Portion of Tracked Plants

8. California Energy Commission Largest Share of Generation Capacity Being Tracked uses Recycled Water

9. California Energy Commission Recycled Water is Largest Share of Water Supply at Tracked Plants

10. California Energy Commission Thermal Power Plants on Track to Reduce Water Consumption /Increase Efficiency Energy Commission 2003 Water Policy Increase use of recycled water and dry cooling –85% of new 9,000 MW combined cycle projects built since then rely on recycled water or dry cooling Thermal efficiency increasing each year over last decade Greater use of dry cooled and recycled water plants could achieve additional potable water savings Further analysis of water use intensity at power plants underway