Long-term Strategies for Energy Utilities WSWC – WGA Water/Energy Workshop April 2, 2013

2 Water/Energy Nexus – Colorado Context Self-supplied Industry  Thermoelectric generation (~ 50%)  Snowmaking  Sand/Gravel  Other large industry Source: Colorado Water Conservation Board, Statewide Water Supply Initiative, Denver Water 90% Agriculture 8% Municipal Self-supplied Industry % 82% Agriculture 15% Municipal Self- Supplied Industry % Avg. residential electric demand – 9.3 gallons per day, <6% Denver Water daily per capita water use in 2011.

3 Water Supply Strategy Supply Diversity  Direct-flow/Storage  Self-supplied/contract supply  Native basin/trans-basin  Recycled wastewater Supply Integration/Flexibility Engagement

4 Drought Resilience thru Cooperative Agreements Municipal Agreements  Contract supplies  Trades  “Unique” arrangements Agriculture Agreements  Interruptible Supply  Recharge Credits

5 DENVER LONGMONT GREELEY STERLING South Platte Poudre St. Vrain Clear Creek Northern Water Denver Water Contract Ag GLENWOOD SPRINGS Ag Hydro Storage

6 Water Stewardship Plant process improvement and reuse opportunities  Process wastewater for lime scrubbing  Process wastewater for bottom ash removal  Increased cooling tower cycles Technology  Combined-cycle gas generation  Hybrid cooling  Recycled wastewater  Renewables  Demand-side management

7 Water Usage at PSCo Generating Stations

8 Future Trends and Water Use Impacts Gas and combined cycle generation Renewables Emission controls Carbon capture