1. The Relationship between Greenhouse Gases and Hydroelectric Power Colleen Smith CHE379 Fall 2007

2. Hydroelectric Power Generation

3. Environmental Concerns of the 20 th Century

4. Environmental Concerns of the 21 st Century

5. Formation and Release of Biogas Anaerobic Digestion – Hydrolysis Bacteria splits protein – Acidification Requires/depletes Oxygen – Methanogenesis – Biogas formed Percolates upward out of reservoir surface – As the Methane rises it is oxidized into CO2 Rapid Release of methane at turbines – Pressure drop causes______

6. Affect of Biogas on the Environment Assume greenhouse gases, such as methane and carbon dioxide, cause global climate change

7. Affect of Global Warming on Precipitation

8. Affect of Global Warming on Snowpack Decreased snowpack means that more precipitation is turning directly into runoff and adding to streamflow in the winter months High flows in winter leave less snow to melt and provide water in the summer

9. Affect of Global Warming on Snowmelt Average time of Snowmelt is in Warmer weather causes earlier snowmelt Snowmelt time directly affects streamflow throughout the year

10. Affect of Snowmelt on Streamflow Increased March streamflow Decreased June streamflow

11. Affect of these changes on the Grand Coulee Dam General Hydroelectric Dam constraints – Prevent downstream flooding – Provide water during dry months – Generate electricity when releasing water Increased precipitation, less snowpack, and earlier snowmelt increases chance of flooding Less snowpack and earlier snowmelt decreases water availability during the summer Hydroelectric power generation is dependent upon flood hazard and water allocation needs

12. Modeling the Grand Coulee Dam HEC-HMS The 24hr 2yr and 100yr storm In 2000 and 2050 Turbine generators and spillway

13. Affect on The Grand Coulee Dam In all cases, water flowed over the spillway The greatest effect was seen in the 2yr storm event Without additional downstream dams, there would be disastrous flooding More additional water means greater potential for hydroelectric generation – If more turbines were installed

14. Conclusions Dams produce GHGs – CH4 and CO2 There is still debate regarding the scale and extent of the emissions – On a case by case basis There are small scale measures that could help – Vegetation Removal Underwater logging – Capture of CH4 – Ignore methane problems – Do nothing Global Warming affects the climate – Increased Precipitation – Decreased Snowmelt – Earlier Snowmelt – Earlier streamflow Possible flooding Could be harnessed with increased hydroelectric generation – More turbines

15. Questions?