Renewable Energy II Hydroelectric power systems high initial investment, low operating cost, long life expectancy no emissions; high capacity, reliability reservoirs provide water storage for navigation, irrigation, water supply flood control, controlled discharge for recreation, fishing reservoirs flood valuable land; displacement of towns; cultural history reservoirs may increase evaporation and salinity of water water quality may decline due to impoundment natural fluctuations in stream flow are reduced – flooding reduced, but... temperature regimes are disrupted – cold water released sediment starvation of downstream system Colorado River – Lake Powell, Lake Mead Yangtze River – Three Gorges Dam Nile River – Aswan High Dam

Aswan High Dam Completed in 1970 Significant flood control and irrigation advantages Floodplains downstream starved of new sediment input. Delta subsidence and erosion Salinity Destruction and damage to cultural sites

Three Gorges Dam Yangtze River Hydropower to offset new coal-fired plants, flood control Ecosystem impacts, water quality concerns social displacement Earthquakes?

Tidal and Wave Power Tidal systems generally require a control dam (‘barrage’) to direct flow through turbines. Some tidal systems have sufficient velocity to drive turbines without impoundment Wave systems - experimental; disappointing to date Geothermal Steam and hot water Hot dry rock – injection and recovery of steam or hot water has been problematic Ground, groundwater and lake geothermal – heat pump system Depend on low-temperature (66-39 F heat exchange provide air conditioning Closed loop systems preferred

Tidal barrage systems – Loire estuary, France

Wave power – experimental systems to date

“Hot’ geothermal systems currently in operation depend on natural recharge of cool surface water which is heated by hot rock or magma in areas of volcanic activity.

Hot dry rock systems require injection of cool surface water and production of steam or hot water from fractured rock at depth. These systems have not been successfully developed to date. Loss of water to dry rock, and possible triggering of earthquakes are ongoing problems.

Ground (c) and groundwater (b) geothermal.

Lake or pond geothermal. Water at bottom of lake does not cool below 4C (39F). Heat pump required for residential heating.

Craine Lake - a 22 acre private lake about 5 miles south of Hamilton. Geothermal potential for 36 residences around the lake??

Craine Lake Bathymetric Map Depth Contours in Meters Catie Carr – 8/27/ meters North UTM Northing NAD 83 UTM Easting NAD 83

22-25 o C o C <10 o C 100 meters North Craine Lake Summer Temperatures UTM Northing NAD 83 UTM Easting NAD 83 Temperature August, 2008

10 meters 5 meters Lake surface summer bottom water <10 o C summer surface layer o C thermocline layer Summer thermal structure

Temperature Range Volume of water Cooling Capacity in BTU (based on 2 o C degree temp. difference) o C438,000 m 3 118,000,000 gallons Not calculated o C59,800 m 3 15,000,000 gallons 3 x 10 8 BTU 500 cooling days at 6000 BTU/hr <10 o C12,200 m 3 3,000,000 6 x 10 7 BTU 100 cooling days at 6000 BTU/hr

<3.5 o C o C 100 meters North UTM Northing NAD 83 UTM Easting NAD 83 Temperature February, 2009

10 meters 5 meters Lake surface slightly warmer bottom water <3.5 – 4.0 C cold surface layer less than 3.5oC Winter thermal structure

Temperature Range Volume of water Heating Capacity in BTU (based on 2 o C temperature difference) <3.5 o C467,000 m 3 125,000,000 gallons 3.2 x 10 9 BTU (23,000 heating days at 6000 BTU/hr) o C43,000 m 3 11,000,000 gallons 2.8 x 10 8 BTU (12,000 heating days at 6000 BTU/hr)