Renewable Energy II. Hydroelectric power systems

Transcription

1 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

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16 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

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

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24 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

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26 Tidal barrage systems Loire estuary, France

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28 Wave power experimental systems to date

29 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.

30 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.

31 Ground (c) and groundwater (b) geothermal.

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

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

34 100 meters North UTM Northing NAD 83 Craine Lake Bathymetric Map Depth Contours in Meters Catie Carr 8/27/08 UTM Easting NAD 83

35 Temperature August, meters North <10 o C UTM Northing NAD o C o C Craine Lake Summer Temperatures UTM Easting NAD 83

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

37 Temperature Range o C Volume of water 438,000 m 3 118,000,000 gallons Cooling Capacity in BTU (based on 2 o C degree temp. difference) Not calculated o C <10 o C 59,800 m 3 15,000,000 gallons 12,200 m 3 3,000,000 3 x 10 8 BTU 500 cooling days at 6000 BTU/hr 6 x 10 7 BTU 100 cooling days at 6000 BTU/hr

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

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

40 Temperature Range <3.5 o C Volume of water 467,000 m 3 125,000,000 gallons Heating Capacity in BTU (based on 2 o C temperature difference) 3.2 x 10 9 BTU (23,000 heating days at 6000 BTU/hr) o C 43,000 m 3 11,000,000 gallons 2.8 x 10 8 BTU (12,000 heating days at 6000 BTU/hr)