Hydroelectrical Power Generation Traditional Methods of Hydroelectric Generation
- Slides: 21
Hydroelectrical Power Generation Traditional Methods of Hydroelectric Generation Low Head Power Generation Medium Head Power Generation High Head Power Generation Large Dams (Three Gorges, Itaipu) Environmental Effects of Large Dams
Energy in the News
Breast Shot Wheel Breast shot wheel: One type of traditional Water wheels: source Of power for the Industrial revolution
Overshot Wheel More efficient that breast shot Wheel. Some mills using These wheels still in operation In rural appalachia in 1950’s Miller: Mrs. Aarendale
Typical Hydroelectrical Station Outflow water: can be very cold. Why? (Grand Canyon)
Low Head Hydroelectrical Generators Low head: Propellor type Turbines Power = Change in Potential Energy per Unit time = weight* Vertical drop/time Energy = Power*time
Microhydro Installation Small stream with Hydroelectrical generator: Power for one family (Jim Keener)
Moderate Head Hydro Head: height difference Between water level in Reservoir and water Level entering turbine Head= height in potential Energy equation Penstock: tube water flows Through
Francis turbine Turbine used for moderate Head hydroelectrical power statiosn
Water Flow in a Francis Turbine Left: relative to turbine blades Right: true water path
High Head Hydro
Pelton Water Wheel Used for high head applications: (above 250 meters) Are impulse turbines. Francis and Propeller type turbine Are reaction turbines. Reaction turbines: run submerged. Impulse turbines: run in normal air
Jets of Water Hitting Pelton Wheel Jets of water are directed through a nozzle onto Pelton wheel Cups on the wheel transfer kinetic energy from water to wheel.
Optimum Hydroelectric Turbine Type Optimum water Wheel: not Just a function Of head, also Depends on Water flow rate
Hydroelectrical Power Use by State
States Producing Most Hydroelectricity Why is there So much Variation in the Gallons of water Per kilowatthour?
Hydropower Output by Nation Lure of Hydropower Big Dams Vs Rebar
Itaipu Dam Presently world’s largest Hydroelectric plant On Parana river between Brazil and Paraguay Capacity: 12, 600 MW (drought a problem recently): Provides: 25% of Brazil power 78% of Paraguay power
Three Gorges Area of Yangtze River Under construction Three Gorges Dam in China Moving 1. 2 million People Capacity of 18, 600 MW Will finish in 2009
Three Gorges Area Great beauty Many historic Sights Still pressing Ahead on dam construction Gorge length; ~San Francisco To LA
Environmental Problems with Dams 1) Silt buildup fills reservoir (Yangtze; levees) 2) Fish migration disrupted (Columbia) 3)Water temperature decreases (Colorado) 4) Water gets more saline (Colorado) 5) Water loses oxygen (Brazil) 6) Water slows down, increases disease (mosquitos, schitosomiasis (Aswan)) 7) Water traps pollution, slows pollution flushing 8) Induced seismicity may occur