Hydroelectrical Power Generation

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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
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Energy in the News
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Breast Shot Wheel
Breast shot wheel One type of traditional Water
wheel Water wheels source Of power for
the Industrial revolution
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Overshot Wheel
More efficient that breast shot Wheel. Some
mills using These wheels still in operation In
rural appalachia in 1950s Miller Mrs.
Aarendale
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Typical Hydroelectrical Station
Outflow water can be very cold. Why? (Grand
Canyon)
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Low Head Hydroelectrical Generators
Low head Propellor type Turbines Power Change
in Potential Energy per Unit time weight
Vertical drop/time Energy Powertime
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Microhydro Installation
Small stream with Hydroelectrical
generator Power for one family (Jim Keener)
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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
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Francis turbine
Turbine used for moderate Head hydroelectrical
power statiosn
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Water Flow in a Francis Turbine
Left relative to turbine blades Right true
water path
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High Head Hydro
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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
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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.
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Optimum Hydroelectric Turbine Type
Optimum water Wheel not Just a function Of head,
also Depends on Water flow rate
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Hydroelectrical Power Use by State
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States Producing Most Hydroelectricity
Why is there So much Variation in the Gallons of
water Per kilowatthour?
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Hydropower Output by Nation
Lure of Hydropower Big Dams Vs Rebar
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Itaipu Dam
Presently worlds 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
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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
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Three Gorges Area
Great beauty Many historic Sights Still
pressing Ahead on dam construction Gorge
length San Francisco To LA
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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