hydroelectric combined

7/27/2019 Hydroelectric Combined

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Hydroelectricity

Grand Coulee Dam photo: http://users.owt.com/chubbard/gcdam/



What it is

Harnessing the power of moving water

The most utilized form of renewable

energy in the world

A virtually emission and waste free

method of generating electricity.

Limited by geography

Flexible



History

Photo: www.silkroadandbeyond.co.uk



figure: www.waterhistory.org

History

Water wheels have been used to do

work for about 2000 years. Most

notably in grist mills and sawmills Three main types: Norse, undershot, and

overshot.



History In the late 1800's people started attaching

water wheels to generators to produceelectricity.

July 1880, First use of hydroelectricity in theUnited states

Hoover Dam

Grand Coulee Dam

TVA

1940's – peak of hydroelectricity use inUnited States, by percentage



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Technological

AspectsWater Wheels, Turbines, and Making Things Spin

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Falling Water

Must spin a

generator

Gravitationalpotential energy

Captured using a

turbine

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How Much Energy Can We Get?

mgh = (1/2)mv2

(1kg H2O/s)(9.8m/s)(100m) = 980 W

At 85% efficiency, that’s 833 W

Head height and water flow

Head heights range from 3 m to over

300 m



Turbine Types

Reaction

Pressure Change

Fully Encased

Francis Turbine

Kaplan Turbine

Impact

Velocity Change

Uses Water Jet

Pelton Wheel

Turgo Turbine





Francis Turbine

Grand Coulee Dam



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Francis Turbine

Most common

Over 90% efficient

Best usage High Flow

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Kaplan Turbine

Bonneville Dam -- In

use for 61 years



Kaplan Turbine

Pivoting blades

Over 90% efficient

Wide usage High Flow

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Pelton Turbine

Walchensee, Germany



Pelton Turbine

Extremely efficient

Conservation of

kinetic energy Scaleable

Multiple nozzles

Low Flow High Head

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Turgo Turbine

Commercial Gilkes Turbine



Turgo Turbine

Less expensive than

Pelton

Exiting water doesnot interfere

Higher Flow

Medium Head

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Crossflow/Banki Turbine

Extracts power

twice

Not as efficient Cheap and easily

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Copyright "Layman's Guidebook on How to Develop a Small Hydro Site"

Published by the European Small Hydropower Association



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Pumped-Storage Electricity

Turbines work in

reverse during off-

peak hours Reaction turbines

Only large

electricity storage

method

Low Energy Density

70-85% efficient

Evaporation Mechanical

inefficiencies



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Social Aspects

Cost: at about 0.85 cents per kWh,

hydroelectricity is relatively cheap.



Recreation

Lakes created by dams create recreational

opportunities including: fishing, water

sports, boating, and water fowl hunting. Much land around reservoirs is open to the

public for activities including hunting,

hiking, skiing,camping, and picnicking

Some are also wildlife refuges



Safety

People can be and are killed and injured

around dams.

Most of these accidents could have beenprevented by staying out of restricted zones

and obeying warning sings and signals.

There is a slight risk of a major dam failure

that could result in a major loss of life

1889 Johnstown flood: 2209 people were killed

when a dam broke



photo: http://orion.fken.ise.osaka-sandai.ac.jp/

Relocation

When a new dam is built people and

structures may have to be relocated

Aswan High Dam, Egypt: Abu Simbel

Kinzua Dam, PA: Seneca Nation



Hydropower and the

Environment

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The Effects of Creating a Large Lake



Environmental Impacts

Greenhouse Gases

Fish Habitat

Wildlife Habitat Land Disturbance

Flooding

Mercury Release

Hoover Dam and Lake Mead

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Possible Solutions

Clear vegetation

Fish ladders Land studies

In-stream, run-off

generators

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John Day Dam, Colombia River



Resources

http://www.wvic.com

http://www.canhydropower.org

http://www.waterhistory.org/histories/waterwheels

http://www.energy.gov/energysources/hydropower.htm

http://www.hydro.org/

http://www.usbr.gov/

http://users.owt.com/chubbard/gcdam/

http://www.nwcouncil.org/library/2003/2003-20/hydro.htm

http://www.centreforenergy.com/

http://www.solareco.com/articles/article.cfm/id/34

http://www.phy6.org/stargaze/Spelton.htm

http://www.gilkes.com/hydro/turgo.htm

http://www.du.edu/~jcalvert/tech/fluids/turbine.htm

http://microhydropower.net/turbines.html

Images

www.silkroadandbeyond.co.uk

http://orion.fken.ise.osaka-sandai.ac.jp/

"Layman's Guidebook on How to Develop a Small Hydro Site”

http://www.unama-afg.org/news/_photos/Flood/_imgpages/Ghazni/Image1.htm








http://www.silkroadandbeyond.co.uk/





http://www.silkroadandbeyond.co.uk/










hydroelectric combined

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