Transcript Hydropower Dams - Hopkinton School District

Hydropower Dams
By: Brittany Marshall and Maddy
Bergethon
Basics
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Relies on the water cycle
AC (alternating current) or DC (direct current)
AC is easier to use
Mechanical energy is harnessed from the
water and used to spin the turbines
History
Using water for energy= back to Romans and
Egyptians= water wheel
First water source to make electricity was in
1882
1903 began the rush of making them
Pros
• Very reliable power source
• Generates a lot of power
Cons
Causes lots of flooding
Displaces wildlife= suffering
Migrating fish= dying
Weird Fact
• New Scientist claims that hydropower dams
actually produce more greenhouse gasses
than fossil fuel plants
• By deforestation
Turbine Types
• Impulse–
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changes potential energy to kinetic energy
uses Newton’s 2nd law of motion
takes momentum of water and forces turbines to move
doesn’t have to be submerged or enclosed
Turbine Types
Reaction
Use water pressure to
spin turbine
Has to be incased or
completely under water
Most common type
Uses Newton’s 3rd law of
motion
Maintenance
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Designed to run for a long time
Little maintenance
Water erosion
Gets hit by rock/stick or other debris in water
Steps of Hydropower Dam
1. Dams holds water back in reservoir
2. Gates open and gravity pulls water through
penstock and into powerhouse; pressure
builds
3. Water hits large blades of turbine making
them turn
4. Turbine blades turn together with series of
magnets in generator
5. Magnets rotate past copper coils= AC current
Steps Continued
6. Transformer converts
AC to higher voltage
7. Goes through power
lines to customers
8. Used water is carried
through overflow
pipes and goes back to
river; downstream
Hydropower in the US
• Largest renewable
resource
• 7% of our power
• #2 producer with 306
billion kilowatts per hour
(Canada = #1)
• Generate enough to
support 28 million
households
• = 50 million barrels of gas
Hydropower in the World
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24% of the world electricity
674,000 megawatts
Equivalent to 3.6 billion barrels of oil
Supply 1 billion people with power
88% of the renewable energy sources
Norway= 99%!!!!!!!!!!!!!!! WOW!!!!!!!!!!! 
Hydropower in the World
Top 3
1. Three Gorges Dam- China, construction started in
2008 and has not yet been finished when finished
will generate around 22,500 megawatts.
2. Itaipu- Brazil & Paraguay, finished in 2003, generates
around 14,000 megawatts
3. Guri- Venezuela, completed in 1986, generates
around 10,200 megawatts
Citations
• http://drake.marin.k12.ca.us/stuwork/rockwa
ter/Upload%20this%20doc-dams%20and%20hydropower%20report/histo
ry,%20water%20project.html
• http://www.waterencyclopedia.com/GeHy/Hydroelectric-Power.html
• http://www.morriscanal.org/tech.htm
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