Generating Electricity...

Fuel for electricty, nuclear fuel, energy resources, energy and the enviroment, electricty distribution

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Fuel for Electricty...

In most power stations water is heat to produce steam. The steam then drives turbines which are coupled to an electrical generator that produces electricity. Fuel is burned to produce heat energy to boil the water. Coal, Oil and Natural Gas are fossil fuels. They are burned in fossil fuel power stations. Fossil Fuels are obtained from long-dead biological material.

Bio-fuels are renewable sources of energy which can generate electricity. A bio-fuel is any fuel obtained from a living or recently lining organisms.

Nuclear power stations use uranium or plutanium for their fuel. The nucleus of a uranium or plutanium atom undergo a process called nuclear fission. This process releases energy. There are lots of uranium nuclei so lots of fission reactions can take place. This energy is then used to heat water, which will produce steam to turn the turbines.

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Fuel for electricty...

Key points:

  • Electricity generators in power stations are driven by turbines.
  • Coal, Oil and Natural Gas are burned in fossil fuel power stations
  • Uranium or Plutonium is used as the fuel in a nuclear power stations
  • Bio-fuels are renewable sources of energy which can generate electricity
  • most power stations burn fuels to produce energy to heat water. In a nuclear power station uranium is not burned, the energy come from the process of nuclear fission. 
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Coventional (Fossil Fuel) Power Stations..

(http://www.bbc.co.uk/schools/gcsebitesize/science/images/20_the_national_grid.gif)

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Coventional (Fossil Fuel) Power Stations..

1. Fuel is burned to boil water and produce steam

2. Steam provides kinetic energy to rotate the turbine

3. The spinning turbine powers the generator to produce electricity

4. Electricity goes to transmission lines for distribution.

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Nuclear Power Station...

(http://www.freeinfosociety.com/images/science/nuclearenergy1.jpg)

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Nuclear Power Station...

Energy transfers in nuclear power station:

  • nuclear - heat
  • heat - kinetic
  • kinetic - electrical

The fuel used is either uranium or plutonium

Compare and Contrast:

Much more energy is released per kilogram of uranium undergoing fission reaction than from each kilogram of fossil fuel that we burn.

Nuclear power stations do not produce greenhouse gases unlike fossil fuel power stations (carbon dioxide and sulfur dioxide) although they do produce nuclear waste.

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Energy Resources

Non-Renewable - once used cannot be replacedon time scale of appropriate human use. Examples:

  • Oil
  • Coal
  • Gas
  • Nuclear

Renewable - those that can be replenished on a time scale of appropriate human use. Examples:

  • Wind
  • Solar
  • Tidal
  • Wave
  • Hygroelectric
  • Biomass
  • Geothermal
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Wave Power

(http://www.daviddarling.info/images/wave_power_diagram.gif)

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Wave power

  • Waves make the water in the air chamber rise and fall, causing the air to turn the turbine.
  • The movement drives fa floating turbine that drives the generator.
  • Electricity is delivered to the grid system on the shore, by cable.

Pros...

  • Renewable
  • no waste gases

Cons...

  • no constant energy
  • a lot of cabling is necessary
  • has to sustain harsh weather
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Tidal Power

(http://technologystudent.com/images5/tidal1.gif)

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Tidal Power

  • This tidal electricity generation works as the tide comes in and out again. The turbines are driven by the power if the sea in both directions.
  • The level of the sea around the coastline rises and falls twice each day.

Pros...

  • Renewable
  • Reliable
  • Fuel Free

Cons...

  • can effect habitats of animals
  • requires a long stretch of generators
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Hydroelectric Power

(http://atlas.nrcan.gc.ca/auth/english/maps/freshwater/consumption/hydro_generation.jpg)

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Hydroelectric Power

  • The water, at a hydroelectric power station is collected in a reservoir.
  • This water is allowed to flow downhill and turn turbines at the bottom of the hill.
  • In a pumped storage system, surplus electricity is used, at time of low demand to pump the water back up the hill to the top of the reservoir.
  • This means the energy is stored. Then at times of high demand the water can be released to fall through the turbines and transfer the stored energy to electrical energy.

Pros...

  • Renewable
  • Reliable
  • Respond rapidly to demand

Cons...

  • Affects animal habitats and farm land
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Wind power...

(http://www.ecovolt.ro/en/support/images/turbine_diagram.jpg)

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Wind power...

  • A wind turbine is an electricity generator on top of a tall tower.

Pros.....

  • Renewable
  • No fuel costs
  • No waste gas

Cons....

  • Unreliable
  • Affects animal habitats
  • Noises (low frequency noise has health implications)
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Solar Power...

(http://www.easy-green-living.org/images/solar-energy-diagram.gif)

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Solar Power...

  • A solar cell can transfer energy into electrical energy
  • Each cell only produces a small amount of electricity
  • Large numbers of cells are put together to form solar panels
  • Water flowing through a solar heating panel is heated directly by energy from the sun
  • A solar power tower uses thousands of mirrors to reflect sunlight onto a water tank to heat the water and produce steam

Pros....

  • clean, endless and green
  • no fuel costs and cheap after set-up
  • renewable

Cons...

  • expensive to buy and install and takes up a lot of space
  • Unreliable
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Geothermal Power...

(http://www.reuk.co.uk/OtherImages/geothermal-power-plant-schematic.jpg)

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Geothermal Power..

Geothermal energy is produced inside the earth by radioactive processes and this heats the surrounding rock. In volcanic or other suitable areas, very deep holes are drilled and cold water is pumped down to the hot rocks. There it is heated and comes back up to the surface as steam. The steam is used to drive turbines that turn generators and so electricity is produced.

Pros...

  • no waste gases
  • no fuel costs

Cons...

  • only avliable in a small number of places in the earth eg. Iceland
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Biomass

Biomass refers to chemical energy from crops such as sugar, maize and a variety of other crops and trees. This can be used to make a variety of fuels for heating, transport and electricity generation.

Pros...

  • Renewable
  • no waste gases
  • carbon neutral energy source

Cons...

  • Alot of land needed
  • land which could be used to grow crops for food
  • prices of food will rise
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Energy and the Enviroment

Key Points:

  • Burning fossil fuels produces greenhouse gases that cause global warming
  • Nuclear fuels produce radioactive waste
  • Using renewable energy resources can affect plant and animal life
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Electricity Distribution...

(http://1.bp.blogspot.com/_2bc78qjWZc8/TN_eVHVWTRI/AAAAAAAAAxc/umjHDVdM91g/s1600/how+electricity+delivered+to+our+home.JPG)

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Electricity Distribution..

Key Points:

  • National Grid distributes electricity from power stations to our homes
  • Step-up and Step-down transformers are used in the National Grid
  • A high grid voltage reduces energy wastage and makes the system more efficient
  • Step-up transformers increase voltage, Step-down transformers decrease voltage.
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Comments

yoona

thnx alot

grazielle johnson


she helped me a lot so I would like to say thanks so much but it would have been even better if she had make a powerpoint thx so much

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