Unit D: Electricity

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Unit D Electricity

• Electricity Production and The Environment

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Introduction

• Canadians consume 2 X 1018 J of energy per year
  making us one of largest energy users per capita
  in the world.
• To meet our energy needs a wide variety of energy
  sources from wind power to nuclear power are used.

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Fossil Fuels

• Makes up 25 of energy produced in Canada.
• Fuel oil, natural gas, and coal are all fossil
  fuels.
• Non-Renewable. Natural gas is already
  disappearing from Alberta. Coal and oil sands
  deposits range from less than 50 to 200 years.

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Coal Power Plants

• Typical Power Plant

• Alberta Coal Power Plant

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Coal Power

• After being mined, coal is crushed into powder,
  put into a combustion chamber and burned to
  release heat.
• The heat produced boils water which changes to
  high temperature and pressure steam.
• The steam rises and turns turbines which contain
  large electromagnetic coils. Turning the turbines
  produces electricity.

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Advantages and Disadvantages of Fossil Fuels

• Advantages
• Cheap and available
• Alberta has large fossil fuel deposits.

• Disadvantages
• Coal mines are open pits which destroy ecosystems
  and are ugly.
• Produce tailings acidic ground water.
• Produce greenhouse gases (CO2 and SO2).
• Non-Renewable wont last forever.

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Hydroelectric Power

• Use the gravitational energy provided by falling
  water and water pressure to provide electricity.
• Large dams raise water above power plant, which
  is built near the bottom of the dam.
• A channel called a penstock directs the high
  pressure water to a turbine causing it to spin.
• So gravitational energy is changed to mechanical
  energy which is changed to electrical energy.

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Hydroelectric Power plant
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Advantages and Disadvantages of Hydroelectric
Power

• Advantages
• Cheap energy. As long as there is water were
  fine.
• No pollution produced.

• Disadvantages
• Destroys ecosystems.
• Wildlife such as fish and plants are starved of
  oxygen and die, bacteria thrive.

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Nuclear Power

• Works through the process nuclear fission.
• Nuclear fission Bombarding uranium atoms with
  neutrons causes the uranium atoms to split or
  fission into two smaller atoms.
• The fission of atoms produces a huge amount of
  energy which is used to generate electricity in a
  thermonuclear power plant.

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Advantages and Disadvantages of Nuclear Power

• Advantages
• Small amounts of uranium can produce huge amounts
  of energy.
• Problem of running out of energy sources would be
  solved.
• Energy would be much cheaper.

• Disadvantages
• Any accident could lead to a nuclear meltdown
  releasing radiation into environment.
• Produces radioactive waste which needs to be
  stored.
• Produces thermal pollution.

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Thermal Pollution

• When water is heated and released back to the
  environment it is called thermal pollution.
• Will lead decreased oxygen levels and the killing
  of fish and plants in wetlands.
• To help stop thermal pollution, cooling towers
  are built to cool down water before sending it
  back to environment.

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Renewable Energy

• Wind, geothermal, sunlight, and tide energy are
  all examples of renewable energy since they will
  not run out.
• Geothermal energy is energy supplied by heat
  released by Earths core. Pipes channel hot water
  and steam to drive turbines which supply
  electricity.
• Even these power plants can wreck ecosystems.

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Cogeneration

• Cogeneration The production of electricity and
  heat energy from the same source.
• For example Natural gas can supply both
  electricity and heating for homes.