Electricity Fact Sheet
What is Energy?
Energy is the ability to do work
Energy is required for anything to move or change.
Energy exists in many forms and cannot be created or destroyed. We cannot see, touch or hold it.
Energy can be categorized into either Kinetic (movement energy)
or Potential (stored energy)
Kinetic Energy is movement- the motion of waves, atoms, electrons, substances, molecules and objects.
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Potential Energy is stored energy waiting to be released in a usable form. |
- Electrical energy is the movement of electrical charges made up of electrons, protons and neutrons, called atoms. Electrical charges moving through a wire or cable is called electricity.
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- Chemical energy is energy stored in petroleum, natural gas, biomass and food.
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- Radiant Energy is electromagnetic energy that travels in waves. It includes visible light, x-rays, radio waves, gamma rays and solar energy.
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- Stored Mechanical Energy is the energy stored in objects through the application of force, such as compressed springs and taut rubber bands
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- Motion Energy is the movement of things from one place to another. Wind is an example of motion energy.
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- Nuclear Energy is the energy stored in an atom. Energy is released when the nuclei are split apart or combined.
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- Thermal or Heat Energy is the internal heat in substances. Geothermal energy is an example of thermal energy and is the heat present in the rocks beneath the earth’s crust.
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- Gravitational Energy is the energy of position or place such as a rock resting at the top of a slope or water held in a reservoir behind a dam.
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Table Sources
Energy can be transformed from one form to another.
Here are a few examples:
- Water at the top of Barron Falls in Far North Queensland has potential energy, which is transformed into kinetic energy as the water falls.
- Coal stored at a power station has potential energy until the coal burns releasing heat energy.
- When petrol burns in a car engine, the chemical energy in the petrol is converted into mechanical energy for the car to move.
- Solar cells change radiant energy from the sun into electrical energy.
How many other examples can you name?
How is Energy Measured?
Energy is measured in Joules (J).
The work done or energy consumed is called Power
Power is measured in Joules per second and is called Watts (W).
A Watt is the use of 1J of energy per second.
One Kilowatt = one thousand Watts
One Megawatt = one million Watts
Sources of Energy
Energy resources are described as being non-renewable and renewable.
Renewable and non-renewable energy can be converted into secondary energy sources such as electricity and hydrogen. Secondary energy sources are energy carriers, which are used to store, move and distribute energy in a usable form. Another energy source is used to make electricity or hydrogen. Hydrogen is extracted from natural gas, a non-renewable source. Hydrogen can also be separated from water and other renewable sources.
Non-renewable energy sources such as coal, petroleum and gas are ‘fossil fuels’, which have taken millions of years to form. Fossil fuels are important because they can be burned to create huge amounts of energy. However, they are called ‘non-renewable’ because sources are limited.
Coal is generally the cheapest means of generating electricity. The word ‘petroleum’ comes from two Latin words, rock and oil. It is a liquid called crude oil and is generally referred to as oil.
Fossil fuels were formed from the remains of plants and animals that lived and died hundreds of millions of years ago in the Late Devonian and Early Carboniferous Period when the Earth was partly covered by swampy forests.
As the plants and animals died and sank into the swamp, they were covered by water and soil and layers progressively built up. The weight and heat from the top layers compressed the dead plant and animal remains and eventually, chemical and physical processes changed the material into fossil fuels.
To retrieve coal, petroleum and gas, various methods of extraction are used.
Coal is removed from the ground using either surface (open cut) mining or underground (deep) mining. Petroleum and gas are extracted by drilling into the earth’s surface either on land or on the seabed.
The Energy Information Administration estimated that in 2005, 86% of global primary energy production came from burning fossil fuels.
We are using fossil fuels at a greater rate than they can be replaced. There is a concentrated effort globally to reduce the amount of fossil fuels used and to increase the use of renewable energy sources.
Renewable energy sources are continually being replaced and include energy from the sun, wind and water. Other sources of renewable energy are geothermal energy derived from the heat beneath the earth’s crust, and biomass, which comes directly and indirectly from plants and waste material.
www.sustainableenergy.qld.edu.au Fact Sheet 3.
National Energy Education Development Project (NEED) Energy Kid’s Page ‘Scientific Forms of Energy’. www.eia.doe.gov/kids/energyfacts/science
Energex Switched On ‘Forms of Energy’. www.energex.com.au
International Energy Annual 2005, referenced in Wikipedia ‘Fossil Fuels’
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