Unit 2 - Electricity
This units explains what electricity is, where it comes from, what we mean by “energy efficiency” and includes activities that measure electricity use at home and in school. The background reading introduces the concepts tested in;
Activity 1 - Test your personal energy efficiency rating
Activity 2 - Power survey of household appliances
Activity 2 datasheet
Activity 3 - Collecting data on school electricity use from old bills
Activity 3 datasheet
Background – An introduction to electricity
What is electricity?
Electricity is a form of energy. Electricity is a lot of electrons flowing in a current. We call this an electrical current. Electricity is so useful because it can be easily converted to other types of energy. Take for example, your television set – in this electrical appliance, electrical energy is converted into light energy and sound energy.
Where does electricity come from?
The power needed to produce electricity comes from many different sources eg. Coal, peat, wind and water. These sources are used to power turbines and generators. These turbines spin around to cause a build up of electrical charge in a generator which makes an electrical current flow.
Turbines are powered by renewable or non-renewable sources of energy. Non-renewable sources of energy are called fossil fuels and include coal, oil, gas and peat. They are burned to heat water for steam powered turbines. Burning fossil fuels releases gases which harm environment.
Wind, hydro, solar and biomass are all sources of renewable energy. The blades in a wind turbine turn a generator to produce electricity.Renewable sources of energy are by far the better option but provide just 6% of the total installed electrical capacity and 2% of all energy required inIreland. The rest, 92% of our electricity comes from burning fossil fuels.
Click here to see a turbine in action.
What do we mean by “energy efficiency”?
Energy efficiency means not wasting energy. It refers to appliances, buildings and even to human behaviour! If you are only making one cup of tea but your boil a full kettle of water, that’s not very efficient is it? Energy is waster in heating more water than is needed. Appliances also waste electricity. They always take in more energy tan gets put to good use. For example, a television converts electricity into light and sound energy, which is great, but some also gets converted into heat, which is a waster. No energy conversion process is 100% efficient but the more efficient the process, the less energy is wasted.
