Why is electricity the most convenient form of energy to use?
- It is clean.
- It can travel over long distances along wires.
- It can easily be changed into other forms of energy, such as heat and light.
- To use the electricity connected to your home, all you have to do is to switch it on or plug an appliance into an electrical outlet.
The world is full of electrical energy, but most of it is in a form we cannot use. Lightning is one example of electrical energy that we cannot use. We can’t convert the electrical energy in a flash of lightning into useful electricity. Most of the electricity we use in our homes is made by generators at power stations. These generators are really energy converters. They convert kinetic energy at the power station into electrical energy.
The kinetic energy is produced by burning fuel, by moving water, or by wind power.
What is an electricity grid?
One problem with electrical energy from power stations is that it cannot easily be stored. Once the electrical energy has been made, it must travel along the cables and wires to where it is needed. Most power stations are linked to a network of cables called a power pool. When there is a big demand for electricity—for example, for air conditioning during very hot weather—more power stations send electricity into the power pool. When less energy is needed, some of the power stations reduce the amount of electricity they produce. Some countries make more electricity than they need. They sell the spare energy to countries which do not have enough.
Making your own electricity
Do you have a lamp on your bicycle? If you do, this means you may have a simple type of generator, called a dynamo, to make the lamp shine. The dynamo contains a strong magnet which rotates when the bicycle wheel turns. An electric current starts to flow in a coil of wire near the rotating magnet. The dynamo converts the kinetic energy of the turning wheel into electrical energy to light the lamp. You can easily see this working if you turn your bicycle upside down and turn the pedals by hand.
You can make electricity yourself if your bicycle has a dynamo.
The generators in a power station work in much the same way as a dynamo.
Wires carry the supply of electricity from this power station to places where it is needed.