National grid

What is the national grid?

The giant network of cables and transformers that covers the UK and connects power stations to consumers

How do we get electricity in our homes?

The national grid

Where does electricity come from in the UK?

Power stations

How do power stations work?

The burning fuel creating thermal energy into electrical energy

What does the amount of electrical energy depend on?

Demand

When does demand increase?

In the late afternoon and evening

How do power stations cope with surges in demand?

They have lots of spare capacity = run below their maximum power energy

What happens when there is a high current flows through a wire?

Generates lots of heat because of its high resistance in the wire = loses loads of energy to the surroundings

How do we avoid a loss of energy via the high current?

We lower the current and raise the voltage

What do step - up transformers do?

Increases the voltage to about 400

Where do the wires transmit the electricity once they have gained it from the step - up transformers?

It is transmitted between pylons across the country via wires

What do the step - down transformers do?

Decrease the voltage to about 230 Volts and increase the current

Why do we need to decrease the voltage via the step - down transformers?

High voltage is dangerous