Electricity and the National Grid

Question 1

What is the national grid?

Answer 1

It is a network of pylons and cables that covers the whole of Britain getting electricity to homes.

Question 2

How does electricity get distributed by the national grid?

Answer 2

The National Grid takes electrical energy from power stations to where its needed in homes / industry.
It enables power to be generated anywhere on the grid and supplied anywhere else on the grid.
To transmit the huge amounts of power needed you need either a high voltage or high current.

Question 3

What is the problem with high current?

Answer 3

You lose lots of energy through heat in the cables.

It cheaper to boost voltage up really high to 400,000V and keep current low.

Question 4

How do pylons and transformers help distribute electricity?

Answer 4

To get the voltage up to 400,000 V to transmit power requires transformers as well as big pylons with huge insulators.
The transformers step voltage up at one end, for efficient transmission.
Bring it back down to safe usable levels at other end.
Voltage increased = using step up transformer.
Reduced again at consumer end by step-down transformer.

Question 5

Name 2 ways to transmit electricity.

Answer 5

Cables buried under ground.

Overhead power lines.

Question 6

Pros and cons of overhead power lines.

Answer 6

Low set up cost.
Easy to access.
Easy to set up.
Minimal disturbance to land.
Lots of maintenance needed.
Looks ugly, affected by weather and unreliable.

Question 7

Pros and cons of underground cables.

Answer 7

Minimal maintenace.
Hidden.
Not affected by weather.
Reliable.
Cost a lot.
Hard to access,  Hard to set up, lots of disturnace to land.

Question 8

Supply and demand.

Answer 8

In order to meet energy demands the energy supplied to the National Grid will need to increase or the energy demands of consumers will need to decrease.

Question 9

Supply and Demand.

In the future what can we do.

Answer 9

Supply can be increased by opening more poweer plants or increasing their power output.
Demand reduced by consumers using more energy efficient appliances not wasting energy at home.