# The National Grid

In this worksheet, students will learn how electricity is generated in power stations and the distribution of electricity through the National Grid.

Key stage:  KS 4

Difficulty level:

### QUESTION 1 of 10

The National Grid distributes electricity around the United Kingdom as high as 400,000 Volts (or 400 kV). High voltage means that there is an energy-saving - distribution costs are less and electricity is cheaper for consumers. Transformers used in the National Grid reduce or increase the voltage. Large industries use 33 kV electricity; hospitals, schools and smaller industries use electricity at 11 kV, and houses, shops and farms at 240 V. Some of the energy is lost as heat to the environment. The diagram below shows National Grid pylons:

Electricity is produced at power stations. The diagram below shows what happens in different parts of a power station. Coal burns in the furnace and water steam is produced in the boiler. The steam turns the turbine under high pressure and the generator generates electricity. Eventually, a transformer changes the voltage so electricity can be distributed through the National Grid.

Through what is electricity distributed around the UK?

What is the voltage that electricity is produced in a power station in kV?

400,000

4,000

400

What voltage is used by houses in the UK?

11 kV

33 kV

230 V

What do tranformers do?

They generate electricity

They step up (increase) or step down (decrease) the voltage

They distribute electricity

Why is high voltage useful? Three options apply.

It reduces energy loss

It reduces time taken to generate electricity

It is less dangerous

It reduces distribution cost

It ensures electricity is cheaper for consumption

Where is coal burnt in a power station?

In the furnace

In the turbine

In the generator

Why is there a boiler in a power station?

It transforms voltage

It generates electricity

Steam that turns the turbine is produced in the boiler

Where does the energy needed to produce steam in the boiler come from?

From the turbine

From the furnace where coal is burnt

From the generator

What does the generator do in a power station?

It decreases energy loss

It turns the turbine

It makes electricity

What happens to the electricity after the step-down transformer?

It is distributed to consumers

It has its voltage changed

It is lost to the environment

• Question 1

Through what is electricity distributed around the UK?

National Grid
The National Grid
EDDIE SAYS
Electricity is distributed around the UK through the National Grid. Note the use of capital letters for both words because it is a name.
• Question 2

What is the voltage that electricity is produced in a power station in kV?

400
EDDIE SAYS
Electricity is produced in a power station at 400 kV. This is the same as 400,000 V (Volts). It is so high because this makes it more efficient to move the electricity around.
• Question 3

What voltage is used by houses in the UK?

230 V
EDDIE SAYS
Houses in the UK use electricity at 230 V. 'V' for voltage must always be written in capitals.
• Question 4

What do tranformers do?

They step up (increase) or step down (decrease) the voltage
EDDIE SAYS
Transformers step up (increase) or step down (decrease) the voltage. They will step up the voltage when it is travelling through the high tension wires and step down the voltage again before it reaches your house.
• Question 5

Why is high voltage useful? Three options apply.

It reduces energy loss
It reduces distribution cost
It ensures electricity is cheaper for consumption
EDDIE SAYS
High voltage reduces energy loss, reduces distribution cost and ensures electricity is cheaper for consumption. Less energy loss means that less fuel is needed to make the electricity - this, in turn, lowers the price of the electricity.
• Question 6

Where is coal burnt in a power station?

In the furnace
EDDIE SAYS
Coal is burnt in the furnace of a power station. This is used to heat up water to make steam. The steam is then used to drive the turbines.
• Question 7

Why is there a boiler in a power station?

Steam that turns the turbine is produced in the boiler
EDDIE SAYS
The boiler in the power station is necessary because it produces the steam that is used to turn the turbine. Steam is the most effective way of doing this as it is the most efficient (up to 50%).
• Question 8

Where does the energy needed to produce steam in the boiler come from?

From the furnace where coal is burnt
EDDIE SAYS
The energy that is needed to produce the steam (which then turns the turbine) comes from the furnace. This can be from burning coal, oil, gas, biomass of nuclear fuel. They all work the same way, as does 90% of our energy generation.
• Question 9

What does the generator do in a power station?

It makes electricity
EDDIE SAYS
The generator makes electricity by spinning magnets in a coil of wires. We will look at this in more depth in a later activity.
• Question 10

What happens to the electricity after the step-down transformer?

It is distributed to consumers
EDDIE SAYS
After the transformer, electricity is distributed to consumers through the National Grid. Option 1 is correct, but there is some truth to Option 2 (it has its voltage changed) because it may need to be 'transformed' again depending on who it will go to. The important thing to look at here is if it is a step up or a step-down transformer. Step up makes the voltage go up, and step down makes the voltage go down.
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