How can electricity be generated?

Question 1

Why is energy used or important?

Answer 1

everything requires energy and a way to use energy is to transfer it from one energy store to another.

Question 2

What are energy resources?

Answer 2

systems that can store large amounts of energy

Question 3

What are the important energy resources to produce electricity?

Answer 3

fossil fuels, nuclear fuel, bio-fuel, wind, hydroelectricity, geothermal, tidal, water waves and the Sun

Question 4

Where does all energy on Earth come from?

Answer 4

the sun but has been stored as different energy sources

Question 5

What is energy needed in?

Answer 5

homes - for cooking, heating, etc.
public services e.g. schools and hospitals for running warm rooms and machinery
factories and farms - operating heavy duty machines
transport - cars, buses, trains all need a fuel source

Question 6

What can cause damage to the enviroment?

Answer 6

producing and distributing electricity

releasing energy from some stores causes pollution and harmful waste products

Question 7

What are some trends in using energy resources?

Answer 7

in 20th century, electricity became a way of distributing energy that can be used for many devices such as computing technologies, lighting, heating, etc.

during early evenings, a lot of energy is needed for heating, lighting and cooking but overnight little is needed while people sleep

Question 8

Why is most of the electricity generated still produced by fossil fuels?

Answer 8

the high power output fossil fuels give compared to other resources like wind and water

the existing infrastructure for transporting, extracting and processing fossil fuels which makes them cheaper

Question 9

What do most countries agree?

Answer 9

the use of fossil fuels should be reduced to limit the emission of the greenhouse gases that cause climate change

the cause of burning fossil fuels has causes society to develop the use of renewable energy resources

Question 10

What are nuclear power stations?

Answer 10

a growing form of electricity generation

nuclear fuel can release large amounts of energy and does not emit carbon dioxide

Question 11

How can renewable resources be replenished?

Answer 11

by human action or natural processes

human action - e.g. cutting trees down
natural processes - e.g. let water through a dam for hydroelectricity which is replaced through the water cycle

Question 12

What are different energy resources?

Answer 12

fossil fuels - high power output

nuclear fuels - very high power output

biofuels - medium power output -

wind - very low output -

hydroelectricity - medium power output

geothermal - medium power output

tides - very high power output

sun - dependent on weather power output

water waves - low power output

Question 13

What are the power stations that use fossil fuels or nuclear fuel?

Answer 13

they are very reliable sources of energy

two types of stations - gas power stations or hydroelectric power stations - they come on very quickly and start generating electricity quickly

the fuel for nuclear power stations is cheap but xpensive to build

Question 14

Why is water power reliable?

Answer 14

e.g. tidal and hydroelectricity

because the moon causes the tides and rainfall filling reservoirs

they can be used to supply demand for energy

has no cost but expensive to build

Question 15

How is electricity generated?

Answer 15

generators in a power station produces electricity when a coil of wire is in a changing magnetic field - which is caused by spinning a magnet inside the coil

fossil fuel and nuclear power stations use the energy store to heat water and produce steam to turn a turbine which is connected to magnet to make it spin

Question 16

What is the national grid?

Answer 16

electricity is generated in power stations and transported across the UK

it is very efficient

Question 17

How do you move power around the national grid?

Answer 17

before electrical power leaves a power station - it is transferred at high voltages by using step up transformers to increase the voltage to 275k V or 400k V

before electrical power enters homes and factories the voltages are decreased by ‘step-down’ transformers to 33,000 V (large factories), 11,000 V (medium factories), 230 V (homes, shops, small factories and offices)

Question 18

What is a set-up transformer?

Answer 18

can change the voltage of an alternating current (ac). A basic transformer is made from two coils of wire ‐ a primary coil from the ac input and a secondary coil leading to the ac output. The coils are not electrically connected. Instead, they are wound around an iron core. This is easily magnetised and can carry magnetic fields from the primary coil to the secondary coil.

Question 19

What are step down transformers?

Answer 19

Step-down transformers are used to decrease or ‘step-down’ voltages. These are used when voltages need to be lowered for use in homes and factories. A step-down transformer has fewer turns of wire on the secondary coil than on the primary coil. This transformer steps down the voltage by increasing the current.

Question 20

What is mains electricity?

Answer 20

energy brought into peoples home

The UK mains supply is connected to appliances in the home by using a plug. The plug contains three wires ‐ the live, neutral and earth wires.

Question 21

What is the live wire and neutral wire?

Answer 21

the two wires that form the complete circuit with a household appliance.

Question 22

What is the earth wire?

Answer 22

not part of the circuit and is a safety wire

it is connected to earth which is a large metal spike buried under a house

Question 23

What are the three safety features found in plugs and appliances?

Answer 23

the fuse, double insulation and the earth wire

Question 24

What is the fuse?

Answer 24

to melt if a current flows through it that is too large

if the current gets too high, too much heat can be produced which can cause a fire to the appliance

Question 25

What is double insulation?

Answer 25

contains metal parts surrounded with a casing made from a plastic insulation

stops the user from coming into contact with any metal parts that conduct current

coming into contact with these areas can cause electrocution

Question 26

What is the earth wire?

Answer 26

allows large current to pass through the fuse when a live wire loosens and touches a metal part of the appliance

if there is no earth wire, and a live wire was loose, touching the appliance would cause the person to be electrocuted as a high current would pass through the body to the ground