P1.4 Methods we use to generate electricity

Question 1

What are some energy resources that are used in a power station?

Answer 1

1) Fossil fuels (coal, oil, gas)- burnt to heat water or air
2) Radioactive materials (uranium, plutonium)- energy from nuclear fission is used to heat water
3) Biofuels- burnt to heat water

Question 2

Describe the start up times of the different substances used to make electricity in a power station

Answer 2

Nuclear- longest start up time

Natural gas- shortest start up time

Question 3

Describe wave power and its advantages and disadvantages

Answer 3

As waves come to shore, they provide an up and down motion which can be used to drive a turbine.

• No pollution, no fuel costs, provides useful energy for small islands
• Spoils view, hazard to boats, unreliable as waves die out when wind drops

Question 4

Describe hydroelectricity and its advantages and disadvantages

Answer 4

Usually requires flooding a valley by opening a dam. Water is allowed through turbines.

• Provides an immediate response to an increased demand in electricity, minimal running costs
• Big impact on environment- flooding causes loss of habitat, unreliable if there is a drought

Question 5

Describe wind power and its advantages and disadvantages

Answer 5

Each wind turbine has its own generator inside. Electricity is generated directly from the wind turning the blades which turn the generator.

• No pollution, no permanent damage if they are removed
• Noisy, unreliable, spoil view

Question 6

Describe solar cells and their advantages and disadvantages

Answer 6

Generate electric currents directly from sun light. Often used to power road signs and satellites.

• No pollution, low running costs
• Only reliable in sunny countries, initial costs are high, expensive to connect to national grid

Question 7

Describe geothermal energy and its advantages and disadvantages

Answer 7

In volcanic areas steam + hot water rise from the ground. Steam is used to drive a generator.

• No environmental problems
• Not many suitable locations, cost of building a power plant is high compared to amount of energy you get from it.

Question 8

Describe tidal power and its advantages and disadvantages

Answer 8

Tidal barrages are big dams built across river estuaries with turbines in them. As the tide comes in it drives the turbines. The water is allowed back through the turbines at controlled speeds.

• No pollution, reliable, excellent for periods of peak demand
• Prevents free access by boats, spoils view, alters habitat of wildlife

Question 9

Describe pumped storage and its advantages and disadvantages

Answer 9

Water is pumped into a high reservoir. This is released quickly through turbines in times of peak demand.

• Good way of storing energy, can meet high demand
• Noisy, initial costs are high

Question 10

Describe carbon capture (CCS)

Answer 10

To prevent carbo dioxide building up in the atmosphere we can catch it then store it in empty oil and gas fields like those under the north sea

It is a rapidly evolving technology

Question 11

What are some disadvantages of using biofuels to make electricity?

Answer 11

• Leads to deforestation

- there is a limited amount of farmland that can be dedicated to their production.

Question 12

What is the order of essential parts to the national grid?

Answer 12

Power station- step up transformer- pylons- step down transformer- consumer

Question 13

What is the role of a step up transformer?

Answer 13

Increases the voltage, decrease the current which reduces the energy lost as heat through the cables.

Question 14

What is the role of step down transformers?

Answer 14

Decreases the voltage to safe useable levels and increases the current

Question 15

What are the 2 ways electricity can be transfered around the country?

Answer 15

• over head power lines

- underground cables

Question 16

What are the advantages and disadvantages of overhead power lines?

Answer 16

higher maintenance, ugly, effected by weather, less reliable

lower set up costs, easy to access, easy to set up, minimal disturbance to land

Question 17

What are the advantages and disadvantages of underground cables?

Answer 17

higher set up costs, harder to access, hard to set up, disturbance to land

minimal maintenance, hidden, not affected by weather, reliable

Question 18

How can supply of electricity be increased?

Answer 18

opening more power plants and increasing their power output

Question 19

How can the demand for electricity be reduced?

Answer 19

encouraging consumers to use more energy efficient appliances and being more careful not to waste electricity in their homes.

Question 20

How is electricity made in a power station?

Answer 20

energy source is used to heat water. Steam produced drives a turbine that is coupled with an electrical generator.

Question 21

What are some environmental advantages of burning wood to heat a home rather than using electricity generated from fossil fuels?

Answer 21

wood is renewable

using wood conserves fossil fuels

wood is carbon neutral

Question 22

give some environmental advantages of turning off electrical appliances when they are not being used

Answer 22

conserves fossil fuels

less pollutant gas is produced

Question 23

Name the process by which nuclear fuel provides the energy needed to generate electricity in a nuclear power station

Answer 23

nuclear fission

Question 24

Explain how the National Grid system reduces the amount of energy lost as heat

Answer 24

Step up transformers increase the current and so decrease the current

the smaller the current the smaller the energy lost

Question 25

What can gas be used to do because it has a short start up time?

Answer 25

It can be switched on quickly so can be used to meet surges in demand

Question 26

What are some ethical complications of using energy resources to generate electricity within developed countries?

Answer 26

• unequal use of energy resources
• should be fair access for everyone
• Consequences for he future of decisions made now
• Damage to global environment affects everyone, including people in developing countries who do not use electricity

Question 27

What is meant by a reliable way of generating electricity?

Answer 27

The source does not rely on uncontrollable factors

Can generate all the time

Question 28

What does it mean to decommission a nuclear power station?

Answer 28

Remove radioactive waste

Question 29

How can companies generate electricity and reduce carbon emissions?

Answer 29

Reduce the use of fossil fuelled power stations

use more nuclear power

use more renewable energy sources

Make power stations more efficient

Carbon capture

Question 30

What does the waste energy from a power station have on the surroundings?

Answer 30

it warms the surroundings

Question 31

What is the National grid?

Answer 31

a system of cables and transformers

Question 32

If energy produced in a power station is used locally and so is not transmitted through the national grid, why is the efficiency increased?

Answer 32

as less energy is wasted

this is because energy is lost as heat when transmitted through cables

Question 33

What is the importance of the short start up time in power stations

Answer 33

can be used to meet surges in demand

Question 34

suggest why using wind turbines may cause fluctuations in the electricity supply

Answer 34

turbines do not generate at a constant rate and wind fluctuates and is unreliable

Question 35

Suggest why the amount of electricity used for lighting in homes has decreased

Answer 35

due to energy efficient lighting

increased energy cost so people are more likely to turn lights off

more people are becoming environmentally aware

Question 36

Explain an environmental advantage of taking methane gas from coal mines and using it to generate electricity

Answer 36

less methane goes into the atmosphere

therefore makes global warming less rapid

Question 37

Give examples to explain why electricity is essential for both improving public health and for modern communications

Answer 37

many devices transform electricity into other useful forms of energy

eg refrigeration of vaccines

eg telephones

Question 38

Why are non renewable power stations often more reliable than non renewable power stations?

Answer 38

as fuel is always available for non renewable power stations

but most renewable energy sources are unpredictable so are not reliable

Question 39

Give advantages and disadvantages of using nuclear power station than gas fired station

Answer 39

produces no carbon dioxide, longer operating life

produces radioactive waste, longer start up time

Question 40

why do wind turbines not operate at a high out put all the time?

Answer 40

as wind is unreliable

Question 41

Describe how energy is generated in a hydroelectric powerstation and the useful energy transfers that take place

Answer 41

water moves from a high level to a lower level

transferring gravitational potential energy to kinetic energy

rotating a turbine to turn a generator

transferring kinetic energy to electrical energy