P1 - Generating Electricity

Question 0

How is electricity generated in a power station?

Answer 0

Generators are driven my turbines.

Question 1

Which fossil fuels are burnt in power stations?

Answer 1

Coal, oil and natural gas

Question 2

Which elements are used as fuel in nuclear power stations?

Answer 2

Uranium or plutonium

Question 3

What other fuels can be used to generate electricity?

Answer 3

Biofuels such as methane and ethanol

Question 4

Describe the process of generating electricity in a …-fired power station.

Answer 4

• Burning fuel heats water in a boiler producing steam.
• Steam drives a turbine.
• Turbine turns generator.

Question 5

Where do fossil fuels come from?

Answer 5

Long-dead biological material.

Question 6

Where can methane be sourced from?

Answer 6

Animal manure
Decaying rubbish
Sewage works

Question 7

Where does biofuel come from generally?

Answer 7

Living or recently deceased organisms.

Question 8

How is biofuel a renewable energy source?

Answer 8

It’s biological source continues to exist and never dies as a species.

Question 9

How are biofuels carbon-neutral?

Answer 9

The carbon the organism takes in is equal to the CO2 released when burnt.

Question 10

Explain nuclear fission.

Answer 10

The nucleus of a U-235 atom is split which releases energy.

Question 11

Explain how energy is transferred to electricity from nuclear fission.

Answer 11

The energy released from nuclear fission heats a coolant which boils water. The steam then turns a turbine.

Question 12

Give two advantages of nuclear power

Answer 12

• Lots of energy is released

- There are no greenhouse gases

Question 13

Give two examples of renewable energy.

Answer 13

Hydroelectric and solar (PV)

Question 14

What is a wind turbine?

Answer 14

An electricity generator at the top of a tower.

Question 15

How can waves be used to generate electricity?

Answer 15

The movement of the waves turns a generator.

Question 16

Give three disadvantages of wave power systems.

Answer 16

• Don’t produce a constant supply of electricity.
• Lots of cable needed.
• Can change tidal flow patterns.

Question 17

How does a hydroelectric plant work?

Answer 17

Water in a reservoir flows downhill, spinning a turbine.

Question 18

How does a tidal power station generate electricity?

Answer 18

Water is trapped at high tide then released through turbines.

Question 19

How efficient are current solar cells?

Answer 19

> 10%

Question 20

Give three disadvantages of PV cells.

Answer 20

• Low efficiency
• Very expensive
• Need lots to generate usable electricity

Question 21

How do solar power towers generate electricity?

Answer 21

• Computer-controlled mirrors reflect sunlight onto tank.

- The sunlight heats the water and the steam turns a generator.

Question 22

What is the source of geothermal energy?

Answer 22

Radioactive substances underground.

Question 23

How is electricity generated from geothermal energy?

Answer 23

• Radioactive substances heat surrounding rocks.
• Water is poured on hot rocks making steam.
• Steam drives a turbine.

Question 24

How can buildings be directly heated from geothermal energy?

Answer 24

Ground heat warms water in pipes which is pumped around a building.

Question 25

How do fossil fuels damage the environment?

Answer 25

Burning fossil fuels releases greenhouse gases which contribute to global warming.

Question 26

Give one concern people might have about nuclear power?

Answer 26

Nuclear fuels produce radioactive waste.

Question 27

How can renewable energy sources affect the environment?

Answer 27

They can affect animals' and plants' habitats.

Question 28

How is acid rain caused?

Answer 28

Burning fossil fuels can release sulfur dioxide which dissolves in water vapour in the air.

Question 29

What is a potential problem with sourcing fossil fuels?

Answer 29

Fossil fuels are non-renewable

Question 30

Give one way of lowering CO2 emissions.

Answer 30

Carbon capture and storage

Question 31

Give two advantages of nuclear energy.

Answer 31

- No greenhouse gases. | - More energy per kilogram.

Question 32

Give two disadvantages of nuclear power.

Answer 32

- Used fuel rods contain radioactive waste that has to be stored. - An explosion would cause disaster over a wide area.

Question 33

Give four advantages of renewable energy sources.

Answer 33

- They will never run out. - They don't produce greenhouse gases or acid rain. - They don't produce radioactive waste. - Can be used in remote areas.

Question 34

Give four disadvantages of renewable energy sources.

Answer 34

- Wind turbines make noises and "blot" the landscape. - Tidal barrages affect plant and animal habitats. - Habitats are often flooded to create dams for hydroelectric. - Solar cells have to cover a large area.

Question 35

What is the National Grid?

Answer 35

A network of cables and transformers that distributes electricity.

Question 36

What do transformers do in the National Grid?

Answer 36

Step-up transformers increase the voltage into the Grid. | Step-down transformers decrease the voltage out of the Grid.

Question 37

Why are high voltages used in the Grid?

Answer 37

High voltage reduces energy loss making the system more efficient.

Question 38

What voltage do power stations generate electricity at?

Answer 38

25,000V (25kV)

Question 39

What is the voltage of the Grid?

Answer 39

132kV +

Question 40

What voltage do home appliances take from a plug socket?

Answer 40

230V

Question 41

Why does a higher voltage make the Grid more efficient?

Answer 41

As the voltage is higher, the current is lower. This reduces the heat energy transferred that is caused by the current.

Question 42

What type of power stations are used to meet variations in demand for electricity?

Answer 42

Gas-fired power stations as well as pumped storage charged by renewable energy sources.

Question 43

What power stations are used to meet base-load demand?

Answer 43

Nuclear, coal and oil power stations.

Question 44

Why are gas fired power stations used to meet variations in demand?

Answer 44

They can be started up instantly.

Question 46

What happens when there is less demand than the base-load?

Answer 46

Energy is stored for when demand is above base-load.

Question 47

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Answer 47

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