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GCSE Physics (P1) > Generating Electricity > Flashcards

Generating Electricity Flashcards

1
Q

How do most power stations work?

A
  • Water is heated to produce steam
  • The steam drives a turbine, which is coupled to an electrical generator.
  • This generator converts the kinetic energy to electrical energy and thus generates electricity
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2
Q

How are fossile fuels obtained/what are they?

A

Long-dead biological material that has been compressed under high pressure to form carbon compounds. Obtained by drilling/mining (coal)

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3
Q

How do gas fire power stations and hyroelectric (HEP) power stations differ from the standard power station model?

A

In gas-fired power stations, the hot gas drives the turbin directly.

In HEP, the water drives the turbin (grav. potential -> kinetic -> electric)

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4
Q

What is burned in fossil-fuel powered power stations?

A

Coal, oil, and gas

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5
Q

What is used as fuel in a nuclear power station?

A

Uranium or plutonium

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6
Q

What is a biofuel?

A

A fuel obtained from living or recently living organisms

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7
Q

What type of energy source are biofuels?

A

Renewable

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8
Q

Where does the energy required to drive the turbines/produce steam come from in a nuclear power station?

A

Not from burning uranium/plutionium!

  • The nucleaus of a uranium atom can undergo nuclear fission, releasing thermal energy (and other waste energy)
  • There are lots of uranium nuclei, so lots of fission reactions take place, releasing lots of energy
  • This energy is used to heat water, turning it into steam which drives the turbine
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9
Q

Complete the sentence:

Biofuels can be used in…

A

…small-cale, gas-fired power stations

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10
Q

Which releases more energy per kilogram of fuel burnt:

Uranium undergoing fission OR fossil fuels being burnt?

A

Uranium undergoing fission - it has a higher fuel density per kg

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11
Q

Nuclear power stations do not release any…

A

…greenhouse gasses, unlike fossil-fuel power stations

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12
Q

What do nuclear power stations produce that other power stations don’t?

A

Radioactive waste

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13
Q

What are the negatives of radioactive waste

A
  • It’s radioactive
  • It must be safely stored for a long period of time
  • It can be used to make nukes (which can be bad… depening on your views)
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14
Q

Draw and label a diagram of a fossil-fuel powered power station

A
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15
Q

Define ‘renewable energy’

A

Energy from sources that never run out (or will run out in a very, very long time)

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16
Q

How can wind be used to generate electricity?

A
  • Can be used to drive turbines directly
  • In a wind turbine, the wind passing over the blades makes them rotate and drives a generator at the top of a narrow tower
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17
Q

What methods of generating electricity use water?

A

Electricity can be produced from energy obtained from:

  • Falling water - HEP
  • Waves - Wave power
  • Tides - Tidal power
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18
Q

How does HEP work?

A
  • At a HEP, water is collected in a reservoir.
  • This water is allowed to flow downhill and turn turn turbines at the bottom of the hill
  • In a pumped storage system, surplus electricity is used at times of low demand to pump the water back up the hill into the reservoir
  • This means the energy is stored
  • At times of high demand, the water can be released to fall through the turbines and transfer the stored grav. pot. to kinetic, and then to electical energy.
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19
Q

How is wave power used to generate electricity?

A
  • We can use the movement of the waves on the sea to generate electricity
  • The movement drives a floating turbine that turns a generator.
  • Then, the electricity is delivered to the grid system on shore by a cable
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20
Q

How is tidal power used to generate electricity?

A
  • The level of sea around the coastline rises and falls twice each day
  • These changes in sea level are called tides (crazy)
  • If a barrage is built across a river estuary, the water at each high tide can be trapped behind it
  • When the water is released to fall down to the lower sea lever, it drives turbines.

N.B. This works a bit like HEP, except instead of pumping/releasing water from a reservoir, the tides naturally raise the water level and it can then be released.

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21
Q

Why is wave power likely to be less reliable than tidal power?

A

There will always be two tides a day because the tides are controlled by the Sun and Moon.

However, the waves are controlled by the wind and weather, so on a calm day there might not be as many waves.

22
Q

How does solar energy travel from the Sun to the Earth?

A

As electromagnetic radiation (the electromagnetic spectrum)

23
Q

What do solar cells do?

A

Transfer solar energy directly into electricity

24
Q

What are solar cells used to power and why?

A

Only small devices such as watches and calculators because each cell only produces a small amount of energy.

However, we can join large numbers of cells together to form a solar panel.

25
Q

What happens to water flowing through a solar heating panel?

A

It is heated directly by energy from the Sun

26
Q

What is a solar power tower?

A

A tower surrounded by mirrors that reflect sunlight onto a water tank at the top of the tower. This produces steam

27
Q

Draw a labelled diagram of a solar heating panel

A

Rememember to label the black cover!

28
Q

How is geothermal energy used to generate electrictity?

A
  • Geothermal energy is produced inside the Earth by radioactive processes which heat the surrounding rock
  • In volcanic and other suitable areas, very deep holes are drilled and cold water is pumped down to the hot rocks
  • There it is heated and comes back to the surface as steam
  • The steam is then used to drive turbines that turn generators, which in turn produce electricity
  • In some parts of the world, hot water comes up to the surface naturally and can be used to heat buildings near by
29
Q

Which energy resources are non-renewable?

A

Fossil-fuels and nuclear power

30
Q

When will fossil-fuels run out?

A

Oil + gas in the next 50 years, although coal much longer

31
Q

What ways are scientists investigating in order to reduce the environmental impact of using fossil fuels?

A
  • Removing sulfur before burning to prevent sulfur dioxide being produced
  • Carbon-capture/re-capture technology to capture CO2 before it is released into the atmosphere from power stations. It would instead be stored in old oil + gas fields
32
Q

What are the advantages and disadvantages of using coal as an energy source?

A
  • Bigger reserves than other fossil fuels
  • Reliable

HOWEVER

  • Non-renewable
  • Produces CO2, a greenhouse gas (contributes to climate change)
  • Produces SO2, causing acid rain
33
Q

What are the advantages and disadvantages of using oil as an energy source?

A
  • Reliable
  • Already have the infrastructure to burn it

HOWEVER:

  • Non-renewable
  • Produces CO2, a greenhouse gas (contributes to global warming)
  • Produces SO2, causing acid rain
34
Q

What are the advantages and disadvantages of using gas as an energy source?

A
  • Reliable
  • Quick start-up time
  • Existing infrastructure

HOWEVER:

  • Non-renewable
  • Produces CO2, a greenhouse gas (causes climate change)
35
Q

What are the advantages and disadvantages of using nuclear fuel as an energy source?

A
  • No polluting gasses produced
  • Reliable
  • High energy denisty (energy produced per kg fuel)

HOWEVER:

  • Non-renewable
  • Produces radioactive waste, which is difficult to dispose of + must be stored for a long time (long half-life)
  • Small risk of big nuclear accident
  • Slowest start-up time
36
Q

What are the advantages and disadvantages of using wind as an energy source?

A
  • Renewable
  • No polluting gasses produced
  • Free

HOWEVER:

  • Requires many large turbines - unsightly
  • No existing infrastructure
  • Not reliable
37
Q

What are the advantages and disadvantages of using HEP as an energy source?

A
  • Renewable
  • No polluting gasses produced
  • Reliable in wet areas
  • Free

HOWEVER:

  • Only works in wet + hilly areas
  • Damming areas causes flooding and affects local ecology
38
Q

What are the advantages and disadvantages of using waves as an energy source?

A
  • Renewable
  • No polluting gasses produced
  • Free

HOWEVER:

  • Can be hazardous to boats/fish
  • Not reliable
  • No existing infrastructure
39
Q

What are the advantages and disadvantages of using tidal power as an energy source?

A
  • Renewable
  • No polluting gasses produced
  • Free

HOWEVER:

  • Only a few river estuaries suitable
  • Building a barrage affects local ecology + shipping
  • No exisiting infrastructure
40
Q

What are the advantages and disadvantages of using solar power as an energy source?

A
  • Renewable
  • No polluting gasses produced
  • Reliable in hot countries during the day
  • Free

HOWEVER:

  • Solar cells only produce small amounts of electricity
  • Unreliable in less sunny countries
41
Q

What are the advantages and disadvantages of using geothermal power as an energy source?

A
  • Renewable
  • No polluting gasses produced
  • Free

HOWEVER:

  • Only economically viable in a few places
  • Drilling through large depth of rock is difficult + expensive
  • Can also permanently alter local landscape
42
Q

In Britain, how is energy distributed?

A

Through the National Grid

43
Q

What is the National Grid?

A

The network of cables and transformers used to transfer electricity from power stations to consumers

44
Q

What types of pylons are used in different areas?

A

Overhead are used in the countryside

Underground are used in towns and close to homes

45
Q

What is the voltage of the National Grid and of power stations?

A

National Grid: 132,000V +

Power stations: 25,000V

46
Q

How does the National Grid transport energy from power stations to our homes/consumers?

A
  • In power stations, electricity is generated at a particular voltage
  • The volatge is then increased by step-up transformers before being transmitted across the National Grid in cables. This is done because high voltage reduces the energy wasted in cables, making the system more efficient
  • It would be dangerous to supply electricity to consumers at these high voltages, so step-down transformers are used to reduce to voltage to 230V
47
Q

What is the base load?

A

The constant amount of electricity being generated by power stations

48
Q

Complete the sentence:

The demand for electricity varies…

A

…during the day and between summer and winter

49
Q

How can the variable demand for electricity be met?

A
  • Gas-fired power stations can be used because they have a quick start-up time
  • Pumped-storage can be used. When demand is low, water can be pumped to the top of reservoirs ready to be released when deman increases
  • Renewable sources can be used to suppliment the base load (e.g. turning on wind turbines)
50
Q

What percentage of different energy sources does the UK use to generate electricity?

A

46% Gas

31% Coal

16% Nuclear

5% Other fuels + Renewables

1% Oil

1% HEP

51
Q

What types of energy sources are likely to be used in the future to generate electricity?

A
  • Nuclear power stations
  • Fossil-fuel stations using carbon capture
  • Renewable sources
52
Q
A

GCSE Physics (P1) (6 decks)

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