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1.3 National and global energy resources - High demand – Questions
Q1.All European Union countries are expected to generate 20% of their electricity using renewable energy sources by 2020.
The estimated cost of generating electricity in the year 2020 using different energy sources is shown in Table 1.
Table 1
Energy source Estimated cost (in the year 2020) in pence per kWh
Nuclear 7.8
Solar 25.3
Tidal 18.8
Wind 10.0
France generated 542 billion kWh of electricity using nuclear power stations in 2011.France used 478 billion kWh of electricity and sold the rest of the electricity to other countries in 2011.
(a) France may continue generating large amounts of electricity using nuclear power stations instead of using renewable energy resources.
Suggest two reasons why.
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(b) Give two disadvantages of generating electricity using nuclear power stations.
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(c) A panel of solar cells has an efficiency of 0.15.
The total power input to the panel of solar cells is 3.2 kW.
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Calculate the useful power output of this panel of solar cells in kW.
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Useful power output = _______________ kW(2)
(d) Table 2 shows the manufacturing cost and efficiency of different types of panels of solar cells.
Table 2
Type of Solar Panel Cost to manufacture a 1 m2 solar panel in £ Efficiency in %
A 40.00 20
B 22.50 15
C 5.00 10
Some scientists think that having a low manufacturing cost is more important than improving the efficiency of solar cells.
Use information from Table 2 to suggest why.
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(Total 8 marks)
Q2.Electricity in the UK is generated in many ways.
The figure below shows an undersea turbine.
The undersea turbine uses tidal energy to generate electricity.
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© alex-mit/iStock/Thinkstock
(a) What is the original source of energy for tidal power schemes?
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(b) Explain two advantages of using undersea tidal turbines to generate electricity rather than burning fossil fuels.
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(c) Some power stations burn wood instead of fossil fuels to generate electricity.
A coal-burning power station burns 6 million tonnes of coal per year.
Coal has an average energy value of 29.25 MJ per kg.
Wood chip from willow trees has an energy value of 13 MJ per kg.
A hectare of agricultural land can produce 9 tonnes of dry willow wood per year.
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If this power station burned dry willow wood instead of coal, how much agricultural land would be needed to grow the willow?
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Amount of land needed = _____________ hectares(3)
(d) The table below shows the carbon dioxide emissions of four fuels used to generate electricity.
Fuel Direct CO2 emissionsin kg per MWh
Lifecycle CO2
emissionsin kg per MWh
Coal 460 540
Natural gas 185 215
Oil 264 313
Wood 2 100 58
Direct CO2 emissions are the amounts of carbon dioxide released when the fuel is burned.
Lifecycle CO2 emissions is the total amount of carbon dioxide released during all stages from fuel extraction to when the fuel has been used.
Use the data from the table above to explain why wood is considered to be a low carbon dioxide emitting fuel.
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(Total 10 marks)
Q3.
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On 7th June 2017 more than 50% of the electricity generated in the UK was from renewable sources.
(a) Suggest two environmental conditions in the UK on 7th June 2017.
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2. _________________________________________________________________
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(b) At midday 35.4 GW of electricity was generated.
20.8% of this was provided by gas-fired power plants.
Calculate the energy per second that was provided by gas-fired power stations.
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Energy per second = ____________________ J(3)
(c) Some of the electricity generated was from low-carbon sources.
Low-carbon sources emit very little carbon dioxide.
Name one non-renewable resource that is a low-carbon source.
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(d) In the UK, electricity is delivered to consumers by the National Grid.
Explain the main features of the National Grid.
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(e) The National Grid supplied a house with 18 000 000 J of energy in 1 hour.
What was the average current supplied to the house during that hour?
Write any equations that you use.
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Current = ____________________ A(5)
(Total 17 marks)
Q4.The image below shows a solar thermal power station that has been built in a hot desert.
The power station uses energy from the Sun to heat water to generate electricity.
Energy from the Sun is reflected towards a solar receiver using many mirrors.
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© Kim Steele/Photodisc/Thinkstock
(a) (i) Which part of the electromagnetic spectrum provides most of the energy to heat the water in a solar thermal power station?
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(ii) Describe how heated water is used to generate electricity by thissolar thermal power station.The process is the same as in a fossil fuel power station.
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(b) A new type of solar power station, called a solar storage power station, is able to store energy from the Sun by heating molten chemical salts.The stored energy can be used to generate electricity at night.
(i) It is important that the molten chemical salts have a high specific heat capacity.Suggest one reason why.
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(ii) The solar storage power station can store a maximum of 2 200 000 kWh of energy.The solar storage power station can supply a town with a maximum electrical power of 140 000 kW.
Calculate for how many hours the energy stored by the solar storage power station can supply the town with electrical power.
Give your answer to 2 significant figures.
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Time = __________________ hours(3)
(iii) Table 1 gives information about the place where the solar storage power station has been built.
Table 1
Season Mean number ofdaylight hours
Mean power received fromthe Sun per
square metre in kW
Spring 11.5 0.90
Summer 13.5 1.10
Autumn 12.0 0.95
Winter 10.5 0.71
The solar storage power station does not operate at the maximum possible electrical output every day of the year.
Suggest why.
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(c) Power stations do not work at maximum possible electrical output all the time.The ‘capacity factor’ of a power station is calculated using the equation:
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Table 2 shows capacity factors for different types of power station.
Table 2
Type of power station
Renewable energysource
Capacity factor
Coal No 0.41
Natural gas No 0.48
Nuclear No 0.66
Solar thermal Yes 0.33
Tidal Yes 0.26
Wind turbine Yes 0.30
(i) Compare the capacity factors of the renewable power stations with those of the non-renewable power stations in Table 2.Explain the reason for the difference between the capacity factors.
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(ii) The capacity factor of a solar storage power station is higher than for all other renewable power stations.Suggest one reason why.
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(Total 14 marks)
Q5.Solar panels are often seen on the roofs of houses.
(a) Describe the action and purpose of a solar panel.
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(b) Photovoltaic cells transfer light energy to electrical energy.
In the UK, some householders have fitted modules containing photovoltaic cells on the roofs of their houses.
Four modules are shown in the diagram.
The electricity company pays the householder for the energy transferred.
The maximum power available from the photovoltaic cells shown in the diagram is 1.4 × 103 W.
How long, in minutes, does it take to transfer 168 kJ of energy?
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___________________________ Time = ____________________ minutes(3)
(c) When the modules are fitted on a roof, the householder gets an extra electricity meter to measure the amount of energy transferred by the photovoltaic cells.
(i) The diagram shows two readings of this electricity meter taken three months apart.The readings are in kilowatt-hours (kWh).
21 November 0 0 0 4 4
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21 February 0 0 1 9 4
Calculate the energy transferred by the photovoltaic cells during this time period.
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Energy transferred = ____________________ kWh(1)
(ii) The electricity company pays 40p for each kWh of energy transferred.
Calculate the money the electricity company would pay the householder.
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Money paid = ____________________(2)
(iii) The cost of the four modules is £6000.
Calculate the payback time in years for the modules.
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Payback time = ____________________ years(3)
(iv) State an assumption you have made in your calculation in part (iii).
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(d) In the northern hemisphere, the modules should always face south for the maximum transfer of energy.
State one other factor that would affect the amount of energy transferred during daylight hours.
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(Total 13 marks)
Q6.(a) In the UK, over 70% of the electricity is generated in power stations that burn fossil
fuels.
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(i) Explain one effect that burning fossil fuels has on the environment.
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(ii) Give one way the effect on the environment described in part (a)(i) could be reduced.
Assume the amount of fossil fuels burnt stays the same.
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(b) Electricity can also be generated in a pumped storage hydroelectric power station.
An advantage of pumped storage hydroelectric power stations is the short start-up time they have.
(i) What is the importance of the short start-up time?
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(ii) Give one other advantage of a pumped storage hydroelectric power station.
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(c) Read the extract below from a newspaper article.
(i) In the UK, the proportion of electricity generated using wind turbines is due to increase a lot. Some opponents of wind turbines think this increase will cause big fluctuations in the electricity supply.
Suggest one reason why this may be true.
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(1)
(ii) Between 2002 and 2008 the amount of electricity used for lighting in homes in the UK decreased.
Suggest one reason why.
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(Total 7 marks)
Q7.About half of the UK’s electricity is generated in coal-burning power stations and nuclear power stations.
(a) Coal-burning power stations and nuclear power stations provide a reliable way of generating electricity.
What is meant by a reliable way of generating electricity?
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(b) Over the next few years, most of the older nuclear power stations in the UK will be closed down, and the process of decommissioning will start.
What does it mean to decommission a nuclear power station?
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(c) Climate change has been strongly linked to the emission of carbon dioxide. Many governments around the world are committed to reducing carbon dioxide emissions.
Generating electricity can increase carbon dioxide emissions.
The companies generating electricity could reduce carbon dioxide emissions.
Give two ways the companies could do this.
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(d) Electricity is distributed from power stations to consumers along the National Grid.
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The voltage across the overhead cables of the National Grid needs to be much higher than the output voltage from the power station generators.
Explain why.
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(Total 7 marks)
Q8.(a) Solar energy is a renewable energy source used to generate electricity.
(i) What is meant by an energy source being renewable?
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(ii) Name two other renewable energy sources used to generate electricity.
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(b) A householder uses panels of solar cells to generate electricity for his home.The solar cells are tilted to receive the maximum energy input from the Sun.
The data in the table gives the average energy input each second (in J/s), to a 1 m2 area of solar cells for different angles of tilt and different months of the year.
Month Angle of tilt
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20° 30° 40° 50°
February 460 500 480 440
April 600 620 610 600
June 710 720 680 640
August 640 660 640 580
October 480 520 500 460
December 400 440 420 410
(i) Use the data in the table to describe how the average energy input to the solar cells depends on the angle of tilt.
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(ii) The total area of the solar cell panels used by the householder is 5 m2.
The efficiency of the solar cells is 0.18.
Calculate the average maximum electrical energy available from the solar cell panels each second in June.
Show clearly how you work out your answer.
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Maximum energy = ________________________ joules/second(3)
(c) The diagram shows part of the National Grid.
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(i) Even though the householder uses solar cells to generate electricity for his home, the home stays connected to the National Grid.
Give one reason why the householder should stay connected to the National Grid.
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(ii) The step-up transformer increases the efficiency of the National Grid.
Explain how.
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(Total 10 marks)
Q9.The world’s biggest offshore wind farm, built off the Kent coast, started generating electricity in September 2010.
(a) The graph shows how wind speed affects the power output from one of the wind turbines.
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In one 4-hour period, the wind turbine transfers 5600 kilowatt-hours of electrical energy.
Use the data in the graph to calculate the average wind speed during this 4-hour period.
Show clearly how you work out your answer.
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Average wind speed = ____________________ m/s(3)
(b) The wind turbines are linked to the National Grid by underwater cables.
(i) What is the National Grid?
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(ii) How is the National Grid designed to reduce energy losses during transmission?
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(c) Read this extract from a newspaper.
Explain one way in which the islanders could try to ensure that a similar power crisis does not happen in the future.
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(Total 7 marks)
Q10.A burger van has a sign on the side.
The company that owns the van makes biodiesel from cooking oil.
A scientist investigated the emissions from biodiesel and petroleum diesel.
The scientist burned the same mass of each fuel in a diesel engine.
The scientist compared the emissions produced.
The results are shown in the table.
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Biodiesel Petroleum diesel
Carbon dioxide emitted in g 3000 3000
Unburnt hydrocarbons emitted in g 7 10
Soot emitted in g 6 12
Nitrogen oxides emitted in g 5 2
Use your scientific knowledge and the data in the table to evaluate the advantages and disadvantages of using biodiesel rather than petroleum diesel as a fuel.
Remember to include a supported conclusion in your answer.
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Q11.A householder wants to reduce his electricity bill by installing a system that uses a renewable energy resource to generate electricity.
The renewable energy systems for generating electricity the householder is considering are:
• a wind turbine
• solar cells.
(a) Suggest which of these systems for generating electricity has the lower maintenance cost.
Give a reason for your answer.
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(b) Using a renewable energy system may save money in the long term.
Suggest a reason why.
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(c) The table shows information about each system used to generate electricity.
Wind turbine Solar cells
Installation cost in £ 1500 9000
Amount of electrical energy generated per year in kWh 1020 1700
Percentage (%) of household requirement that system can generate 30 50
(i) Calculate how much electrical energy the householder needs each year.
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(ii) Using only information from the table, suggest which system the householder should choose.
Support your answer with calculations.
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(Total 6 marks)
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Q12.Nuclear fuels and fossil fuels are non-renewable energy sources.
(a) Power stations generate electrical power.
Describe the similarities and differences between generating power using nuclear fuels and using fossil fuels.
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(b) Figure 1 shows the power generated using different energy sources in the UK.
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(i) Nuclear fuels are less readily available, and more expensive, than fossil fuels.
Suggest two other reasons why nuclear fuels are used less than fossil fuels to generate power.
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(ii) Suggest two reasons why the proportion of power generated using fossil fuels might decrease in the future.
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(c) Figure 2 shows how power is distributed from a power station and transmitted along
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the National Grid.
Explain why step-up transformers are included in the National Grid.
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(d) Shale gas is natural gas trapped in rocks. The shale gas can be extracted by a process called fracking. The shale gas can then be used as a fuel.
Part of a news report on fracking is shown below.
Fracking is a process used to extract shale gas from difficult-to-reach places.Fracking will provide more shale gas, so gas prices may go down. If shale gas was used in power stations, less carbon dioxide would be produced than if coal was used in power stations.
Many possible fracking sites are close to built-up areas. Some local people are opposed to fracking. A lot of water needs to be transported to the fracking site. The process of fracking uses chemicals known to cause cancer and these chemicals may escape and contaminate the water supply. Some local people also worry that fracking may cause small earth tremors. These people say fracking is discouraging energy companies from investing money in renewable sources of energy.
Use information from the news report and your own knowledge to suggest, with reasons, why some local people are opposed to fracking.
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(Total 14 marks)
Q13.Antarctica is a huge land mass surrounding the Earth’s south pole. It is covered in a very thick layer of ice and is the only remaining large area of the Earth’s surface that has not been affected very much by humans.
There are, however, teams of scientists from various countries studying Antarctica. These scientists need electricity for lighting, for their computers and other scientific instruments and to communicate, via satellite, with the rest of the world. The temperature in Antarctica is always sub-zero, so the scientists need some way of keeping their buildings warm. They also need fuel to be able to get around on their snowmobiles.
Scientists cannot avoid affecting the environment. However, they want to affect it as little as possible.
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Atmospheric pollution produced in one country eventually affects the whole of the Earth’s atmosphere. The hole that appears each year in the ozone layer above Antarctica, for example, is mainly caused by pollutants such as CFCs from countries in the northern half of the Earth.
Discuss the advantages and disadvantages of using the following energy sources to meet the scientists’ needs:
• solar energy
• energy from the wind
• natural gas (present in large quantities deep down in the Antarctic land mass)
• diesel oil (which would have to be imported)
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Q14.The bar chart shows the relative costs of some different energy sources that are used to generate electricity.
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(a) Apart from cost, give two advantages that a hydroelectric power station has compared with a wind farm.
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(b) Apart from cost, give one advantage and one disadvantage that a nuclear power station has compared with a coal-fired power station.
Advantage __________________________________________________________
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Disadvantage _______________________________________________________
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(c) State and explain one situation where it is better to use solar energy, rather than any of the other energy sources, to generate electricity.
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(Total 6 marks)
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Q15.Different energy sources are shown in the box.
An ‘Eco-home’ is one which is friendly to the environment.Imagine you are designing an ‘Eco-home’ which can use any of the energy sources above to generate electricity
(a) Choose one non-renewable energy source from the box above that could provide the electricity supply to your ‘Eco-home’, but which would be unsuitable.
Write the energy source in the table and explain, as fully as you can, why it is unsuitable for an ‘Eco-home’.
Non-renewable energy source
Unsuitable for an ‘Eco-home’ because
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(2)
(b) Choose two suitable renewable energy sources from the box opposite that could provide an electricity supply to your ‘Eco-home’.
Write the two energy sources in the table and describe, in as much detail as you can, the undesirable environmental effects of using these.
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Renewable energy source
Undesirable environmental effects
1
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2
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(4)(Total 6 marks)
Q16.Use of renewable sources of energy is expected to increase. The table shows the comparative costs of producing 1 kWh of electricity from different energy sources.
Types of energy sources used in the UK
Cost of producing 1 kWh of electrical energy
Fossil fuels(non-renewable) Coal 1.0 p
Gas 1.4 p
Oil 1.5 p
Nuclearfuels (non-renewable) Nuclear 0.9 p
Renewable Hydroelectric 0.2 p
Wind 0.9 p
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Installation and decommissioning costs are notincluded
At present about 2% of electricity generated in the UK uses renewable energy sources. Consider the three types of energy sources in the table and give one advantage and one disadvantage for each (other than installation and decommissioning costs).
Advantage Disadvantage
Using fossil fuels
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Using fossil fuels
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Using nuclear fuels
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Using nuclear fuels
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Using renewable sources
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Using renewable sources
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(Total 6 marks)
Q17.The map below shows the position of two towns, A and B, on the banks of a large river estuary.
A is an important fishing and ferry port.
The wind usually blows from the west. The major roads and railways are shown.
A power station is to be built in area X to generate electricity for the region.
The choice is between a nuclear power station and a coal fired power station.
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(a) State the advantages and disadvantages of the two methods of generating electrical energy.
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(b) Which method would you choose for this site?
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Explain the reason for your choice.
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(Total 9 marks)
Q18.The diagram below shows four stages in the production of electricity by a coal-fired power station.
(a) (i) Write down two environmental problems which are caused by burning coal to generate electricity.
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2. ____________________________________________________________
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(ii) How may these environmental problems be reduced?
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2. ____________________________________________________________
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(b) Some data for Didcot coal-fired power station is given below.
Number of generators 4Maximum continuous power rating of a generator 500 MW at 23 500 VEnergy content of coal used 2.66 × 1010 J per tonne
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Total quantity of coal used each day 18 289 tonnes
Use the given data to calculate:
(i) the total electrical energy output each day.
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Answer ________________________J/day
(ii) the total input of coal energy each day.
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Answer ________________________J/day
(iii) the efficiency of the power station.
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Answer ________________________ %(8)
(c) Energy is conserved.
(i) Choose one of the stages in the diagram at the start of the question.State what happens to the wasted energy during this stage.
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(ii) Explain what happens to all wasted energy during energy transfers.
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(Total 15 marks)
Q19.
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Transformer A produces a very high voltage to transmit the electrical energy through the National Grid.Explain why electrical energy is transmitted at a very high voltage.
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Q20.Describe, in as much detail as you can, how the energy stored in coal is transferred into electrical energy in a power station.
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Q21.The outline diagram below shows a tidal power generating system.
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Gates in the barrage are open when the tide is coming in and the basin is filling to the high tide level. The gates are then closed as the tide begins to fall.
Once the tide outside the barrage has dropped the water can flow through large turbines in the barrage which drive generators to produce electrical energy.
In one second 1.2 × 109 kg of water flows through the turbines at a speed of 20 m/s.
(a) When used with a water speed of 20 m/s the system has an efficiency of 90% in converting the kinetic energy of the water into electrical energy. Calculate the power output of the generators.
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(b) The power output of a coal fired power station is 1000 MW (1 x 109 W).
(i) Suggest two advantages of coal fired power stations over tidal power generating systems.
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2. ____________________________________________________________
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(ii) Suggest two advantages of tidal power generating systems over coal fired power stations.
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2. ____________________________________________________________
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(iii) Suggest and explain one disadvantage of a tidal power generating system.
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(Total 8 marks)
Q22.The map below shows an industrial region (shaded).
The prevailing wind is from the west. There is a nearby mountainous area, from which a river flows through the region. The major road and rail links are shown.
A power station is to be built to supply electrical energy to the region. The energy will be for a range of domestic and industrial uses.
The choice is between a coal fired power station, wind turbines and a hydroelectric scheme.
Three local groups each support a different option. Choose which option you would
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support and justify your choice by making reference to the financial, social and environmental implications of your choice compared with those of the alternative systems.
(Total 8 marks)
Q23.(a) Most electricity in Britain is generated by coal fired power stations.
Complete the sequence of useful energy transfers which take place in the power station.
(1)
(b) The diagram shows a wind turbine which is used to produce electricity using energy from the wind.
(i) What is the source of energy which creates winds?
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(ii) Explain the advantage of using a wind turbine to produce electricity.
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______________________________________________________________(2)
(Total 4 marks)
Q24.(a) Explain how energy is produced in the Sun.
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___________________________________________________________________(3)
(b) Read the following article that appeared in a magazine.
“Conservation of energy is important in today’s society. Energy sources, such as oil and coal, which have been used for the development of an industrial society, cannot be relied upon as heavily in the future. Renewable energy sources cannot provide such large quantities of energy for society without causing problems.”
(i) Give two reasons why oil should not be relied on as a major source of energy for the future.
1. ____________________________________________________________
______________________________________________________________
2. ____________________________________________________________
______________________________________________________________(2)
(ii) Energy from the wind is a renewable energy resource. State three problems which may arise if the wind were to be used to meet the energy requirements of a large industrial city in Britain.
1. ____________________________________________________________
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2. ____________________________________________________________
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3. ____________________________________________________________
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(3)(Total 8 marks)
Q25.The diagram shows how electricity is distributed from power stations to consumers.
(a) (i) What name is given to the network of cables and transformers that links power stations to consumers?
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(ii) What does a step-up transformer do?
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(iii) Explain why step-up transformers are used in the electricity distribution system.
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(b) Most of the world’s electricity is generated in power stations that burn fossil fuels.
State one environmental problem that burning fossil fuels produces.
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___________________________________________________________________(1)
(c) Electricity can be generated using energy from the wind. A company wants to build a new wind farm. Not everyone thinks that this is a good idea.
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(i) What arguments could the company give to persuade people that a wind farm is a good idea?
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(ii) What reasons may be given by the people who think that wind farms are not a good idea?
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(Total 9 marks)
Q26.There is an increasing demand for electricity and the reserve of fossil fuels is decreasing. A way to meet increasing demand for electricity is to build new nuclear power stations. Some people feel that no new nuclear power stations should be built because of the risks associated with nuclear fuels.
(a) Outline the arguments that a scientist working in the nuclear power industry could use to justify the building of more nuclear power stations in the future.
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___________________________________________________________________
___________________________________________________________________(3)
(b) Nuclear waste is a problem that must be dealt with. One possible solution would be to bury the waste deep underground.
Suggest one reason why some people are against burying nuclear waste.
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___________________________________________________________________(1)
(c) Electricity can also be generated using renewable energy sources.
Look at this information from a newspaper report.
• The energy from burning bio-fuels, such aswoodchip and straw, can be used to generate electricity.
• Plants for bio-fuels use up carbon dioxideas they grow.
• Farmers get grants to grow plants forbio-fuels.
• Electricity generated from bio-fuels can besold at a higher price than electricity generated from burning fossilfuels.
• Growing plants for bio-fuels offers newopportunities for rural communities.
Suggest why, apart from the declining reserves of fossil fuels, power companies should use more bio-fuels and less fossil fuels to generate electricity.
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(Total 7 marks)
Q27.(a) Solar energy is a renewable energy source that can be used to generate electricity.
(i) What is meant by an energy source being renewable?
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______________________________________________________________(1)
(ii) Name two further renewable energy sources used to generate electricity.
1. ____________________________________________________________
2. ____________________________________________________________(1)
(b) A householder uses a bank of solar cells to generate electricity for his home.The solar cells are tilted to receive the maximum energy input from the Sun.
The data in the table gives the average energy input each second (in J/s), to a 1 m2 area of solar cells for different angles of tilt and different months of the year.
MonthAngle of tilt
20° 30° 40° 50°
February 460 500 480 440
April 600 620 610 600
June 710 720 680 640
August 640 660 640 580
October 480 520 500 460
December 400 440 420 410
(i) Use the data in the table to describe how the average energy input to the solar cells depends on the angle of tilt.
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______________________________________________________________(2)
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(ii) The bank of solar cells used by the householder has an area of 8 m2.
The efficiency of the solar cells is 0.15
Calculate the average maximum electrical energy available from the bank of solar cells each second in June.
Show clearly how you work out your answer.
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Maximum energy = _________________________ joules/second(3)
(c) The graph shows how the householder’s electrical energy needs change over one year.
Why would it be advisable for the householder to remain connected to the National Grid?
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(Total 8 marks)
Q28.The pie charts show the relative proportions of electricity generated in Japan from
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different energy sources in 1975 and 2005.
(a) Describe the main differences in the energy sources used in 2005 compared with 1975.
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___________________________________________________________________(1)
(b) In the UK, nuclear fuels are used to generate about 21% of the total electricity supply.
(i) What is the name of the process by which a nuclear fuel produces heat?
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(ii) Explain how the heat released from a nuclear fuel is used to generate electricity in power stations.
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(iii) Some people have suggested that more nuclear power stations should be built in the UK.
Give two reasons to support this suggestion.
1. ____________________________________________________________
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2. ____________________________________________________________
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(iv) Nuclear power stations create dangerous waste.
Why is the waste from a nuclear power station dangerous?
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(c) A headline from a newspaper article is shown below.
Explain the possible link between climate change and coal-burning power stations.
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(Total 9 marks)
Q29.The map shows the positions of two towns on either side of a very large coastal bay in England. The map also shows where a bridge may be built to link the towns. The road journey from one town to the other is about 60 kilometres at present.
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(a) It is estimated that building turbines and generators inside the legs of the bridge would produce enough electricity for both towns. In addition, enough electricity would be generated to run electric buses over the bridge between the two towns.
(i) If the bridge is built, what form of renewable energy will be used to generate the electricity?
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(ii) Most people living in the area are in favour of the proposed bridge.
Suggest three reasons why people would be in favour of building the bridge and the associated electricity generating scheme.
Reason 1 ______________________________________________________
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Reason 2 ______________________________________________________
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Reason 3 ______________________________________________________
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(b) Even with the proposed bridge, the two towns will need to stay connected to the National Grid.
The diagram shows part of the National Grid.
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(i) Give one reason why the towns need to stay connected to the National Grid.
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(ii) Explain how the step-up transformer increases the efficiency of the National Grid.
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(Total 7 marks)
Q30.Over the next 15 years, some of the older nuclear power stations will be closed down, and the process of decommissioning will start. In the same period, several countries plan to build a number of new nuclear power stations.
(a) (i) What does it mean to decommission a nuclear power station?
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(ii) How does decommissioning affect the overall cost of electricity generated using nuclear fuels?
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(b) Uranium is a fuel used in nuclear power stations to generate electricity.
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Graph 1 compares how the electricity generated from one kilogram of nuclear fuel changed between 1980 and 2005 in three different types of nuclear power station.
(i) Compare the efficiency of the three types of power station, K, L and M, between 1980 and 2005.
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Graph 2 shows two different predictions for the global growth in uranium demand over the next few years.
(ii) Suggest reasons why it is not possible to predict accurately how much uranium will be needed in 2025.
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(Total 6 marks)
Q31.(a) The diagram shows a solar powered device being used to recharge a mobile phone.
On average, the solar cells produce 0.6 joules of electrical energy each second.The solar cells have an efficiency of 0.15.
(i) Calculate the average energy input each second to the device.
Show clearly how you work out your answer.
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Average energy input each second = __________________ J/s(2)
(ii) Draw a labelled Sankey diagram for the solar cells.The diagram does not need to be drawn to scale.
(1)
(b) Scientists have developed a new type of solar cell with an efficiency of over 40 %.The efficiency of the solar cell was confirmed independently by other scientists.
Suggest why it was important to confirm the efficiency independently.
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___________________________________________________________________(1)
(c) The electricity used in homes in the UK is normally generated in a fossil fuel power station.
Outline some of the advantages of using solar cells to generate this electricity.
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___________________________________________________________________(2)
(Total 6 marks)
Q32.The diagram shows a small-scale, micro-hydroelectricity generator which uses the energy of falling river water to generate electricity. The water causes a device, called an Archimedean screw, to rotate.The Archimedean screw is linked to the generator by a gearbox.
(a) Each second, the micro-hydroelectricity generator transforms 80 000 joules of gravitational potential energy into 60 000 joules of electrical energy.
(i) Fill in the missing word to complete the energy transformation diagram.
Gravitational potentialenergy of the falling water
________________ energy
of the Archimedean screw
Electrical energygenerated
(1)
(ii) Use the equation in the box to calculate the efficiency of the micro-hydroelectricity generator.
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Show clearly how you work out your answer.
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Efficiency = ______________________________(2)
(b) The power output from a conventional large-scale hydroelectric power station is 100 000 times more than the power output from a micro-hydroelectric system.
Give one disadvantage of a conventional large-scale hydroelectric power station compared to the micro-hydroelectric system.
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(c) The electricity generated by a micro-hydroelectric system is transferred via a transformer directly to local homes. The electricity generated by a conventional large-scale hydroelectric power station is transferred to the National Grid, which distributes the electricity to homes anywhere in the country.
(i) What is the National Grid?
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(ii) Explain why transferring the electricity directly to local homes is more efficient than using the National Grid to distribute the electricity.
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(Total 7 marks)
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