1

Applied Single Award & Entry LevelWJEC ‘Entry Level’ taught in conjunction with content from

Applied Single Award Science – to allow access to WJEC Double Award Science GCSE.

Applied Context: This topic explores different ways of generating electricity and compares them for cost efficiency, reliability and environmental impact. Learners will also explore how electricity can be transferred from power stations to where it is used. Learners can apply their knowledge in a number of fields including electricity generation and sustainable development.

Name: _______________________________________Class: ________________________________________ Teacher: _____________________________________

Please note:

Some of the tasks and questions that you are expected to complete will not be in this booklet.

You will need to bring the following to each of your lessons:

exercise book pen, pencil, ruler, rubber and calculator.

1.1.2 ‘Generating Electricity

Subject Specific Targets 1.1.2 Single Applied

BEFORE Unit

I have LEARNE

D

I understand the advantages and disadvantages of renewable energy technologies (e.g. hydroelectric, wind power, wave power, tidal power, waste, crops, solar and wood) as a means of generating electricity on a national scale using secondary information.I can consider economic, environmental and sustainability issues as well as generating capacities and start-up time.I understand the cost effectiveness of introducing domestic solar and wind energy equipment, including fuel cost savings and payback time by using data.I can consider the reliability of output supply and the potential for meeting a household’s demand.I can comment on sustainability, carbon footprint, cost, reliability, environmental impact to compare different methods of power generation e.g. use data to assess their impact on the environment by considering atmospheric effects (acid rain and carbon dioxide emission), pollution including visual and noise pollution. Including output reliability and ability to meet domestic demand.I understand the lifetime and the useful power produced by renewable energy devices and power stations e.g. solar cell, fuel cell, wind turbines and water turbines.I understand the need for the National Grid as an electricity distribution system including monitoring power use and responding to changing demand.I can recognise the term base load. The role of different types of power stations in responding to changes in demand i.e. start-up times. Understand how the National Grid makes electricity supply more reliable. Recognise power stations, transformers, transmission lines and consumers on a diagram. Interpret graphs of demand through a time period. Importing and exporting of electricity to other European countries.I understand the advantages and disadvantages of using different voltages of electricity at different points in the National Grid to include transmission of electricity and use in the home.I know the use of transformers in the transmission of electricity from the power station to the user in qualitative terms (they should be treated as voltage changers without any reference to how they perform this function).I know Step up transformers increase voltage and decrease current – reduces energy losses in transmission lines making distribution more efficient. Step down transformers reduce voltage to safer levels for consumers. I understand the use of transformers in the transmission of electricity from the power station to the user in qualitative terms (they should be treated as voltage changers without any reference to how they perform this function).I understand the efficiency, reliability, carbon footprint and output to compare different types of power stations in the UK including those fuelled by fossil fuels, nuclear fuel and renewable sources of energy.SPECIFIED PRACTICAL WORK • Investigation of the factors affecting the output from a solar panel

2

Target Sheet: (dual) Applied Single Award & Entry Level WJEC

Single Award = 1.1.2 “Generating Electricity”Entry Level = 1.1.2 “Generating Electricity”

Subject Specific Targets 1.1.2 Entry Level BEFORE Unit

I have LEARNE

DI know about the advantages and disadvantages of renewable and non-renewable energy technologies (e.g. hydro-electrical, wind power, wave power, tidal power, waste, crops, solar and wood, coal, crude oil, natural gas nuclear) as a means of generating electricity on a national scale using secondary information.I have considered economic, environmental and sustainability issues, as well as generating capacities and start-up time.I understand about the cost-effectiveness of introducing domestic solar and wind energy equipment, including fuel-cost savings and payback time by using data.I am able to consider the reliability of output supply and the potential for meeting a household's demand.I know about sustainability, carbon footprint, cost, reliability, environmental impact to compare different methods of power generation.I have learned about output reliability and ability to meet domestic demand.I understand the need for the National Grid as an electricity distribution system including monitoring power use and responding to changing demand.I understand how the National grid makes energy supply more reliable.I know that domestic electricity meters measure the energy used.I am able to interpret data from domestic electricity meters.

Electricity is a clean and convenient form of energy. Task: How have you used electricity in the past 24 hours?

3

My personal target is to: -

I will achieve this by: -

Responding to demandElectricity cannot be stored; it has to be generated from sources as it is needed. In Britain, it is the job of the National Grid to balance the supply and demand of electricity. Demand varies greatly during the day, and throughout the year. Demand will depend upon what people are doing at any point in the day, how cold it is, even whether there is a big sporting event on television.

The grid controllers need to ensure that sufficient power stations are up and running, ready to meet any increase in demand. This makes forward planning important.Since electrical power cannot be stored in large quantities most fossil fuelled and nuclear power stations are run continuously, to provide a minimum amount of power to the National Grid. This is called the base load. In order to respond to changes the National Grid can draw on different sources of power but each source has a different start up time, reliability and cost; they also have a different carbon impact.The most flexible generation is known as ‘pumped storage’. Pumped storage works in a similar way to hydroelectricity but uses electricity at times of low demand to pump water up into a reservoir. This water can then be used to generate electricity at times of high demand. This method of generating electricity is limited so it has to be used along with coal and gas fired power stations. The least flexible is nuclear and the least predictable is wind. The start-up time and carbon footprint of some different forms of electricity are shown below:

The National Grid uses different sources of energy (Non-Renewable and Renewable) in order to ensure that there is an uninterrupted supply of electricity. The UK also has agreements with some other countries which allows for the import or export of electricity when necessary.The world’s population needs energy. The demand for electrical energy is growing. NON-RENEWABLE ENERGY RESOURCES

4

Before the 1990s almost all energy was produced using non-renewable energy sources such as coal, oil and gas. These are known as fossil fuels.

Fuel Where does it come from?

Advantages Disadvantages Sustainability

Coal Formed from dead animals and plants over millions of years.Mined from layers formed between layers of other rock.

Once mined the fuel is ready to burn to produce heat and electricity.It is cheap to mine and to convert into energy.Concentrated source of energy.

When burned coal gives off CO2 which is a greenhouse gas and leads to ‘global warming’.Soot which leads to global dimming.SO2 causing acid rain.

Coal will eventually run out run out. However, coal supplies will last longer than oil or gas.

Oil A black liquid formed from dead animals and plants over millions of years.Large pools of oil are found between layers of rock.Drilling down to the pools allows pipes to be inserted to pump the oil out.

Commonly used in industry and transport.Oil is a readymade fuel.Relatively cheap to extract and to convert into energy.Concentrated source of energy.

When burned coal gives off CO2 which is a greenhouse gas and leads to ‘global warming’.Soot which leads to global dimming.

Oil will run out eventually. Some people estimate that there is only enough oil left to last another 50 years!

Natural Gas

Gases are trapped between layers of rock under the Earth’s surface.Pipes are drilled into the ground to get the gas.

Commonly used in houses for heating and cooking. Gas is a readymade fuel.It is a relatively cheap form of energy.It is a slightly cleaner fuel than coal and oil.Concentrated source of energy.

CO2 which is a greenhouse gas and leads to ‘global warming’.

Gas will eventually run out.

Nuclear Radioactive minerals such as uranium are mined.Electricity is generated from the energy that is released when the atoms of these minerals are split (by nuclear fission) in nuclear reactors.

A small amount of radioactive material produces a lot of energy.Raw materials are relatively cheap and can last quite a long time.It doesn’t give off air pollution.

Nuclear reactors are expensive to run.Nuclear waste is very dangerous and very toxic. The waste needs to be safely stored for hundreds or thousands of years.Storage of nuclear waste is very expensive.Leakage of nuclear materials can have a huge impact on people and the environment.

Nuclear material won’t last forever.

5

6

7

Tasks: (i) Name the fossil fuels.(ii) What are the Non-renewable sources of energy?(iii) Which non-renewable power station has the fastest start-up time?(iv) Which non-renewable has the slowest start up time?(v) What is the effect on our environment by releasing ‘Soot’?(vi) What is the effect of releasing SO2 on our environment?(vii) What is the environmental impact of releasing CO2? (Full detail required).

(viii) What is ‘carbon footprint’?(ix) What is ‘sustainability’(x) You work for the local council planning department and must give

approval for a ‘Non-renewable’ power station. Which one will you choose? (Give as much detail as possible).

(xi) You work for the Welsh Assembly Government and have been advised that you can only give planning permission for ‘Renewable’ power stations. Which 2 sources of renewable energy will you choose for Wales? Why?

Generating electricity from non-renewable sources

Most of the electricity generated in the UK still comes from power stations which burn fossil fuels (coal, oil and natural gas). Nuclear power also makes an important contribution. The pie charts below compare the sources from which electricity was generated in the second quarter of 2014 and 2015.The pie charts show that there is a move away from using coal which has a high carbon footprint. The UK government has committed itself to close all coal-fired power plants by 2025, the first major country to do so. It intends to fill the capacity gap largely with new gas and nuclear plants.

RENEWABLE ENERGY RESOURCES8

Fuel Where does it come from?

Advantages Disadvantages Sustainability

Biomass Biomass energy comes from decaying plant or animal waste.It can also be an organic material which is burned to provide energy.

It is a cheap and readily available source of energy.

When burned coal gives off CO2 which is a greenhouse gas and leads to ‘global warming’.

If the crops are replanted, biomass can be a long-term, sustainable energy source.If crops are not replanted, biomass is a non-renewable resource.

Wood Comes from trees which are burned to generate heat and light.

A cheap and readily available source of energy.

When burned coal gives off CO2 which is a greenhouse gas and leads to ‘global warming’.Soot which leads to global dimming.

If the trees are re-planted, wood burning can be a long-term, sustainable energy source.If trees are not replanted wood is a non-renewable resource.

Hydro-electricPower(HEP)

Hydro-electric energy comes from water being used to turn turbines.Common types of hydro-electric generators are found at dams, using the flow of a river or using the tides of the sea.

A cheap and readily available source of energy.Hydro-electric power stations can be built quite quickly. There is no pollution.

Large reservoirs are required for the operation of conventional hydroelectric dams. This results in submersion of extensive areas upstream of the dam.

This is an energy source which will always exist as long as there is water.

Wave Energy The up and down motion of the waves is caused by the wind.

Renewable.Does not use up fuel.There is no air pollution.

Unreliable (only works when you have suitable waves).Large numbers of wave generators would be needed to generate significant amounts of energy.

This is an energy source which will always exist as long as there is wind to produce the waves.

Tidal Tides are caused by the gravitational pull of the Moon (and Sun).

Renewable. Very Predictable.

Tidal barrages would cause large scale flooding of estuaries, destroying habitats.Huge construction cost.

Highly sustainable.

Wind Power Wind power is the use of airflow through wind turbines to power generators to produce electricity.

There is no pollution.

The force of the wind is not always the same.Wind turbines are noisy.Many people see large wind turbines as unsightly structures.

This is an source which will always exist as long as there is wind.

Solar This is when the light and heat from the Sun is used to

There is no pollution.

Solar power is weather dependent. It does not work at

Solar energy is a truly renewable energy source.

9

generate electricity. night.Storage of solar power is very expensive.

It can be harnessed in all areas of the world and is available every day. We cannot run out of solar energy.

Geothermal Hot water from the radioactive decay of rocks heats water.

Renewable.No pollution.Reliable.Cheap.

Hot springs and rocks are only found in some areas.Ground-source heat pumps need a large area to capture the heat.

Sustainable, but only in some suitable areas of the world.

Specified Practical

10

THE NATIONAL GRID11

Electricity for our homes and places of work is generated by power stations. It gets to consumers through the National Grid. This allows power stations far away to be used to generate our electricity. It also allows different energy resources to be used to supply the country’s electricity. The National Grid is a network that connects all generators of electricity, such as power stations, with all users, such as homes, offices and factories. Power lines across the country connect together all the power stations with all the people who use electricity.

Power stations generate alternating current (a.c.) because:

It is easier to generate Transformers only work with alternating current.

Transporting electricity efficientlyWhenever a current flows through a wire some of the energy is lost as heat. The higher the current, the more heat is lost. In order to reduce these losses, the National Grid transmits electricity at a low current and a high voltage.Power stations produce electricity at 25000V. Electricity is sent through the National Grid cables at 400000V, 275000V and 132000V.TRANSFORMERS

Transformers are used to change the size of the voltage. Step-up transformers are used at power stations to produce the very high voltages needed to transmit electricity through the National Grid power lines (transmission lines).

12

Transformers may look like this.

You might have heard their ‘characteristic humming noise’?

These high voltages are too dangerous to use in the home, so step-down transformers are used locally to reduce the voltage to safe levels.

The voltage of household electricity is about 230V.Electricity is transferred from power stations to consumers through the wires and cables of the National Grid. When electricity flows through a wire some energy is lost as heat. The higher the current, the more heat is lost. To reduce these losses, the National Grid transmits electricity at a low current. This needs a high voltage.A transformer is an electrical device that changes the voltage of an alternating current (ac) supply, such as the mains electricity supply. A transformer that:• Increases the voltage is called a step-up transformer • Decreases the voltage is called a step-down transformer.

Tasks: 1. Make a list of ‘transformers’ in your home.2. Draw a simple step-up transformer. What does it do?3. Give a full written description of the National Grid.4. Draw a full page diagram of the national grid.5. What noise does a transformer make? 6. Do you have any transformers in your house? How many can you name?

7. Complete this simple flow chart to show the stages of making electricity in a fuel based power station. Please note, the energy needed to boil the water comes from fossil fuels or nuclear fuels. Renewable energy resources such as wind and wave power may drive the generators directly.

13

Fuel is burned to boil ________ to make _________.

The steam makes a t____________ spin.

Chemical to Thermal

Increases voltage Decreases voltage

14

The spinning turbine causes a m_________ and c_____ to move and generates electricity.

Thermal to Kinetic

Kinetic to Electrical

15

16

Past paper questions

17

18

1.

2.

Explain the purpose of transformer A ____________________________________Explain the purpose of transformer B ____________________________________

3.

19

4.

20

5.

21