Energy Resources (Edexcel GCSE Physics): Revision Note
Exam code: 1PH0
Energy Resources
Energy resources are large stores of energy that can be used to generate electricity and heat homes and businesses
Some electricity drawn from the National Grid is generated from non-renewable resources, and some is generated from renewable resources
Renewable energy resources
A renewable energy resource is defined as
An energy source that is replenished at a faster rate than the rate at which it is being used
As a result of this, a renewable energy resource is one that will not run out
Renewable resources include:
Solar energy
Wind
Bio-fuel
Hydroelectricity
Geothermal
Tidal
Non-renewable energy resources
Non-renewable energy resources include:
Fossil Fuels (coal, oil and natural gas)
Nuclear fuel
Coal, oil, and natural gas are all examples of fossil fuels, a non-renewable energy resource, which means they will eventually run out
Electricity is generated in very similar ways, no matter what energy resource is used
A turbine is turned, which turns a generator, which generates electricity
The element that differs is how the turbine is made to turn
Energy from water
Water can be used to turn turbines in the case of hydroelectric dams, tidal barrages and tidal turbines
Energy in the kinetic store of the flowing water is transferred to the kinetic store of the turbine and then to the kinetic store of the generator, and transferred electrically to the National Grid
Hydroelectric dam
A hydroelectric dam transfers energy from the gravitational potential energy store of the water to its kinetic energy store mechanically to turn a turbine
Energy from fossil fuels
Fossil fuels can be combusted to heat water, and the steam produced can be used to turn turbines
Energy from the chemical store of the fuel is transferred to the thermal store of the water, which is then transferred to the kinetic store of the turbine, and then transferred to the kinetic store of the generator and then transferred electrically to the National Grid
The energy transfers involved in the production of electricity from fossil fuels
Energy from nuclear fuel
Nuclear fuel can also be used to heat water to produce steam to turn turbines
The energy transfers involved in electricity generation from a nuclear power plant are:
Nuclear store of fuel → thermal store of water → kinetic store of turbine → kinetic store of generator
Energy from geothermal sources
Geothermal energy is another way to produce the steam that turns the turbines
Water is pumped down to the hot rocks and returns through a fissure as steam
Cold water is heated by the rocks and returned as hot water or steam which can be used to turn turbines to generate electricity
Summary of energy resources
Generating energy reliably requires the use of a range of different energy resources, as listed in the table below:
Energy resources table
Energy resources | Description |
|---|---|
Fossil fuels | Fossil fuels are combusted to heat water to produce steam to turn turbines to generate electricity |
Nuclear | Nuclear fuels undergo fission to heat water to produce steam to turn turbines to generate electricity |
Bio-fuels | Plant matter, ethanol or methane can be produced and used as a fuel in place of fossil fuels |
Wind | Wind turns turbines directly to generate electricity |
Hydroelectric | Water is stored at a height and, when released, the rushing water turns turbines directly to generate electricity |
Tidal | The movement of water due to tides turns turbines directly to generate electricity |
Geothermal | Hot rocks underground are used to heat water to produce steam to turn turbines to generate electricity |
Solar | Solar cells (photovoltaic panels) use light to generate electricity. Solar heating panels use thermal radiation to heat water for household use |
Water waves | Moving water due to waves turns turbines directly to generate electricity |
Worked Example
Electricity can be generated by wind power. Describe the energy transfers which occur when a wind turbine is used to generate electricity for the National Grid.
Answer:
Step 1: Determine where the energy is transferred from
Energy is transferred from the kinetic store of the moving wind...
Step 2: Determine the energy transfer involved as energy is transferred from the wind to the turbine
...to the kinetic store of the turbine as the wind makes it turn.
Step 3: Name the other energy transfers that occur in the process of generating electricity
Energy is transferred from the kinetic store of the turbine to the kinetic store of the generator and is transferred electrically to the National Grid.
Comparing Energy Resources
Advantages and disadvantages of energy resources
Each energy resource has various advantages and disadvantages associated with it
A renewable energy resource is one that is replenished as it is used
A non-renewable energy resource is one that is finite (there is a limited supply)
A reliable energy resource is one that can produce energy at any time
Non-reliable resources can only produce energy some of the time (e.g. when it’s windy)
The table below shows a comparison of the advantages and disadvantages of the different energy resources:
Table comparing advantages and disadvantages of energy resources
Energy resource | Renewable? | Advantages | Disadvantages |
|---|---|---|---|
Fossil fuels | No | Reliable. Can produce large amounts of energy consistently. Can respond to changes in demand. | Produces carbon dioxide (CO2), which contributes to global warming, and sulphur dioxide, which causes acid rain |
Nuclear | No | Reliable. Produces large amounts of energy consistently. Produces no pollution or CO2. Large amounts of energy are produced from small amounts of fuel. | Produces radioactive waste that takes thousands of years to decay and must be safely disposed of. Nuclear power stations are expensive to build and maintain, and take many years to build. Can not be turned on and off quickly, so cannot respond to changes in demand. |
Bio fuels | Yes | The CO2 released from combustion is balanced by the CO2 absorbed in photosynthesis, so it could be considered carbon neutral | Land and resources used to grow crops are needed to grow food crops |
Wind | Yes | Produces no pollution or CO2. Are cheap to build and maintain | Non-reliable. Only generates electricity when the wind is blowing in a certain direction. Some people consider them visual pollution (they spoil the view) |
Hydroelectric | Yes | Reliable. Can respond to meet changes in demand. No pollution or CO2 produced (unless a pump is used to return the water, as this uses fossil fuels). | Can involve flooding large areas to build reservoirs, which destroys habitats and displaces wildlife |
Tidal | Yes | Tides are very predictable, so energy can be produced at regular intervals | Few suitable locations (estuaries). Can harm aquatic life and disrupt shipping |
Geothermal | Yes | Reliable | Not many suitable locations. Can release methane (a greenhouse gas) in the extraction process. |
Solar | Yes | Produces no pollution or greenhouse gases. Good for electricity production in remote areas. | Non-reliable. Only generates electricity when the Sun is shining. Each solar cell only produces a small amount of electricity, so many cells are needed. |
Examiner Tips and Tricks
Make sure you're familiar with the advantages and disadvantages of large-scale electricity production from renewable and non-renewable energy sources, as this is a common exam question.
In a compare question, make a comparative statement about the same factor for both resources, for example: the wind turbine is larger, but harms birds; the tidal turbine harms fish but does not cause visual pollution.
If the question asks for environmental impact, do not write about reliability, efficiency or cost.
The Use of Energy Resources
The three main uses of energy resources include:
Transport
Electricity generation
Heating
Types of energy resources
Transport
The majority of vehicles in the world are powered by petroleum products such as petrol, diesel and kerosene
These resources all originate from crude oil, which is a fossil fuel
A growing number of vehicles are now being powered by electricity
The advantage of this is that while the vehicle is being driven, it produces zero carbon emissions
The disadvantage is that when the vehicle is being charged, it is connected to the National Grid, which currently uses a combination of renewable and non-renewable energy sources
Vehicles can also be powered by biofuel
The advantage of biofuel is that it is a renewable resource
However, the claim that biofuels are carbon-neutral is largely controversial
Electricity generation
Electricity plays a bigger role in people's lives than ever before
With over 8 billion people in the world, this means the demand for electricity is extremely high
To keep up with this demand, a combination of all the energy resources available is needed
On the downside, the majority (84%) of the world's energy is still produced by non-renewable, carbon-emitting sources
This has an enormous negative impact on the environment
Currently, scientists are working hard to develop more and more efficient ways to produce electricity using more carbon-neutral energy resources
Pie chart of global energy consumption
Heating
Most homes in cold countries are fitted with central heating systems
These utilise natural gas in order to heat up water, which can be pumped around radiators throughout the home
Unfortunately, gas is a non-renewable energy resource
In geologically active countries, such as Iceland, they are fortunate to be able to heat their homes using geothermal energy
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