Energy Resources (Edexcel IGCSE Physics)
Revision Note
Energy resources
Energy resources in physics are large stores of energy that can be used to generate electricity and heat homes and businesses
There are sometimes also called energy sources
Renewable and non-renewable energy resources
Some electricity drawn from the National Grid is generated from non-renewable resources, and some is generated from renewable 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 include:
Fossil Fuels (coal, oil and natural gas)
Nuclear fuel
Generating electricity from energy resources
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
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, 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
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
Fossil fuel electricity generation
The energy transfers involved in the production of electricity from fossil fuels
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
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
Geothermal electricity generation
Cold water is heated by the rocks and returned as hot water or steam which can be used to turn turbines to generate electricity
Generating energy reliably on a national or global level requires the use of a range of different energy resources, as listed in the table below:
Table of energy resources
Energy resource | Description |
|---|---|
Fossil fuels | Fossil fuels are combusted to heat water to produce steam that turns turbines to generate electricity |
Nuclear | Nuclear fuels are reacted to heat water to produce steam that turns turbines to generate electricity |
Bio fuels | Crops are grown to produce ethanol or methane, which can be used in place of fossil fuels |
Wind | Wind is used to turn turbines to generate electricity |
Hydroelectric | Water is stored at a height, and when released the moving water is used to turn turbines to generate electricity |
Tidal | Water is stored at a height (by a tidal barrage) at high and low tide, when released the moving water is used to turn turbines to generate electricity |
Wave | The motion of the water due to waves is used to turn turbines to generate electricity |
Geothermal | Hot rocks underground are used to heat water to produce steam that turns turbines to generate electricity |
Solar cells | Solar cells use sunlight to generate electricity |
Solar panels | Solar panels use sunlight to heat water in the panel to produce warm water for households |
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.
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