Energy Resources (Edexcel IGCSE Physics)

• 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