Renewable & Non-Renewable Energy (WJEC GCSE Physics: Combined Science)

• Energy resources are large stores of energy that can be used to generate electricity, heat building, and provide fuel for transport
• There are two types of energy resource:
  • Renewable
  • Non-renewable
• Renewable energy resources are defined as

An energy source that is replenished at a faster rate than it is being used 

• This means that renewable energy resources will not run out

• Examples of renewable energy technologies are:
  • Hydroelectric
  • Wind power
  • Wave power
  • Tidal power
  • Solar power
  • Biofuels (including animal waste, wood, and fast growing crops)
  • Geothermal
• There are advantages and disadvantages to each type of energy resource so generally a mixture of technologies are used

Table of Advantages & Disadvantages of Renewable Energy Technologies

Technology	Advantages	Disadvantages
Hydroelectric	Reliable Can produce large amounts of energy  Can be switched on and off quickly & easily (almost instant start up time) Produces no pollution or greenhouse gases No fuel costs	Can involve flooding large areas People and wildlife living in those areas are displaced Habitats are destroyed Building of dams and reservoirs is expensive  High-voltage power lines are needed to transmit the electricity Drought can affect the supply of water
Wind power	Produces no pollution or greenhouse gases Land can still be used for farming No fuel costs	Not reliable (wind doesn't blow all the time) Each turbine can only produce a small amount of electricity so many are needed High-voltage power lines are needed to transmit the electricity Visual pollution (some people think turbines are ugly)
Wave & tidal power	Tidal is very predictable Large amounts of energy can be generated at regular intervals No fuel costs Produces no pollution or greenhouse gases Both wave and tidal technologies can be turned on and off very quickly	Very few suitable locations for tidal barrages Tidal barrages cause flooding of estuaries, destroy habitats & disrupt shipping Wave technology can disrupt shipping & injure wildlife Wave energy is unreliable (waves are not always large enough)
Solar power	Produces no pollution or greenhouse gases Good for use in remote places Readily available Relatively cheap set up costs Can be used in heavily populated areas Can be placed on top of buildings	Unreliable (only works when the sun shines) Each solar cell only produces a small amount of electricity so many are needed Solar farms take up lots of land
Biofuels	Crops are carbon neutral (the CO2 produced when burned is equal to the CO2 absorbed by photosynthesis when growing)	A lot of farm land is required to grow the crops or wood Carbon dioxide is still released into the atmosphere
Geothermal	Reliable Power stations are usually small Produces no pollution Cheap form of energy	Not many suitable places Harmful gases can be released from underground

• Non-renewable energy resources are defined as

An energy source that is not replenished at a faster rate than it is being used 

• This means that non-renewable energy resources are finite and will eventually run out

• Examples of non-renewable energy technologies are:
  • Fossil fuels
    • Coal
    • Oil
    • Natural gas (methane)
  • Nuclear

Fossil Fuels

The three fossil fuels are coal, oil and natural gas

• There are advantages and disadvantages to each type of energy resource so generally a mixture of technologies are used

Table of Advantages & Disadvantages of Non-renewable Energy Technologies

Technology	Advantages	Disadvantages
Fossil fuels	Reliable Can produce large amounts of energy  Relatively cheap	Produce sulphur dioxide (which causes acid rain) Produces carbon dioxide ( a greenhouse gas which contributes to global warming) Coal produces soot which damages buildings and plants and causes breathing difficulties Large amounts of fuel are needed
Nuclear power	Reliable No pollution or greenhouses produced Can produce large amounts of energy	Nuclear power stations are expensive to build Nuclear power stations are expensive to decommission Produces radioactive waste that needs to be stored for thousands of years