A renewable energy resource is one that is being (or can be) replenished as it is used.

A reliable resource is one which can always be used. Fossil Fuels are reliable. The Sun is unreliable.

The uses of energy resources include: transport, electricity generation and heating.

The main energy resources available for use on Earth include:

  • Fossil fuels take millions of years to form from the fossilised remains of trees and plants
  • Non-renewable
  • Used for transport, electricity generation and heating
  • Reliable
  • Burning fossil fuels releases greenhouse gases which contribute to global warming. Burning coal releases nitrogen oxides which dissolve in water to form acid rain.
  • Uses metals like Uranium and Plutonium which can be made to undergo the nuclear fission process
  • Non-renewable
  • Used for transport (there are some submarines which use nuclear power) and electricity generation
  • Reliable; the power stations can not be turned on quickly so they stay active once they are switched on.
  • The radioactive waste must be stored safely to avoid contaminating the environment, people or wildlife.
  • Bioethanol is an alcohol made from crops. Biofuel can also be plant or farm waste which is burned.
  • Renewable
  • Used for transport, and heating
  • Reliable
  • Burning biofuel releases greenhouse gases which contribute to global warming. Land that is being used to grow the crops used to produce biofuel reduces the land available to grow food.
  • Kinetic energy of the wind is used to turn a turbine which turns a generator to produce electricity
  • Renewable
  • Used for transport (sail boats), and electricity generation
  • Non-reliable (the wind may not be blowing)
  • Releases greenhouse gases. Wind turbines are noisy and some believe unsightly.
  • Water is collected high up behind a dam. When the waters released the kinetic energy of the falling water is used to generate electricity.
  • Renewable
  • Used for electricity generation
  • Reliable; also is used when demand peaks suddenly as the electricity generation starts very quickly
  • The dam and flooding behind it destroys habitats
  • When hot rocks are near the surface of the Earth, the heat can be used to turn water to steam which is used to generate electricity
  • Renewable
  • Used for electricity generation
  • Reliable if there are hot rocks near the surface
  • When the tide flows in and out twice a day, the kinetic energy of the water is used to generate electricity
  • Renewable
  • Used for electricity generation
  • Not reliable as the tide only happens twice a day
  • The equipment used can prevent migration of water life and stop boats from moving freely
  • The kinetic energy of the waves is used to generate electricity
  • Renewable
  • Used for electricity generation
  • Reliable
  • The ocean is a difficult environment for equipment to be positioned in. The equipment can cause problems for boats.
  • The sun can be used to generate electricity using PV (photovoltaic) cells or be used to heat water.
  • Renewable
  • Used for electricity generation, and heating
  • Not reliable; the sun does not always shine and the hours of daylight vary across the seasons.
  • The land taken up for PV cells would otherwise have been used to grow crops.
  • Environmental Advantages
    • renewable / sustainable (energy source)
    • conserves fossil fuels
    • no release of pollutant gases e.g. sulfur dioxide
    • no release of greenhouse gases allow does not release carbon dioxide
    • does not contribute to global warming
  • Environmental Disadvantages
    • noise pollution
    • visual pollution
    • bird kill
    • not always windy so more use of fossil fuel power stations
  • Advantage
    • produce no / little greenhouse gases / carbon dioxide    
    • high(er) energy density in fuel
    • long(er) operating life
  • Disadvantage
    • produce (long term) radioactive waste
    • accidents at nuclear power stations may have far reaching or long term consequences  
    • high(er) decommissioning costs       
    • long(er) start up time
  • produces carbon dioxide / nitrogen oxides
  • that (may) contribute to global warming

Electricity Demand

There are times across a day that we use more electricity; the demand for electricity varies.

We might used more electricity:

  • When we get home from school and put the TV/toaster/kettle on
  • In the morning when we have just woken up and need to use lights & heating
  • In the winter when it gets dark earlier
Graph showing how demand for energy resources changes over 24 hours
Variation between demand in summer and winter over 24 hours
Graph showing how demand for energy resources changes during a football match
On 29 June 2021 there was a big England v Germany football match. The white line shows the variation in electricity demand during the match.