1.Renewable energy:

Resources that constantly renew themselves or that are regarded as practically inexhaustible.These include solar,wind,geothermal,hydro and wood.Although particular geothermal formations can be depleted,the natural heat in the earth is a virtually inexhaustible reserve of potential energy.Renewable resources also include some experimental or less-developed sources such as tidal power,sea currents and ocean thermal gradients.

• Wind power:
  Energy extracted from wind, traditionally in a windmill, but increasingly by more complicated designes including turbines, usually to produce electricity but also for water pumping. The power available from wind is proportional to the area swept by the rotating place and the cube of the wind velocity, but less than half the available power can be recovered.
• Water power:
  Energy obtained from natural or artificial waterfalls, either directly by turning a water wheel or turbine, or indirectly by generating electricity in a dynamo driven by a turbine.
• Solar energy:
  Generally describes those renewable energy sources which directly or indirectly are powered by the sun. The energy transmitted from the sun in the form of electromagnetic radiation. The most successful examples of energy extraction from the sun are so far solar cells used in satellites and solar collectors used to heat water.
• Geothermal energy:
Generated by the heat of the inner earth.
• Chemical energy:
  The energy liberated in a chemical reaction.
• Biomass:

Biomass refers strictly speaking to the total weight of all the living things in an ecosystem. However, it has come to refer to the amount of plant and crop material that could be produced in an ecosystem for making biofuels and other raw materials used in industry, for example.

2.Non – renewable energy:

Energy provided by burnig fossils.

• Natural gas:
  Naturally occurring mixture of gases, both hydrocarbons and non-hydrocarbons, often associated with deposits of petroleum. For domestic and industrial use it can be stored or transported by pipeline, refrigeration, carriers or in drums, in liquefied or gas form.
• Petroleum:
  A comparatively volatile liquid bitumen composed principally of hydrocarbon, with traces of sulphur, nitrogen or oxygen compounds; can be removed from the earth in a liquid state.
• Black coal:
  A natural black graphitelike material used as a fuel, formed from fossilized plants and consisting of amorphous carbon with various organic and some inorganic compounds.
• Nuclear energy:
  The energy released in nuclear reactions or transitions