• Renewable Energy Sources

    Renewable energy resources: Any energy resources that is naturally regenerated over a short time scale and derived directly from the sun (such as thermal, photochemical, and photoelectric), indirectly from the sun (such as wind, hydropower, and photosynthetic energy stored in biomass), or from other natural movements and mechanisms of the environment (such as geothermal and tidal energy) are called renewable energy sources. Renewable energy does not include energy resources derived from fossil fuels, waste products from fossil sources, or waste products from inorganic sources.

    War, politics and overall demand often dictate the price for fossil fuels, which can fluctuate and cause serious economic problems or supply shortages for some countries. By using renewable energy sources a country can help to reduce its dependency on global markets and thus increase its energy security.


    Advantages and disadvantages of renewable energy sources

    Type of energy

    Where it is from




    Energy from sunlight is captured in solar panels and converted into electricity.

    Potentially infinite energy supply.

    Single dwellings can have own electricity supply.

    Manufacture and implementation of solar panels can be costly.


    Wind turbines (modern windmills) turn wind energy into electricity.

    Can be found singularly, but usually many together in wind farms.

    Potentially infinite energy supply.

    Manufacture and implementation of wind farms can be costly.

    Some local people object to on-shore wind farms, arguing that it spoils the countryside.


    The movement of tides drives turbines.

    A tidal barrage (a kind of dam) is built across estuaries, forcing water through gaps.

    In future underwater turbines may be possible out at sea and without dams.

    Ideal for an island such as the UK.

    Potential to generate a lot of energy.

    Tidal barrage can double as a bridge, and help prevent flooding.

    Construction of barrage is very costly.

    Only a few estuaries are suitable.

    Opposed by some environmental groups as having a negative impact on wildlife.

    May reduce tidal flow and impede flow of sewage out to sea.


    The movement of seawater in and out of a cavity on the shore compresses trapped air, driving a turbine.

    Ideal for an island country.

    More likely to be small local operations, rather than done on a national scale.

    Construction can be costly.

    May be opposed by local or environmental groups.


    In volcanic regions it is possible to use the natural heat of the earth.

    Cold water is pumped underground and comes out as steam.

    Steam can be used for heating or to power turbines creating electricity.

    Potentially infinite energy supply.

    Used successfully in some countries, such as New Zealand and Iceland.

    Can be expensive to set up and only works in areas of volcanic activity.

    Geothermal and volcanic activity might calm down, leaving power stations redundant.

    Dangerous elements found underground must be disposed of carefully.

    Hydroelectric Power (HEP)

    Energy harnessed from the movement of water through rivers, lakes and dams.

    Creates water reserves as well as energy supplies.

    Costly to build.

    Can cause the flooding of surrounding communities and landscapes.

    Dams have major ecological impacts on local hydrology.


    Comparision between Renewable and Non-renewable energy resources


    Renewable energy resources

    Non-renewable energy resources


    It can be used again and again throughout its life.

    It cannot be used again and again but one day it will be exhausted.


    These are the energy resources which cannot be exhausted.

    They are the energy resources which can be exhausted one day.


     It has low carbon emission and hence environment friendly.

    It has high carbon emission and hence not environment friendly.


    It is present in unlimited quantity.

    It is present in limited quantity and vanishes one day


    Cost is low.

    Cost is high.


    Renewable energy resources are pollution free.

    The non-renewable energy resources are not pollution free.


    Life of resources is infinite.

    Life of resources is finite and vanishes one day.


    It has high maintenance cost.

    It has low maintenance cost as compared with the renewable energy resources.


    Large land area is required for the installation of its power plant.

    Less land area is required for its power plant installation.


    Solar energy, wind energy, tidal energy etc are the examples of renewable resources.

    Coal, petroleum, natural gases are the examples of non-renewable resources