Part -3 | Non-Conventional sources of energy | English

CHAPTER

SOURCES OF ENERGY 

Part -1 》》 INTRODUCTION TO SOURCES OF ENERGY 

Part -2 》》 CONVENTIONAL SOURCES OF ENERGY 

PART -3

NON-CONVENTIONAL SOURCES OF ENERGY 

Wind Energy: 
• Moving air is called air.
• As we know that any moving object posses kinetic energy.

• This kinetic energy is used to do mechanical work like
1. Generating electricity
2. Propelling sail boats in river and seas.
3. In water lifting pumps.

Wind mill :- 
• wind mill is shown in figure below.
• In wind mill when blowing wind strikes with the bleds of wind mills then it exerts a force on wind mill. Due to this force bleds starts rotating.

• This rotational motion of wind mill can to drive various machines just like water pump, turbine, electric generators, etc.

Advantages of wind mill :- 
• Eco-friendly and efficient source of energy.
• No any expanses for the production of electricity.

Limitations of Wind Energy: 
•Wind farms can only be established at those places where the wind speed is high enough and is more than 15 km/hr for most parts of the year.
• Wind farms need to be established on large tracts of land.
• The sun is the main source of energy for all living beings on this earth.
• Even the energy in the fossil fuels has come from the sun.
• The sun has an endless reservoir of energy which would be available as long as the solar system is in existence.
• Technologies for harnessing the solar energy have been developed in recent times.
• The fan of the windmill has many moving parts; so cost of maintenance and repair is quite high. The fact, that it has to suffer the vagaries of the nature further compounds the problem. Initial cost of establishing a wind farm is very high.

Solar Energy: 

Advantages of solar energy:- 
• It does not cause pollution.
• It is available free of cost.
• It can be put in practical application.
• It is available in abundance in a hot country like ours.

Disadvantage of solar energy:- 
•It is not available in night.
• It is not available in cloudy days.
• It is not available uniformly all the time and at all the places.

SOLAR ENERGY DEVICES:- 
Solar Cooker:
• Solar cooker is very simple in design and mode of function.

• It is usually made from mirrors.
• Plain mirrors are placed inside a rectangular box.
• The light reflected from the plain mirrors concentrates the solar energy inside the solar cooker which generates enough heat to cook food.

Solar Furnace:
• Solar furnace is made like a concave mirror.

• Large solar furnace has many smaller mirrors to compose a very large convex mirror. The thing to be heated is place near the focus of the mirror.

Solar Cells:
• Solar cells are made from silicon.
• The solar panel converts solar energy into electrical energy which is stored in a battery for later use.

Energy from Sea
Tidal Energy: 
• Due to the gravitational pull of the moon, tides happen near seashores.
• Water rushes up near the seashore during a high tide and goes down during a low tide.

• Dams are built near seashores to collect the water which comes during a high tide.
• When the water runs back to the ocean, the flow of water can be utilized to generate electricity.

Wave Energy: 
• Waves can also be a good source of energy.
• Many devices are being designed and tested to produce wave energy.
• For example; a hollow tower is built near the seashore.
• When water gushes in the tube because of wave, it forces the air upwards.
• The kinetic energy of air in the tube is used to run a turbine.
• When the wave goes down; air from up goes down the tube which is also used in running the turbine.

Ocean Thermal Energy: 
• The water at sea surface is hot during daytime, while the water at lower level is cold.
• The temperature differential in water levels can be utilized to generate energy.
• If the temperature differential is more than 20°C, then ocean thermal energy can be utilized from that place.
• For this, a volatile liquid; like ammonia is boiled using the heat from the hot water at the surface.
• The steam of the volatile liquid is utilized to run the turbine to generate electricity.
• Colder water from the surface below is utilized to condense ammonia vapour which is then channelized to the surface to repeat the cycle.

• Various methods of harnessing energy from the sea are still at experimental stages.

Geothermal Energy: 
• The molten rocks from the inside of the earth are pushed in certain regions of the earth.
• Such regions are called the hot spots of the earth.
• When groundwater comes in contact with such hot spots, lot of steam is generated.
• This steam can be harnessed to produce energy.

• Many power plants in New Zealand and USA operate on geothermal energy.