Energy comes in different forms and one form can be converted to another.
For example if we drop a plate from a height, the potential energy of the plate
is converted mostly to sound energy when it hits the ground.
If we light a candle, the process is highly exothermic so that the chemical
energy of the wax is converted into heat energy and light energy on burning.
A Good Source of Energy would be one
which has high calorific value
be easily accessible
be easy to store and transport
be economical
Dams are constructed to :
Prevent flooding of river, provide water for irrigation & to generate
hydroelectricity.
Disadvantages of construction of Big Dams
1. Submerging/Loss of large variety of Flora fauna and human settlements &
roting of submerged vegetation release green house gas (CH4).
2. They pose dangers of earthquakes, landslides etc.
Biomass is Agricultural & animal wastes that can be used as a fuel. Eg. of
Biomass – Firewood, cattle dung, sewage, dry leaves, stems & bagasse.
Normally biomass has low calorific value & produce lot of smoke when they
are burnt. Their efficiency as a good fuel has been increased tremendously
with the application of technology. For Eg. cowdung becomes efficient &
cheap good fuel in a Bio-gas plant.
Charcoal is better fuel than wood because it do not contain water & other
volatile material which are present in wood.
Charcoal burns without smoke, flames & has high calorific value.
Bio-gas is an excellent fuel & contain 75% of Methane (CH ). It burns 4
without smoke, leaves no reciters like ash, with high heat capacity.
Biogas is produced by anerobic decomposition of the slurry (cowdung +
water mixture) by microbes. This process is applied in a Bio gas plant.
The Biogas is stored in the gas tank from which they are drawn through pipes
for use in a Bio-gas plant
Bio gas is used for lighting, cooking in the rural areas. While the slurry left
behind is used as excellent manure, rich in nitrogen and phosphorous
The large scale use of Bio-wastes & sewage material provide a safe and
efficient method of waste-disposal besides supplying energy and manure.
WIND ENERGY
Unequal heating of the landmass and water bodies by solar radiation
generates air movement & causes winds to blow. This kinetic energy of the
wind can be used to do work.
This energy is utilised to lift water from the well & to generate electricity in
the wind mill.
Actually the rotatory motion of the windmill is used to turn the rotor of the turbine
which then generate electricity through Dynamo.
The output of a single windmill is quite small so a number of windmills are erected
over a large area - called wind energy farm.
India Ranked Fifth in the world in harnessing wind energy for the production of
electricity. It is estimated that nearly 45,000 MW of electric power can be
generated if India’s wind potential is fully exploited.
The minimum wind speed for wind mill to serve as a source of energy is
20KMPH.
Advantages of Wind Energy
1. Eco friendly
2. Efficient source of renewable energy.
3. No recurring expenses for production of electricity
Limitations of Wind Energy
1. Wind energy farms need large area of land
2. Difficulty in getting regular wind speed of 15-20 KmPH.
3. Initial cost of establishing wind energy farm is very high.
4. High level of maintenance of blades of wind mill.
Non Conventional Sources of Energy
Solar Energy :
The energy emitted by the sun in form of heat and light is called solar energy.
Solar Constant = 1.4kJ/s m2
Outer edge of the earth receives solar energy equal to 1.4 kJ/sm2 which is known as
solar constant.
Solar energy devices :
A large number of devices that utilize solar energy directly like :
(i) Solar Cooker
(ii) Solar furnaces
(iii) Solar cells
(iv) Solar water heaters
Solar heating devices :
Use black painted surface because black surface absorbs more heat as
compared to white or other surface.
Use of glass plate because it allows shorter infrared radiations to pass through
it but doesn’t allow the longer wavelength infrared radiations to through it,
that results in increase in temperature.
Solar Cooker :
Box type solar CookerIt consists of a rectangular box which is made up of material such as plastic or
wood.
Box is covered with black sheet and its inner walls are painted black to
increase heat absorption.
Solar cookers are covered with glass plate and have mirrors to focus the rays of
the sun and achieve a higher temperature.
Advantages :
1. Use energy which is available in plenty (Solar Energy)
2. Is pollution free.
3. More than one food can be cooked simultaneously
Disadvantages :
1. Cannot be used for frying or baking purpose.
2. Food cannot be cooked at night or on a cloudy day.
3. Direction of reflector of solar heating has to be changed from time to time to
keep it facing the sun
Solar Cells :
?Solar cells are device that convert Solar energy into electricity.
?Develops a voltage of 0.5 – IV and can produce about 0.7W of electricity.
Advantages of Solar Cell
1. Require a little maintenance
2. Have no moving part.
3. No focussing device is required
4. Can be set up in remote areas.
5. Environment - friendly i.e. do not cause pollution.
Disadvantage of Solar Cells
1. It require high cost
2. Efficiency is low
3. Initial cost of installation is quite high.
Uses of Solar Cell
1. Used in calculators, watches etc.
2. Used in artificial satellites and space probes.
3. It is used in radio or wireless transmission system.
Solar Panel
A large number of Solar Cells connected to each other in an arrangement is called
solar panel.
Material used for making solar cells
Silicon
Silver is used for inter connection of cells.
Energy from the Sea or Ocean
The energy from the sea is available in the following forms.
(i) Energy of sea waves
(ii)Tidal energy
(iii) Ocean Thermal Energy.
(i) Energy of Sea Waves
The waves are generated by the strong winds that blows across the sea.
The kinetic energy of this moving water rotates the turbine of a generator
Limitation
When strong winds stop blowing, the generator stops producing electricity
(iii) Tidal Energy
The tidal energy possessed by water during tides.
The tides are caused due to gravitational force of attraction exerted by the
moon on the water of the ocean.
This form of energy is harnessed by constructing a dam across a narrow
opening to the sea.
A turbine fixed at the opening of the dam converts tidal energy to electricity.
(iii) Ocean Thermal Energy
The power plants used to harness the ocean thermal energy is known as “Ocean
Thermal Energy Conversion plant) (OTEC)
Temperature difference between surface water and water at the depth of 2km
should be 20°C or more.
The warm surface water is used to boil ammonia (liquid)
The vapours of the liquid are used to run the turbine of generator.
The cold water (from deeper layers) is pumped up to condense the vapour into
liquid.
Geothermal Energy
1. Energy stored as heat inside the earth
2. The steam of underground water is taken out by sinking pipes through holes
drilled in the earth’s crust. The steam under high pressure is used to rotate the
turbines of the generator to produce electricity.
Nuclear Energy
Nuclear energy is the energy which is stored in the nucleus of an atom.
Nuclear energy is of two types
(i) Nuclear fission ® nucleus of a heavy atom (Uranium) when bombarded with
low energy neutron split (break down) into lighter nuclei and huge amount of
energy is released
(ii) Nuclear Fusion® When two lighter nucleic join up to form heavy nucleus
and tremendous amount of energy is released.
Nuclear fission process is utilized in nuclear reactors to produce electricity.
Major Nuclear power plants : Tarapur, Rana Pratap Sagar, Kalpakkam
Advantages of Nuclear Energy :
1. Large amount of energy is released.
2. In nuclear power plant, the nuclear fuel is inserted once to get energy over a
long period of time.
Disadvantages of Nuclear Energy :
1. High cost of installation.
2. Environmental contamination may occur due to imporper nuclear waste
disposal.
Environmental Consequences
1. Energy sources should be used judiciously otherwise it would disturb the
environment.
2. Use of clean fuels like CNG (compressed natural gas) because burning of
fossil fuel causes green house effect.
3. Assembly of devices like solar cell (otherwise renewable source of energy)
would have caused environmental damage.
How long will energy source last
the sources of energy can be divided into two catagories :
(i) Renewable sources of energy eg wind, sun, biogas
(ii) Non renewable sources of energy eg. Coal, Petroleum, Natural Gas.
Continuous use of non renewable source of energy is a matter of concern because.
ultimately the deposit of these sources will be completely finished on the other
hand renewable sources of energy will last forever eg sun as a source of energy will
be available for a very long period of time
For example if we drop a plate from a height, the potential energy of the plate
is converted mostly to sound energy when it hits the ground.
If we light a candle, the process is highly exothermic so that the chemical
energy of the wax is converted into heat energy and light energy on burning.
A Good Source of Energy would be one
which has high calorific value
be easily accessible
be easy to store and transport
be economical
Dams are constructed to :
Prevent flooding of river, provide water for irrigation & to generate
hydroelectricity.
Disadvantages of construction of Big Dams
1. Submerging/Loss of large variety of Flora fauna and human settlements &
roting of submerged vegetation release green house gas (CH4).
2. They pose dangers of earthquakes, landslides etc.
Biomass is Agricultural & animal wastes that can be used as a fuel. Eg. of
Biomass – Firewood, cattle dung, sewage, dry leaves, stems & bagasse.
Normally biomass has low calorific value & produce lot of smoke when they
are burnt. Their efficiency as a good fuel has been increased tremendously
with the application of technology. For Eg. cowdung becomes efficient &
cheap good fuel in a Bio-gas plant.
Charcoal is better fuel than wood because it do not contain water & other
volatile material which are present in wood.
Charcoal burns without smoke, flames & has high calorific value.
Bio-gas is an excellent fuel & contain 75% of Methane (CH ). It burns 4
without smoke, leaves no reciters like ash, with high heat capacity.
Biogas is produced by anerobic decomposition of the slurry (cowdung +
water mixture) by microbes. This process is applied in a Bio gas plant.
The Biogas is stored in the gas tank from which they are drawn through pipes
for use in a Bio-gas plant
Bio gas is used for lighting, cooking in the rural areas. While the slurry left
behind is used as excellent manure, rich in nitrogen and phosphorous
The large scale use of Bio-wastes & sewage material provide a safe and
efficient method of waste-disposal besides supplying energy and manure.
WIND ENERGY
Unequal heating of the landmass and water bodies by solar radiation
generates air movement & causes winds to blow. This kinetic energy of the
wind can be used to do work.
This energy is utilised to lift water from the well & to generate electricity in
the wind mill.
Actually the rotatory motion of the windmill is used to turn the rotor of the turbine
which then generate electricity through Dynamo.
The output of a single windmill is quite small so a number of windmills are erected
over a large area - called wind energy farm.
India Ranked Fifth in the world in harnessing wind energy for the production of
electricity. It is estimated that nearly 45,000 MW of electric power can be
generated if India’s wind potential is fully exploited.
The minimum wind speed for wind mill to serve as a source of energy is
20KMPH.
Advantages of Wind Energy
1. Eco friendly
2. Efficient source of renewable energy.
3. No recurring expenses for production of electricity
Limitations of Wind Energy
1. Wind energy farms need large area of land
2. Difficulty in getting regular wind speed of 15-20 KmPH.
3. Initial cost of establishing wind energy farm is very high.
4. High level of maintenance of blades of wind mill.
Non Conventional Sources of Energy
Solar Energy :
The energy emitted by the sun in form of heat and light is called solar energy.
Solar Constant = 1.4kJ/s m2
Outer edge of the earth receives solar energy equal to 1.4 kJ/sm2 which is known as
solar constant.
Solar energy devices :
A large number of devices that utilize solar energy directly like :
(i) Solar Cooker
(ii) Solar furnaces
(iii) Solar cells
(iv) Solar water heaters
Solar heating devices :
Use black painted surface because black surface absorbs more heat as
compared to white or other surface.
Use of glass plate because it allows shorter infrared radiations to pass through
it but doesn’t allow the longer wavelength infrared radiations to through it,
that results in increase in temperature.
Solar Cooker :
Box type solar CookerIt consists of a rectangular box which is made up of material such as plastic or
wood.
Box is covered with black sheet and its inner walls are painted black to
increase heat absorption.
Solar cookers are covered with glass plate and have mirrors to focus the rays of
the sun and achieve a higher temperature.
Advantages :
1. Use energy which is available in plenty (Solar Energy)
2. Is pollution free.
3. More than one food can be cooked simultaneously
Disadvantages :
1. Cannot be used for frying or baking purpose.
2. Food cannot be cooked at night or on a cloudy day.
3. Direction of reflector of solar heating has to be changed from time to time to
keep it facing the sun
Solar Cells :
?Solar cells are device that convert Solar energy into electricity.
?Develops a voltage of 0.5 – IV and can produce about 0.7W of electricity.
Advantages of Solar Cell
1. Require a little maintenance
2. Have no moving part.
3. No focussing device is required
4. Can be set up in remote areas.
5. Environment - friendly i.e. do not cause pollution.
Disadvantage of Solar Cells
1. It require high cost
2. Efficiency is low
3. Initial cost of installation is quite high.
Uses of Solar Cell
1. Used in calculators, watches etc.
2. Used in artificial satellites and space probes.
3. It is used in radio or wireless transmission system.
Solar Panel
A large number of Solar Cells connected to each other in an arrangement is called
solar panel.
Material used for making solar cells
Silicon
Silver is used for inter connection of cells.
Energy from the Sea or Ocean
The energy from the sea is available in the following forms.
(i) Energy of sea waves
(ii)Tidal energy
(iii) Ocean Thermal Energy.
(i) Energy of Sea Waves
The waves are generated by the strong winds that blows across the sea.
The kinetic energy of this moving water rotates the turbine of a generator
Limitation
When strong winds stop blowing, the generator stops producing electricity
(iii) Tidal Energy
The tidal energy possessed by water during tides.
The tides are caused due to gravitational force of attraction exerted by the
moon on the water of the ocean.
This form of energy is harnessed by constructing a dam across a narrow
opening to the sea.
A turbine fixed at the opening of the dam converts tidal energy to electricity.
(iii) Ocean Thermal Energy
The power plants used to harness the ocean thermal energy is known as “Ocean
Thermal Energy Conversion plant) (OTEC)
Temperature difference between surface water and water at the depth of 2km
should be 20°C or more.
The warm surface water is used to boil ammonia (liquid)
The vapours of the liquid are used to run the turbine of generator.
The cold water (from deeper layers) is pumped up to condense the vapour into
liquid.
Geothermal Energy
1. Energy stored as heat inside the earth
2. The steam of underground water is taken out by sinking pipes through holes
drilled in the earth’s crust. The steam under high pressure is used to rotate the
turbines of the generator to produce electricity.
Nuclear Energy
Nuclear energy is the energy which is stored in the nucleus of an atom.
Nuclear energy is of two types
(i) Nuclear fission ® nucleus of a heavy atom (Uranium) when bombarded with
low energy neutron split (break down) into lighter nuclei and huge amount of
energy is released
(ii) Nuclear Fusion® When two lighter nucleic join up to form heavy nucleus
and tremendous amount of energy is released.
Nuclear fission process is utilized in nuclear reactors to produce electricity.
Major Nuclear power plants : Tarapur, Rana Pratap Sagar, Kalpakkam
Advantages of Nuclear Energy :
1. Large amount of energy is released.
2. In nuclear power plant, the nuclear fuel is inserted once to get energy over a
long period of time.
Disadvantages of Nuclear Energy :
1. High cost of installation.
2. Environmental contamination may occur due to imporper nuclear waste
disposal.
Environmental Consequences
1. Energy sources should be used judiciously otherwise it would disturb the
environment.
2. Use of clean fuels like CNG (compressed natural gas) because burning of
fossil fuel causes green house effect.
3. Assembly of devices like solar cell (otherwise renewable source of energy)
would have caused environmental damage.
How long will energy source last
the sources of energy can be divided into two catagories :
(i) Renewable sources of energy eg wind, sun, biogas
(ii) Non renewable sources of energy eg. Coal, Petroleum, Natural Gas.
Continuous use of non renewable source of energy is a matter of concern because.
ultimately the deposit of these sources will be completely finished on the other
hand renewable sources of energy will last forever eg sun as a source of energy will
be available for a very long period of time
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