2. Energy
●Energy broadly means the capacity of something, a
person, an animal or a physical system to do work
and produce change.
●Used in science to describe how much potential a
physical system has to change.
Sources of Energy.
Conventional sources of
energy
Non conventional sources
of energy
3. Non Conventional Energy
sources:
1.) Those energy sources which are renewable and
ecologically safe.
2.) Such as solar energy, wind energy, biomass
energy, ocean energy (tidal energy, wave energy,
ocean thermal energy), geothermal energy, nuclear
energy etc.
3.) Some sources of energy are non renewable like
coal, petroleum and natural gas.
4. 4.) About 16% of global final energy consumption
comes from renewable, with 10% coming from
traditional biomass, which is mainly used for heating,
and 3.4% from hydroelectricity.
5.) New renewable (small hydro, modern biomass,
wind, solar, geothermal, and biofuels) accounted for
another 3% and are growing very rapidly.
6.) The share of renewable in electricity generation
is around 19%, with 16% of global electricity coming
from hydroelectricity and 3% from new renewable.
5. Wind energy
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Airflows can be used to run wind turbines.
Wind energy is used in wind mills which converts the
kinetic energy of the wind into mechanical or electrical
energy.
The kinetic energy of wind can be used to do
mechanical work like lifting water from wells or
grinding grains in flour mills.
A single wind mill produces only a small amount of
electricity.
large number of wind mills in a large area are coupled
together to produce more electricity in wind energy
farms.
The minimum wind speed required is15km/hr.
At present Wind power potential of India is 1020 MW
6. Advantages :-
● It is a renewable source of energy.
● It does not cause pollution.
●The recurring cost is less.
●Once the wind turbine is built the energy it
produces does not cause green house gases
Disadvantages :-
● Wind is not available at all times.
● It requires a large area of land.
●A minimum wind speed of 15 km/h is
required.
7. Solar energy :-
• Energy obtained from the sun in
the form of heat and light.
• Energy derived in the form
of solar radiation.
• The solar energy received by the
near earth space is
approximately 1.4
kilojoules/second known as solar
constant
• The heat energy is used in solar
heating devices like solar
cooker, solar water heater, solar
furnaces etc. The light energy is
used in solar cells.
8. Various technologies in
which solar energy can be
used:-
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Solar cookers
Solar hot water systems
Solar dryers
Solar air heaters
Solar desalination systems
Solar batteries
9. Solar cell
• Device which converts solar
energy into electrical energy.
• Solar cells are made from semi
conductors like silicon,
germanium, gallium etc.
• A single solar cell produces a
voltage of about 0.5 to 1 V and
produces about 0.7 W electricity.
• several solar cells are arranged in a
solar panel to produce more
electricity.
10. Advantages of Solar Energy
●After initial investment, all the electricity you
produce is free.
●It is abundant.
●It is everlasting.
●It is available almost everywhere.
●It is free from political barriers.
●Incentives and rebates from governments and
utility companies offset the initial investment.
●Reduce or completely eliminate your electric bill.
●Cost of solar panels are decreasing while
efficiency is increasing.
11. Hydro power plants :-
●In hydro power plants water from rivers
are stored by constructing dams.
●Micro hydro systems are hydroelectric
power installations that typically produce
up to 100 kW of power.
●They are often used in water rich areas as
a remote-area power supply.
●Run-of-the-river hydroelectricity systems
derive kinetic energy from rivers and
oceans without using a dam.
12. Advantages of Hydro power energy:-
● Flowing water is a renewable source of energy.
● The electricity produced does not cause pollution.
●The water stored in dams can also be used to control floods and for
irrigation.
●Once a dam is constructed, electricity can be produced at a constant-
rate.
●Often large dams become tourist attractions in their own right.
Disadvantages :-
● The initial cost is high.
● Large areas of land gets submerged and the decomposition of
vegetation produces methane gas which is a green house gas.
● It causes displacement of people from large areas of land.
13. Biogas plant
• Mixture of gases containing methane, carbon dioxide, hydrogen
and hydrogen sulphide.
• It is produced by anaerobic degradation of animal waste.
• Anaerobic degradation means break down of organic matter by
bacteria in the absence of oxygen.
• The biogas plant has a large underground tank made of bricks and
cement.
• The lower part is the digester and the upper part has a dome with a
gas outlet.
14. • Animal dung is mixed with water in the mixing tank and the slurry
is sent into the digester.
• The gas is taken out through the gas outlet and used for heating and
lighting purposes.
• The slurry left behind is rich in nitrogen and phosphorus and is used
as manure for crops.
• From cattle dung alone we can produce biogas of a magnitude of
22,500 MW annually.
• A sixty cubic feet gobar gas plant can serve the needs of one
average family.
• This gas contains 55 – 70 percent methane, which is inflammable
and it is generally used as cooking gas and for generation of
electricity.
16. Advantages of Biogas
❖ Clean, non-polluting and cheap
❖ Direct supply of gas from tank.
❖ No maintence cost
❖ Does not cause any health
hazard.
❖ provides us both the fuel and
the manure.
