Source of Energy || Class 10th Science || CBSE Notes || Study World
·
Source of Energy
§ Renewable Source of Energy.
·
Fuel
·
Ignition or Kindling Temperature
·
Calorific or Heat value
·
Characteristics of a good fuel
·
Conventional source of energy
·
Fossil Fuel
§ Formation of Fossil Fuel
§ Pollution caused by
fossil fuel
§ Controlling pollution
caused by fossil fuel
·
Coal & Use of coal
·
Petroleum
·
LPG Liquefied Petroleum Gas
§ Advantages of LPG
:
§ Danger of LPG
§ Precaution for using LPG
·
Natural Gas
·
Thermal Power Plant
§ Construction
·
Alternate Source of Energy
·
Non conventional source of energy
·
Hydroelectric Energy
§ Principle of
Hydroelectric Power Plant
§ Construction
·
Dam and Reservoir
§ Control Gate
§ Penstock
§ Water turbine
· · Generator
§ Working:
§ Advantages of Generating
Hydroelectricity:
§ Disadvantages of
generating Hydroelectricity:
·
Wind energy
§ Construction and
Working:
·
Solar energy
·
Solar Cooker
§ Construction
§ Working
§ Advantages
§ Limitation
·
Solar Cell
§ Advantages of Solar
Panel:
§ Disadvantages of Solar
Cell
§ Use of Solar Cell
·
Biomass Energy
·
Cow Dung as a Biomass
·
Biogas Plant
§ Construction
§ Working:
§ Use of Biogas/Advantages
of biogas
·
Energy From the Sea
·
Tidal Energy
§ Limitation
·
Ocean Thermal Energy
§ Limitation
·
Sea Wave Energy:
§ Limitation:
·
Geothermal Energy:
·
Nuclear Energy:
§ Nuclear Fission
§ Nuclear Fussion
·
Nuclear Power Plant
§ Working:
§ Advantages of Nuclear
Energy:
§ Disadvantages of Nuclear
Energy
·
Einstein’s Mass Energy Relation:
Non-renewable
Source of Energy:-
Those
sources of energy which have accumulated in nature over a very, very long time
and not cannot be quickly replaced when exhausted are called non-renewable
source of energy.
For
example :- Fossil fuel Coal Petroleum natural gas and nuclear fuel like uranium
fuel etc.
Renewable
Source of energy :- Those source of
energy which are being produced continuously in nature and are inexhaustible are
called renewable source of energy.
For example:- Wind energy, solar energy,
energy from ocean, biomass energy, hydro energy, geothermal energy, etc.
Fuel:
These are the material which for brunt to produce energy in the form of heat
and light. E.g. Coal, charcoal Petrol, diesel, kerosene oil, etc.
Ignition
or Kindling Temperature: It is the minimum temperature at which a substance
catch fire and start burning.
Calorific
or heat value: It is amount of heat produced by burning a unit mass of substance
completely in the presence of air. Its unit is KJ/gm or J/Kg.
Characteristics
of a good fuel: Following
are the characteristics of a good fuel:
(1) It
should have a high calorific value
(2) It should have proper ignition temperature
(3) It should have a moderate rate of combustion.
(4) It should be cheap convenient to use and easy
to handle.
(5) It should not leave any residue.
(6) It should not cause any pollution.
(7) It should burns smoothly.
(8) It should not produce any harmful gas.
(9) It should be easily available.
(10) It should be easy to transport.
Conventional
source of energy:
The
traditional source of energy which is familiar to most people are called
conventional source of energy. E.g. wood, charcoal, coal, solar energy, biomass
energy, fossil fuel, petrol, etc.
Fossil
Fuel: They are described as the pre-historic dead remain of plant and animal
that get worried under the surface of earth million of year ago. E.g. Coal,
Petroleum and natural gas, etc.
Formation
of fossil fuels: Fossil
fuel are supposed to being formed from dead remain of plant and animal, that
got beautifully preserved in nature million of years ago due to earthquake and volcanoes in the
absence of air due to chemical effect of heat, pressure and bacteria. The remains of plant
and animals convert into fossil fuels like Coal, Petroleum, and natural gas.
Fossil
fuel should be used carefully. As they are very important non-renewable source
of energy which got exhausted and cannot be regenerated.So they are very
precious and should be used with great care, so that fossil fuels last as long
as possible.
Coal : Coal is a complex mixture of a compound of carbon, hydrogen and oxygen and some
free carbon. Some small amount of nitrogen and sulphur compounds are also
present in coal.
Use
of coal : Following are the uses of coal:-
(1) Coal
is used as a fuel for heating purpose in home and industries.
(2) Coal
is used as a fuel in thermal power plant to produce electricity.
(3) Coal is used to make coke, and this coke is used as a reducing agent in the
extraction of metals.
(4) Coal
is used in the manufacture of fuel like coal gas.
(5) Coal
is used in manufacture of petroleum and synthetic natural gas.
(6) Coal
is important, because it can be used as a source of energy as such, or
(7) it can
be converted into other form of energy like coal gas, electricity and synthetic
petrol.
Petroleum: Petroleum is a dark coloured viscous and foul smelling crude oil.The name
petroleum means rock oil as “Petra =
rock” “ileum = oil”
It
is called petroleum because it is found under the crust of earth trapped in
rocks.
The
crude oil petroleum is a complex mixture of several solid, liquid and gaseous
hydrocarbon mixed with water, salt and earth particles.
The
fractional distillation of petroleum gives us the following fractions which can
be used as fuel : Petroleum gas,Gasoline,Diesel, Kerosene and fuel oil.
LPG
Liquefied Petroleum Gas: LPG stand for Liquefied
Petroleum Gas and consists mainly of butane alongwith small amount of propane
and ethane which has been liquefied by pressure a strong smelling substance.
A
strong smelling substance called ethyl mercaptan(C2H5S4)
is added to LPG cylinder to help in the detection of LPG.
Advantages of LPG :
(1) LPG has a high calorific value, so it is
good fuel. The calorific value of LPG is about 50 KJ/g. that is when 1 gram of
LPG burn in a gas stop, it produces a 50 kJ of heat energy
(2)
LPG burns with a smokeless flame and so does not cause any air pollution.
(4)
LPG is easy to handle and convention to store.
(5)
LPG is very neat and clean domestic fuel.
Danger
of LPG: Through LPG is an extreme good domestic food but it is can be dangerous
too. LPG is highly inflammable gas that it catch fire easily. Any leakage from
the cylinder will form an explosive mixture in the kitchen and on lightning the
matchstick an explosion will take place and the whole kitchen will be set on
fire and person working in the kitchen may be brunt.
Precaution
for using LPG: Following are the precaution for using LPG:-
(1)
Before lightning a matchstick we should make sure that there is no foul smell
of leaking gas in the kitchen.
(2)
We should not use any hot flame like a kerosene lamp, Kerosene stove or
electric heater near the gas cylinder.
(3)
We should not use a leaking gas cylinder. The gas agency should be informed and
the leaking cylinder should be replaced soon.
(4)
The rubber pipe should be checked periodically for any wear and tear.
(5)
In order to light the gas stove, we should first open the volume of cylinder
and then turn on the knob of gas stove.
(6)
In order to put off the gas stove, we should first close a valve of cylinder
and after that the knob of the gas stove should be turn off.
(7)
When the gas is not being used the valve of the gas cylinder and the gas stove
must be kept of closed.
Natural
Gas: Natural
gas is another important fuel. Natural gas consists mainly of methane (CH4)
with small quantity of ethane propane.
Natural
gas is found under the earth crust either alone or along with above the
petroleum deposits.
(1) Natural
gas is used as a domestic and industry fuel.
(2) Natural
gas is used as a fuel in thermal power plant for generating electricity.
(3) CNG
( Compressed Natural Gas ) is used as a
fuel in transport vehicle like car bus and truck.
Thermal Power Plant : Thermal Power Plant
is also known as thermal power station. Water is made to enter in the system
and then heated, later which turn into the stream. The steam spins in a steam turbine which efforts to
electrical generator
Construction:
Coal is burnt in a furnace to produce heat. This heat boils the water in the boiler
B to form steam. The steam formed from the boiling water builds up a pressure. The
hot steam at high pressure is introduced into the turbine Chamber having a
steam turbine.
The
steam passes over the blade of the turbine as the high pressure Jet making the
turbine rotate. The Shaft S of
turbine is connected to a generator G. When the turbine rotates, its shaft
rotate and drive the generator. The generator produce electricity. The spent
steam coming out of the turbine Chamber is cooled. On cooling, steam condensed
to form water. This water is again send to the boiler to form fresh steam. This
process is repeated again and again.
Pollution
caused by fossil fuel: The main disadvantages of fossil fuel is that the
burning of fossil fuels cause a lot of pollution in the environment this is
explained below:
(1) The burning of fossil fuel produce acidic gases are sulphur
dioxide and nitrogen oxide.
(2) The burning of fossil fuel produce large amount of
carbon dioxide which goes into ear and cause global warming.
(3) The burning of
fossil fuel produced lot of smoke which pollute and cause asthma , cough.
(4) The burning of
coal leave a lot of smoke. It also put tiny particle of ash called fly ash into the air
causing air pollution.
Controlling pollution caused by fossil fuel:
(1) The
pollution of air caused by burning petroleum fuel in vehicle can we control by fitting the vehicle with catalytic converters.
(2) The pollution of air caused
by burning coal in thermal power plant and factories can be controlled by washing down the smoke and acidic gases by water in a scurbber.
(3) The pollution
caused by thermal power plant and factory can also be controlled by electrostatic precipitation in their Chimneys.
Alternate Source of Energy
Non conventional source of energy: These source of energy which are
not based on the burning of fossil fuel or splitting of atom of nuclear fuel
called alternative source of energy or non conventional source of energy. The example of alternate source of energy are: Hydroelectric energy, Solar
energy, Biomass energy, Tidal energy, Sea wave energy, Thermal Energy and
geothermal energy.
Hydroelectric Energy
Principle of Hydroelectric Power Plant: The kinetic energy developed due to gravity in the following butter from
higher level to lower level is utili
sed to rotate it Vine to produce
electricity
Construction:- It consists of following parts.
Dam
and Reservoir: The dam is constructed on large river in hilly areas to ensure sufficient
water storage at height.
Control
Gate: The amount of water which is to be released in the penstock can controlled
by control gate.
Penstock:
A plastic is a huge steel pipe which carries water from reservoir to the
turbine.
Water
turbine: Water from Penstock is taken into the water turbine. The turbine is
mechanically coupled to an electric generator. Kinetic energy of the water
drive the turbine and consequently the generator that driven.
Generator:
When the turbine blade are rotated it derives the generator and electricity is
generated which is then stepped up with the help of transformer for the
transmission.
Working:
Water stored in the reservoir is allowed to fall through penstock to the
turbine. The turbine installed at the bottom of the dam.
Since, the water fall through a
large height from the dam, it flow very fast. The high pressure jet of fast
flowing water push the blade of the turbine with a great force and make the
turbine rotate rapidly, The turbine is connected to the generator which taken
them derive and produce electricity.
Advantages
of Generating Hydroelectricity:
(1)
It does not produced environmental pollution.
(2)
Flowing water is a renewable source of energy which will never exhausted.
(3)
The construction of dam on river help in controlling flood and irrigation
.
Disadvantages
of generating hydroelectricity:
The
Problem associated with the production of electricity by hydroelectric power
station are many. Some of these are given below:
(1)
Large area of agricultural land, a vast variety of flora and fauna (Plant and
animals) as well as human settlement(or Villages ) get submerged in the water of reservoir formed by dam.
(2)
The construction of dam also disturb the ecological balance in the downstream
area of the river.
(3)
The vegetation which is summarised under water at dam site rods under anaerobic
conditions and produce a large amount of methane which is a greenhouse gases
and hence harmful for the environment.
Wind
energy : Moving air is called wind. The energy possessed by wind is due to the
high speed. So the wing process kinetic energy.
The
energy of wind is used for generating electricity through wind power generator.
Construction
and Working:
The windmill used for generating electricity is called wind turbine
and the complete setup of generating electricity by using wind energy is called
wind generator.
A
wind generator is as shown in figure then the fast moving winter strike the blade
of wind turbine than the wind turbine starts rotating continuously. The shaft of
wind turbine is connected to a small generator. When the wind turbines rotate, its
shaft also rotates and drives the generator. The generator produce electricity.
Solar
energy : The
sun is a source of all energy. the energy obtained from the sun is called solar
energy.
A device which get heated by using sun’s heat
energy is called solar heating device. A solar cooker and solar water heater
are solar heating device. all the Solar heating device are design in such a way
that they help in collecting as much Sun’s heat as possible.
Solar
Cooker: It is a device which is used to cook food by utilising the heat energy
radiating by the sun.
Construction:
A solar cooker consists of an insulated metal box or wooden box which is
painted all black from inside. There is a thick glass sheet cover on the glass
and a plane mirror reflector is also attached to the box is as shown in figure.
The food to be to be cooked is put in metal containers which are painted black
from outside.
Working:
In order to cook food, the Solar Cooker
is kept in a sunshine outside the house, the reflector of solar cooker is adjusted
in such a way that it faces the sun, when the sun’s ray falls on the reflected. The reflector send
them to the top of solar cooker box in the form of strong beam of light. Once the
heat entered into the box, the glass cover does not allow them to go back.
The
temperature of cooker box rise to about 100° C to 140° C into two or three hours.
The food material like rice, pulse and vegetable can be cooked in a box type solar cooker.
Advantages:
The
important advantages of solar cooker are:
(1)
The use of solar cooker for cooking food saves precious fuel like coal, Kerosene
and LPG.
(2)
It also does not produce smoke.
(3)
When food is cooked in solar cooker, it it’s nutrient do not get destroyed.
(4)
In a solar cooker four item can be cooked at same time.
Limitation:
Following are the limitation of solar cooker:
(1)
The Solar Cooker cannot be used at night.
(2)
If the day sky is covered with clouds, the Solar Cooker cannot be used for
cooking food.
Solar
Cell: Solar cell used the energy of sunlight to produce electricity. Thus solar
cell is a device which convert Solar energy directly into electricity.
A
solar cell is usually made of from silicon. A simple solar cell consists of
sandwich of a silicon-boron layer and a silicon arsenic layer. The amount of boron
and arsenic present in the two silicon
layer is however very small. A small piece of wire is is soldered at top and also
in bottom. The strength of current produce depend on the brightness of the
sunlight.
A
single solar cell produce only a small amount of electricity. In those cases
where more electric power is needed, a large number of solar cell are joined
together. This group of cell is called solar
cell panel or just solar panel.
Advantages
of Solar Panel:
(1)
The main advantages of Solar cell are that they have no moving parts, their required
almost no maintenance and work quite satisfactory. Without the use of any light
focus device.
(2)
They can also used in hilly area where the laying of usual power transmission
line is difficult and expensive.
Disadvantages of Soler Cell:
The
main disadvantage of solar cell is that, they are very expensive. This is due
to the following reason.
(1)
The spherical Silicon needed for making solar cell is very expensive.
(2)
Silver wire used to interconnect solar cell for making solar cell panel is very
expensive.
(3)
They can convert only about 25% of the light energy falling on them into electricity.
Use of Solar Cell:
(1)
Solar cell are used for producing electricity in artificial satellites and
space probes.
(2)
Solar cell are used are used for providing electricity to remote in assessable
and isolated place.
(3)
Solar cell are used in street light, traffic signal.
(4)
Solar cell are also used in many electronic device like calculator, watches
etc.
Biomass Energy
The
dead remains or dead parts of plant and trees and the waste material of the
animals are called Biomass Energy.
(1) Wood
is also Biomass.
(2) When
wood is burnt, lot of heat is produce. So, wood also give us biomass
energy.
(3)Wood
is renewable source of energy.
But,
the traditional use of wood as a fuel has many disadvantages.
For
example;
(1)
The burning of wood produce a lot of smoke which polluted the air.
(2) Wood has very low caloric value being only
17 KJ/g
Wood can be converted into
a much better fuel called charcoal
Charcoal
can be prepared from wood as follow:
When
wood is burnt in a limited supply of air than a water and other volatile substance
in it get removed, and a black substance Charcoal is left behind. It is better
fuel than wood because it has a high calorific value than wood about 33 KJ/g.
Cow Dung as a Biomass:
It is also known as cattle dumg or animal dung. Cow dung is excreta of cattle such as cow and
buffaloes etc. When Cow dung is brunt it produces heat and this
heat is used for cooking.
Biogas
Plant: Biogas Plant are pit sites where the anaerobic fermentation of biomas is
carried out to produce biogas.
Construction:
Working:
The
dung and water slurry is left in the digestor initially for a period of 50-60
days. The dung undergoes anaerobic fermentation in the presence of water with
gradual evolution of biogas, which collects in the dome and used as a fuel by
using gas valve and delivery pipe.
The
spend slurry come out through overflowed tank which can be used as manure in
the field.
Use
of Biogas/Advantages of biogas:
(1)
It is used as a fuel for cooking food.
(2)
It does not cause any pollution.
(3)
Biogas has a high calorific value.
(4)
There is no short storage problem as it supplied directly to the gas stove.
(5)
Biogas is also used for Lightning.
(6)
Biogas is also used for generating electricity.
Energy From the Sea
The
energy from the sea can be obtained mainly in three forms.
(2)
Wave energy
(3)
Ocean Thermal Energy
(1) Tidal Energy: Tides
are the huge sea waves which kept billions of litre of water in movement as
they built up and recede twice a day. The tidal energy can be utilised by constructing
the tidal dams.
The
sea water rise during high tides is trap by using tidal barrage and allowed to
fall on water turbine to generate electricity.
Limitation:
Following are the limitation of tidal energy:
(1)
The power output is variable.
(2)
The conversion efficiency is very low.
(3)
Very few sites are available for constructing tidal barrage.
Ocean Thermal Energy:
There is always a temperature difference between the water in the surface of
ocean and at the deeper level. At many place the temperature difference may rise
to 20° C which produces energy in the form of Ocean Thermal Energy that can be
converted into electricity.
Limitation:
Followings are the limitation of Ocean Thermal Energy:
(1)
A lot of capital investment is required.
(2)
Conversion efficiency is very low.
Sea Wave Energy: Due
to blowing wind on the surface of ocean/ sea at very fast speed. Sea wave move on
its surface and the kinetic energy of Sea
waves is used to generate electricity.
Limitation:
Followings are the limitation of Sea Wave Energy :
(1)
Present available technology is very expensive.
(2)
The power output is variable.
(3)
Marine animal could be affected.
Geothermal Energy: Geo
means Earth and thermal means heat. Thus geothermal Energy is the heat energy from hot rocks
inside the earth. This heat is used as a source of producing electricity.
Nuclear Energy:
The
energy released during a nuclear reaction is called nuclear energy. It can be
obtained by two types of nuclear reactions.
(1)
Nuclear Fission, and
(2)
Nuclear fusion
(1) Nuclear Fission
: The word fission means to split up into two or more part. The process in
which the heavy nucleus of the radioactive atom such as uranium, plutonium or thorium
split up into smaller nuclei when bombarded with low energy neutron is called
Nuclear Fission.
The
fission reaction can be represented in the form of equation as:
The
energy produced during nuclear fusion reaction is used for generating
electricity has nuclear power plant.
Nuclear
Power Plant
A
power plant in which the heat is required
to make a steam and turn turbine to generate electricity and is obtained by nuclear
reaction is called a nuclear power.
In
nuclear power plant, the fision of the nuclear fuel uranium -235 is carried out
in a steel pressure vessel V of Reactor
R. The enriched uranium-235 rod marked
A are inserted in the core, made of graphite block inside the reactor. Graphite
is a moderator.
Baron
rods are called as control rod because they absorb the excess neutrons when the
reaction is out of control.
The
reactor is enclosed in a concrete chamber M having thick walls to absorbs
neutrons. Liquid Sodium or carbon dioxide is used as a coolant to transfer the
heat produced in a reactor. Rest of the
arrangement at a nuclear power plant is shown in the figure:
Working:
The control fission of Uranium-235 in the nuclear reactor produces a lot of
heat energy. Liquid sodium absorbed the heat produced in the reactor. This
extremely hot sodium is then passed into the coil of the heat exchanger. team
at sodium is then passed into the coil of the heat exchanger containing water.
Water absorb heat from hot solution and boil to form steam. The steam at high
pressure is introduced into a turbine chamber Si having a turbine. The pressure
of the steam rotate the turbine which then derive the generator and generator
produce electricity.
Einstein’s Mass Energy Relation:
-
Einstein
said that mass and energy are equivalent and are related by the equation.
E
= mC2
Here
E is amount of energy produce, m is the mass destroyed and C is the speed of
light in vacuum.
For
example: If a mass of 1 kg of any matter
could be destroyed in a nuclear reactor, then the amount of energy produced in
by Einstein’s Mass-energy relation.
E
= mC2
E
= 1 × (3 × 108)2
E
= 9 × 1016 J
Thus
1 kg of mass produces 9 × 1016 Joule of energy.
Energy
Units for Expressing Nuclear Energy.
1
electron Volt = a Charge magnitude ×
Potential of 1 Volt
i.e.
1 ev = 1.6 × 10-19 c × 1 Volt
= 1.6 × 10-19 J
The
electron volt is very big small bigger unit called million electron volts
1
million electron volts = 1• 602 × 10-19 × 106 Joules
Or
1 mev = 1• 6 × 10-13 Joules
Nuclear Fussion:-
The word fussion means to join or to combine. The process in which two nuclei
of light elements like hydrogen combine to form a heavy nucleus like that of
helium is called nuclear fussion. The fussion reaction can be written as
A
fussion process is just opposite to fission process.
Advantages of Nuclear Energy:
(1)
It produces a large amount of energy from a very small amount of Nuclear fuel.
(2)
Once the nuclear fuel (like Uranium - 235) loaded in the reactor. The nuclear
power plant can go on producing electricity for 2-3 year at a stretch.
(3)
It does not produce gases like CO2 which contributes to green house
effects.
Disadvantages
of Nuclear Energy:-
(1)
The waste material of nuclear radioactive which kept on emitting harmful
nuclear radiation for thousand of years.
(2)
There is a high risk of accident in nuclear reactors.
(3)
The high cost of installation is also a disadvantage.
(4)
The Limited stock of Uranium is also a major disadvantage.
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