3. NON – RENEWABLE ENERGY
SOURCES
Non – renewable resources are those resources which once used up
cannot be replenished in a short period of time.
Non – renewable resources of energy are also called convectional
sources of energy.
Since these energy resources get exhausted they are also known as
exhaustible sources of energy.
Non –
renewable
Energy
Sources
COAL PETROLEUM
NUCLEAR
FUELS(URANIUM)NATURAL
GAS
5. RENEWABLE ENERGY SOURCES
Renewable energy sources can be replenished in a short
period of time and can be used again to generate energy.
These energy resources are also known as non –
convectional, inexhaustible and alternative sources of
energy.
Renewable
Energy
Sources
WOOD
GEOTHERMAL
ENERGY
TIDAL ENERGY
WIND ENERGY
7. What is a good source of energy?
We can find out whether a given source of
energy is good or not by the following
qualities of a good energy resource.
A good energy resource is one:
Which would do a large amount of work per
un it mass(or per unit volume).
Which is cheap and easily available.
Which is easy to store and transport.
8. CONVECTIONALSOURCES OFENERGY
• The traditional sources of energy
which are familiar to most people are
known as convectional sources of
energy.
EXAMPLES-wood, coal , petroleum ,
natural gas, etc.
9. FOSSIL FUELS
• A natural fuel formed deep under the earth
from the pre-historic remains of living
organisms is called fossil fuels.
• Coal, petroleum and natural gas are fossil
fuels.
• These are the main sources of energy for
generating electricity in power plants.
10. COAL
Coal is a complex mixture of compounds of
carbons, hydrogen and oxygen, and some
free carbon.
A lot of heat is produced during the
burning of fuel which makes it a good fuel.
11. PETROLEUM
The crude oil petroleum is a complex
mixture of several solid, liquid and
gaseous hydrocarbons mixed with water,
salt and earth particles.
The fractional distillation of petroleum
gives us the fractions which can be used
as fuel: petroleum gas, petrol, diesel,
kerosene and fuel oil.
A petroleum refinery
12. NATURAL GAS
Natural gas mainly consists of methane, with small
quantities of ethane and propane.
Natural gas occurs deep under the crust of earth along
with petroleum deposits.
Natural gas is formed under the earth by the
decomposition of vegetable matter lying under the
water. This decomposition is carried out by anaerobic
bacteria.
13. A power plant in which fuel is burnt to produce heat energy
which is converted into electrical energy is known as thermal
power plant.
Large amount of fossil fuels are burnt each day in power
stations to heat up water to produce steam which further
runs the turbines to generate electricity.
THERMAL POWER PLANT
14. HYDRO POWER PLANTS
A power plant that produces electricity by flowing water to rotate
turbines is called hydro power plant.
Hydro power plants convert the potential energy of falling water into
electricity.
Since there are few water falls which could be used as a source of
potential energy, hydro power plants are associated with dams.
15. Working of Hydro Power Plants
In order to produce hydel electricity, high-rise
dams are constructed on the river to obstruct the
flow of water and thereby collect water in large
reservoirs.
The water level rises and in this process the
kinetic energy of flowing water gets transformed
into potential energy.
The water from the high level in the dam is
carried through pipes, to the turbine, at the
bottom of the dam.
Since the water in the reservoir would be refilled
each time it rains, hydro power is a renewable
source of energy.
17. Improvements in the Technology for Using
Convectional Sources of Energy
BIO MASS
Biomass includes wood, agricultural wastes and cow
dung.
Since the fuels like wood, agricultural wastes and
cow dung are all plant and animal products , they
are called biomass or biofuels.
Biomass is a renewable source of energy.
18. The Case of Wood and
Charcoal
Wood is a biomass. When wood is burnt, heat is produced. So,
wood has been used as a fuel for a long time.
Disadvantages of using wood as a fuel:
i. the burning of wood produces a lot of smoke which pollutes
air.
ii. the calorific value of wood is low. This means that wood
produces less heat per unit mass , on burning.
19. Due to the improvement in the technology for using the
convectional sources of energy, wood can be converted into a
much better fuel called charcoal.
When wood is burnt in a limited supply of oxygen, water and
volatile materials present in it get removed and charcoal is left
behind as the residue.
Charcoal burns without flames, is comparatively smokeless and
has a higher het generating ability.
20. Cow dung is biomass. Cow dung is the excreta of
cattle animals such as cows and buffaloes.
Disadvantages of using cow dung directly as a
fuel:
i. Cow dung contains important nutrients which are
needed by the sol. So, burning of cow dung in
the form of cow dung cakes destroys the useful
nutrients which can be otherwise used as a
manure.
ii. Cow dung cakes produces a lot of smoke on
burning which causes air pollution.
iii. Cow dung cakes do not burn completely, they
produce a lot of ash as a residue.
iv. Cow dung cakes have low calorific value.
The Case of Cow Dung and
Biogas
21. Since there are many disadvantages in using cow dung as a
fuel directly, it is better to prepare biogas from cow dung.
Only the organic matter of cow dung is decomposed and
converted into biogas.
When used in this way, cow dung
gives us a double advantage :
it gives us a clean fuel called biogas
the spent cow dung can be used as a manure because it
still contains elements like nitrogen and phosphorus.
BIOGAS PLANT
22. BIOGAS PLANT
A biogas planthas a dome shapeddome like structure built with bricks.
A slurry of cowdung and water is made in the mixing tank fromwhere it is
fed intothe digester.
The digester is a sealedchamber in which there is no oxygen.
Anaerobicmicro organisms break down complex compounds of the cow
dung slurry.
It takes a fewdays for the decompositionprocess to complete andgenerate
gases like methane, carbondioxide, hydrogenand hydrogensulphide.
The biogas is storedin the gas tank above the digester fromwhich they are
drawnthrough pipes for use.
24. Advantages of Bio Gas
Bio gas is an excellent fuel as it contains up to 75% methane.
It burns without smoke, leaves no residue like ash in wood,
charcoal and coal burning.
Its heating capacity is high.
Bio gas is also used for lighting.
The slurry left behind is removed periodically and used as an
excellent manure.
The large scale utilization of bio waste and sewage material
provides a safe and efficient method of waste disposal besides
supplying energy and manure.
25. WIND ENERGY
The uneven heating of the landmass and water
bodies by solar radiation generates air movement
and causes wind to blow.
The kinetic energy of the wind can be used to
work.
The energy of the wind is harnessed by using a
windmill.
26. WINDGENERATOR
To generate electricity, the rotary motion of the
windmill is used to turn the turbine of the electric
generator.
The output of a single windmill is quite small and
cannot be used for commercial purposes.
Therefore a large number of windmills are
erected over a large area, which is known as wind
energy farm.
The wind energy output of each windmill is
coupled together to get electricity on a
commercial unit.
WIND ENERGY FARM
27. Advantages of Wind Energy
An important advantage of using wind energy for generating
electricity is that its use does not cause any air pollution.
Wind energy is a renewable source of energy and it will never
get exhausted .
The increased use of wind energy will help us conserve fossil
fuels so that they last longer.
28. Limitations of Using Wind Energy
The wind energy farms can be established
only where wind flows for most parts of the
year.
The wind speed should be higher than 15
km/h to maintain the required speed of the
turbine.
The wind energy farms require a large area
of land.
The setting up wind energy farms is very
expensive.
29. ALTERNATIVE SOURCES OF ENERGY
(Non- convectional sources of energy)
SOLAR ENERGY
The energy obtained from the sun is called solar energy.
The sun has been radiating an enormous amount of energy at
the present rate for nearly 5 million years and will continue
radiating energy at that rate for about 5 billion years more.
Only a small part of solar energy reaches the outer layer of the
earth’s atmosphere.
Nearly half of it is absorbed while passing through the
atmosphere and rest reaches the surface of the earth.
30. SOLAR COOKER
The solar cooker is a device which is used to
cook food by utilizing the heat energy
radiated by the sun.
A solar cooker consists of an insulated metal
box which is painted all black from inside.
There is a thick glass sheet cover over the
box and a plane mirror reflector is also
painted black from outside.
The metal containers are then placed inside
the solar cooker box and covered with the
31. SOLAR CELLS
Solar cell is a device which converts solar
energy directly into electricity.
A solar cell develops a voltage of 0.5-1 V and
can produce about 0.7 W of electricity when
exposed to the sun.
A large number of solar cells are combined in
an arrangement called solar cell panel that
can deliver enough electricity for practical
use.
SOLAR CELL PANEL
32. Advantages of Solar Cells
The main advantage is that they do not have any moving parts,
require almost no maintenance and work quitesatisfactorily
without the use of any light focusing device.
Another advantage is that they can be set up in remote,
inaccessibleand very sparsely inhabited areas where the laying
of usual power transmission lines is difficult and expensive.
33. Disadvantagesof SolarCells
The main disadvantage of solar cells
is that they are expensive.
The special grade silicon needed for
making solar cells is expensive.
Silver wire used to interconnect solar
cells for making solar cell panels is
very expensive.
The entire process of making solar
cell is also very expensive.
34. ENERGY FROM THE SEA
• The energy from the sea is obtained in
mainly three forms:
i. TIDAL ENERGY
ii. WAVE ENERGY
iii. OCEANTHERMAL ENERGY
35. TIDAL ENERGY
The riseof water due to gravitational pull of the moonis called “hightide”
whereas the fall of sea water is called “low tide”.
The enormous movement of water betweenhightides and low tides provides a
very large source of energy in thecoastal areas of the world.
The tidal energy can be harnessed by constructing a tidal barrage or tidal dam
acrossa narrowopening to the sea.
A turbine fixedat the opening of the damconverts tidal energy to electricity.
The tidal energy is not likely to be a source of potential energybecause there are
only a few sitesaroundthe worldwhich are suitable for building tidal dams.
36. Due to the blowing of wind on the surface of
sea, very fast sea-waves move un its surface.
Due to their high speed, sea waves have a lot
of kinetic energy in them.
The energy of moving sea waves can be used
to generate electricity.
A wide variety of devices have been
developed to trap sea wave energy to turn
turbines and drive generators for the
production of electricity.
37. OCEAN THERMAL ENERGY
The water at the surface of the sea or ocean is heated by the sun
while the water in deeper sections is relatively cold.
This difference in temperature is exploited to obtain energy in
thermal energy conservation plants.
These plants can operate if the temperature difference between the
water at the surface and water at depths up to 2 km is 20° C.
The warm surface water is used to boil a volatile liquid like
ammonia.
The vapours of the liquid are then used to run the turbine of the
generator.
The cold water from the depth of the ocean is pumped up to cool
the used up vapours and convert them again to liquid.
39. GEOTHERMAL ENERGY
Geothermal energy is the heat energy from the
rocks present inside the earth.
Due to geological changes, molten rocks formed
in the deeper hot regions of earth’s crust are
pushed upward trapped in certain regions called
hot spots.
When underground water comes in contact with
the hot spot, steam is generated.
The steam trapped in rocks is routed through a
pipe to a turbine and used to generate
electricity.
41. NUCLEAR ENERGY
Nuclear energy is generated by theprocess of
nuclear fission.
The nucleus of a heavy atom(such as uranium,
plutoniumor thorium) , when bombarded withlow
– energy neutrons, can be split apart into lighter
nuclei.
When this is done a tremendousamountof energy is
released if themass of the original nucleusis just a
little more thanthesum of themasses of the
individual products.
43. ENVIRONMENTAL CONSEQUENCES
Some environmental consequences ofthe increasing demand ofenergyarethe
following:
i. Thecombustion offossil fuels isproducing acidrain.
ii. Theburning of fossil fuels is increasingthe amountof greenhouse gas carbon
dioxide in the atmosphere.
iii. The cutting down oftrees for firewoodis causing soil erosionand destroying
wildlife.
iv. Theconstruction ofhydropower plants isdisturbingecological balance.
v. Nuclearpower plants areincreasing radioactivityin the environment.
44. How Long Will Energy ResourcesLast
It has been estimated that the world’s
known estimated coal reserves are expected
to last for another 200 years compared to
around 40 years for the known petroleum oil
resources and around 60 years for the
known reserves of natural gas.
We can assure a constant supply of energy
by replacing the trees we cut by using bio
mass.
