03.sources of Energy
03.sources of Energy
03.sources of Energy
UNIT - 3
SOURCES OF ENERGY
We do different activities in our daily life. We run vehicles, machines, motors and others, for this all
activities, we need energy. Energy is capacity to do work. Due to increase in population growth,
urbanization and industrialization, the demand of energy is increasing day by day. So in this chapter we
will discuss:
Types of sources of energy, energy crisis, alternative sources of energy and conservation of energy.
The substances that react chemically with another substances to produce heat or produce heat by nuclear
reaction are called fuels.
Coal, petroleum, solar, nuclear fuel, biomass are some examples of fuel.
On basis of consumption, the sources of energy are of two types:
Primary sources of energy:
The sources of energy which are used in the same form in which they occur in nature are
primary sources of energy. Examples; Wood, coal, natural gas, solar energy
Secondary sources of energy:
The sources of energy which are derived from the primary sources of energy are called
secondary sources of energy. Examples; petroleum products, hydroelectricity,
SOURCES OF ENERGY
I. The sources of energy that can be used I. The sources of energy that can not be
again and again and do not get used again and again and get exhausted
exhausted are called renewable sources are called non-renewable sources of
of energy. energy.
II. They are environment friendly. II. They are not environment friendly.
III. They can not be stored. III. They can be stored.
IV. They do not cause pollution. IV. They cause pollution.
V. Examples: Hydroelectricity, Solar V. Examples: Petroleum products, nuclear
energy, Biomass fuel, tidal energy, wind energy, coal
energy, geothermal energy.
SOURCES OF ENERGY
Fossils Fuels:
The sources of energy obtained by the decomposition of dead bodies of plants and
animals that lived thousands and millions of years ago are called fossil fuels.
They are of two types:
Fossil Fuels
E = mc2
Propounded by: Albert Einstein in 1905 AD
Symbol Meaning
E = Amount of energy produced
m = mass of substance
c = velocity of light
It explains that a large amount of energy can be produced by destruction of small amount of mass.
Example: Let
Mass of substance = m = 1 gm = 1/1000 = 10-3 kg
velocity of light = c = 3 x 108 m/s2
Then, Amount of energy produced
E = mc2 = 10-3 x (3 x 108)2
= 10-3 x 9 x 1016
= 9 x 1013 Joules of energy
Advantages of Nuclear energy: SOURCES OF ENERGY
A large amount of energy can produced from small amount of raw material.
It can be produced according to desire and demand.
It can be produced in industrial scale
Disadvantages of Nuclear energy:
It requires huge capital and highly skilled man power to established and maintain the nuclear
power plant.
It produces radiations like α-rays, β-rays, γ-rays which are very harmful for living beings on
earth.
There are radioactive by-products of nuclear reaction which are difficult to dispose on any part
of earth.
Radioactive elements:
The radioactive elements are the unstable isotopes that releases subatomic particles or energy as
they decay. They produce harmful radiations like α-rays, β-rays, γ-rays.
Examples: Uranium (92), Plutonium (94), Americium (95)
Solar Energy: SOURCES OF ENERGY
The heat and light energy obtained from the sun is called Solar energy
Sun:
Mass: 1.99 x 1030 kg
Diameter: 1,392,000 Km
Surface temperature: 57000C
Inner core temperature: 1.3 x 107 0C
Source of energy on Sun: Thermonuclear Fusion
Amount of energy produced on Sun: 4 x 1026 Joules per second.
Amount of energy received on earth’s surface: 1.4 kW per square kilometer.
Conditions for nuclear reactions on Sun:
i. There is large abundance of hydrogen gas on sun.
ii. There is extreme temperature required for splitting of hydrogen into protons and electrons.
iii. There is very high pressure required for combination of protons
iv. There is presence of helium gas formed by combination of hydrogen.
How energy is produced on sun? SOURCES OF ENERGY
Energy is produced on sun by thermonuclear fusion
reaction.
1H
1 + 1H1 1H
2 + 1 eo + Δ
1H
2 + 1H1 2He
3 +Δ
2He
3+
2He
3
2He
4 + 21H1 + Δ
41 H 1 2He
4 + 21eo + Energy
Where
H1 - Hydrogen atom, H2 – Deuterium, He3 - Helium-3
1 1 2
Fossil fuels are obtained from dead bodies of plants and animals that lived
thousands and millions of years ago. Animals depend upon plants for their
food and plants prepare their food from solar energy so fossils fuels are
indirect outcome of solar energy.
SOURCES OF ENERGY
Energy Crisis:
The future scarcity of non-renewable sources of energy due to its over exploitation is called
energy crisis. Energy Consumption
Present situation of energy consumption: 40%
35% 34%
Coal: 27%
30%
27%
Mineral oil: 34% 25% 24%
Hydroelectricity: 7% 15%
5% 4% 4%
Others 4%
0%
Causes of energy crisis: Coal Mineral Oil Natiral Gas Hydroelectricity Nuclear Energy Others