This document discusses various sources of energy. It describes conventional/non-renewable sources such as fossil fuels like coal, petroleum and natural gas which are formed over millions of years from remains of plants and animals. Nuclear energy from uranium fission or fusion is also considered non-renewable. Non-conventional/renewable sources mentioned include solar, wind, hydroelectric, tidal and geothermal energies which are naturally replenished. The document provides details on formation of fossil fuels and how different renewable sources like solar, wind and tidal are harnessed to generate energy.

1. IPE 301E: Fundamental of Mechanical Engineering
Dr. M. Muhshin Aziz Khan
Professor, Dept. of IPE, SUST
Sources of energy

2. Sources of Energy
 Energy
 Energy broadly means the
capacity of a physical system to
 do work and
 produce change.
 Used in science to describe how
much potential a physical
system has to make change.
 Energy exists in everybody
whether they are human beings
or animals or non living things.
 Energy is intimately related to
power.
 Any form of energy can be
converted into another form.
However, the total energy will
remain the same.
 Energy is found in different
forms, such as light, heat,
sound and motion.
 Forms of energy can all be put
into two categories:
 kinetic and
 potential.

3.  Characteristics of Good Sources
 It should have a high energy
output per unit mass or
volume.
 It should be easily available.
 It should be easy to store and
transport.
 It should be economical.
 Sources of energy
There are two main sources of
energy:
 conventional or nonrenewable
 nonconventional or renewable
 Conventional Source
 A natural source that cannot
be remade or regrown at a
scale comparable to its
consumption.
 If exhausted, cannot be
replenished in a short period
of time (within a human life
span)
 Fossilized fuels (as it
takes millions of year to
form and cannot be
replaced as fast as it is
being consumed!)
 Nuclear energy (as once
uranium is used, it is
gone!)
Sources of Energy

4. Conventional Sources
 Fossil Fuels
 Coal, petroleum and natural gas are
called fossil fuels.
 Formed inside the earth from the
remains of plants and animals after
millions of years.
 Fossil fuels are non renewable
sources of energy.
 These should be used with care
and caution to let them last long.
 Disadvantages of fossil fuels
 Burning of fossil fuels release gases
and harmful particles which causes
air pollution.
 Burning of fossil fuels release acidic
oxides of sulphur and nitrogen which
causes acid rain
 Harmful for living organisms,
affects soil and water, causes
damage to buildings, corrosion of
metals etc.
 Burning of fossil fuels release a
large amount of carbon dioxide gas
which increases the temperature of
the atmosphere and causes global
warming (green house effect).
 Advantages of fossil fuels
 Available in highly concentrated
form
 Easy to store
 Reliable supply
 Lower cost per unit of energy
produced as the technology is
matured

5. Fossil Fuels
Coal: How is it made???
Before the dinosaurs,
many giant plants died
in the swamp
Over millions of years,
the plants were buried
under water and dirt
Heat and pressure
turned the dead plants
into coal.

6. Conventional Sources
Oil and Gas: How are they made???
Tiny sea plants and animals
died and were buried on
ocean floor. Over time, they
were covered by layers of slit
and sand
Over millions of years, the
remains were buried deeper
and deeper.
The enormous heat and
pressure turned them into oil
and gas.

7. Nuclear Energy
 Energy released during nuclear
reactions.
 During nuclear reactions,
 some mass is converted into energy
 a very large amount of energy is
produced during nuclear reactions.
 Nuclear reactions are of two types:
 Nuclear fission
 Nuclear fusion.
 Nuclear fission
 The nucleus of a heavy atom like
uranium, plutonium, etc. splits into
smaller nuclei and releases of a
large amount of energy.
 In a nuclear power plant the heat
energy produced by a controlled
nuclear fission chain reaction is
used to produce steam which
rotates the turbines of generators
to produce electricity.
 Nuclear fusion
 small nuclei fuse together to form
a heavier nucleus with the release
of a very large amount of energy.
 The energy of sun is produced by
the fusion of hydrogen nuclei to
form helium nucleus.
 It is also used to make the
hydrogen bomb.
 Advantages of nuclear energy
 It produces a very large amount of
energy per unit mass than any
other source of energy.
 If safety measures are taken, it is
more environment friendly than
fossil fuels.
 Disadvantages of nuclear energy
 The cost of a nuclear reactor is
very high.
 The availability of nuclear fuel is
limited.

8. Nonconventional or Renewable Sources
 Renewable Sources
 Sources of energy which are
being produced continuously in
nature and inexhaustible.
 If consumed, these are
naturally replenished on a
human timescale.
 Renewable sources are those
sources which are unlimited.
 Solar, wind, hydropower, tidal and
geothermal etc. are the
renewable sources of energy.
 About 16% of global final energy
consumption comes from
renewable,
 10% coming from
traditional biomass
 3.4% from hydroelectricity
 New renewable (small hydro,
modern biomass, wind, solar,
geothermal, and biofuels)
accounted for another 3% and
are growing very rapidly.
 The share of renewable
in electricity generation is
around 19%,
 16% of global electricity
coming from hydroelectricity
 3% from new renewable

9. Renewable Sources
 Solar Energy
 Energy obtained from the sun in the
form of heat and light.
 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
photovoltaic cells to generate
electricity.
 This energy comes from nuclear
fusion reactions that take place
deep inside the sun.
 Hydrogen nucleus fuse into
helium nucleus.
 Energy released from these
reactions flow out from the sun
and escape into space.
 It is cheaper to make electricity
using solar energy rather than coal
and other things.
 Advantages
 Doesn’t produce Carbon dioxide.
 Have minimal impact on
environment.
 Disadvantages
 It is not constant, it depends on
weather conditions, time, and
location.

10. Renewable Sources
 Wind Energy
 Wind energy is believed to be
 five times total current global
energy production
 40 times current electricity
demand.
 Energy obtained from the airflow.
 Kinetic energy of the wind is
converted into mechanical or
electrical energy.
 Windmill converts kinetic energy
in to mechanical energy to do
mechanical work like lifting water
from the well, grinding grains in
the flour mills etc.
 Wind turbine converts kinetic
energy to electrical energy by
turning the generator.
 A single wind turbine produces
only a small amount of electricity.
 Minimum wind speed requirement is
15 km/h.
 Areas where winds are stronger
and more constant are preferred
locations for wind farms.
 Offshore resources experience
wind speeds of ~90% greater than
that of land.
 Wind power is growing at the rate of
30% annually,
 with a worldwide installed
capacity of 157,900 MW.

11. Renewable Sources
 Wind Energy
 Advantages
 It is a renewable source of
energy.
 It does not cause pollution.
 The recurring cost is less.
 Once the wind turbine is built,
wind power produces no green
house gases during operation.
 Disadvantages
 Wind is not available at all
times.
 Wind turbines stop working if
there is no wind.
 A minimum wind speed of 15
km/h is required.
 Speed and direction of wind
unreliable.
 It requires a large area of land.

12. Renewable Sources
 Tidal Energy
 Energy obtained by making use of the
water movement from a high tide to a
low tide.
 The periodic rise and fall of sea
level caused by gravitational pull of
the sun and the moon.
 They arise twice a day in Mid-
Ocean.
 The vertical movement of water during
high tide and low tide is used to turn
the turbines and generate electricity.
 Water on high tide is first trapped in a
artificial basin by constructing a tidal
barrage and then allowed to escape on
low tide.
 Advantages
 An inexhaustible source of energy.
 Environment friendly source of
energy and doesn't produce
greenhouse gases
 Disadvantages
 Barrages across river mouths are
expensive to build and disrupt
shipping.
 Very few ideal locations for
construction of plant.
 They are too localized to coastal
regions only.

13. Renewable Sources
 Hydro Energy
 It is the most widely used form of
renewable energy.
 Energy obtained from running water of
the river using various methods.
 Potential energy i.e. water from the
river is first captured and stored by
constructing dams.
 Electrical power is produced by
making use of the gravitational
force of falling or flowing water.
 Damless hydro systems derive kinetic
energy from rivers and oceans without
using a dam.
 Advantages
 Flowing water is a renewable
source of energy.
 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.