MET458

Advanced Energy Engineering

Module - I

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 Basic Concept of Energy
• The word is used with many different connotations, but in
physics, it has a very definite meaning.
• Energy is the capacity of a physical system to perform work
[Energy is the capacity for doing work, generating heat and
emitting light]

Work = Force X Displacement along the direction of force

Law of conservation of energy states that the total amount of
energy in a closed system (like earth) remains a constant. It may
change from one form to another, but the total remains a
constant.
A system may possess energy even when no work is being done.
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3
Since energy is measured by the total amount of work that the
body can do, energy is expressed in the same unit of work.
 Unit of Energy

Joule:
equal to the energy transferred to (work done on) an object
when a force of one Newton acts on that object in the
direction of its motion through a distance of one metre (1
N⋅m).
It is also the energy dissipated as heat when an electric current
of one ampere passes through a resistance of one ohm for one
second.
The work required to produce one watt of power for one second,
or one watt-second (W⋅s) (1kWhr = 3.6 MJ).
One joule in everyday life represents approximately the
amount of electricity required to light a 1 W 7
LED for 1 s.
 Unit of Energy
Calorie: amount of energy needed to raise the temperature of
one gram of water by 1 0C at a pressure of one
atmosphere.

Thermochemical calorie:
the amount of energy exactly equal to 4.184 joules.
= 4.184 J

the amount of energy required to warm one gram of air-free water from 3.5 to
4°C calorie: ≈ 4.204 J
4.5 °C at standard atmospheric pressure.

the amount of energy required to warm one gram of air-free water from 14.5 to
15°C calorie: ≈ 4.1855 J 15.5°C at standard atmospheric pressure. Experimental values ranged from
4.1852 to 4.1858 J.

the amount of energy required to warm one gram of air-free water from 19.5 to
20°C calorie: ≈ 4.182 J
20.5°C at standard atmospheric pressure.
1⁄100 of the amount of energy required to warm one gram of air-free
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water
Mean calorie: ≈ 4.190 J from 0 to 100°C at standard atmospheric pressure.
 Sources of Energy
There are SIX sources of useful energy utilised by human beings
on planet Earth.
They are:
(i)the Sun (thermal and electric);
(ii)geothermal energy from cooling, chemical reactions and
radioactive decay in the Earth (thermal and electric);
(iii)the gravitational potential and planetary motion among Sun,
Moon and Earth;
(iv)chemical energy from reactions among mineral sources;
(v) fossil fuels such as coal, petroleumproducts and natural
gases (thermal and electric); and
(vi)nuclear energy from nuclear reactions on the Earth.
Renewable energy is obtained from sources (i), (ii) and
(iii), whereas sources of non-renewable energy are (iv),
(v) and (vi)
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 Classification of Energy
• Based on nature of availability of energy
n Primary resources secondary resources
s
• Based on utilization of energy
t Conventional energy Non -conventional energy
e

• Based on availability of energy

,
Renewable energy Non-Renewable energy

• Based on commercial application of energy

Commercial energy Non-commercial energy
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 Renewable &Non-renewable Energy
• Renewable energy is energy obtained from naturally
repetitive and persistent flows of energy occurring in the
local environment.
An obvious example is solar (sunshine) energy that ‘persists’
and ‘repeats’ day after day, but is obviously not constant but
variable.

In contrast,
• Non-renewable energy is energy obtained from static stores
of energy that remain underground unless released by human
interaction.
Examples are nuclear fuels and the fossil fuels of coal, oil, and
natural gas. With these sources, the energy is initially an
isolated energy potential and external action is required to
initiate the supply of energy for practical purposes.
 Renewable &Non-renewable Energy

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 Conventional Energy resources
• Fossil fuel energy

(a) Coal (b) Petroleum (c) Natural gas

❖Mixture of carbon, ❖Crude petroleum is refined by ❖Product of petroleum
hydrogen and oxygen fractional distillation. mining
❖Heating of coal gives coal ❖ Heated up to 4000C in a furnace. ❖Occurs alone or along
gas, Ammonia, coal tar and ❖Vapour is passed through a tall with petroleum deposits.
coke fractioning columnand is cooled ❖Methane (95%), Ethane
❖Coke is 98% carbon and is ❖Products: LPG (<400C), Petrol (40 and propane
smoke free to 170 0C), Kerosene (170 to 2500C),
❖ CNG and LNG
❖ Types: Peat(60% C), Diesel (250 to 3500C), Fuel oil (for boilers
Lignite (70% C), Bituminous and furnaces) (350 to 4000C) and Residual
(80% C), Anthracite (90% C) oils (asphalt, paraffin wax, lubrication
oils)

• Hydraulic energy
• Nuclear energy 13
 Non conventional energy resources
• Solar energy
• Wind energy
• Tidal energy
• Wave energy
• Geothermal energy
• biomass energy
(a) Biogas (b) Bio fuel (c) Solid biomass
❖Methane from ❖Bio deiesel and ethanol ❖Combustion, Gasification
waste derived from plants and Anaerobic digestion
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 Global
Energy Scenario

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 Tipping the energy world off its axis
Four large-scale upheavals in global energy set the scene for the new
energy outlook:
1.The United States is turning into the undisputed global leader
for oil & gas. 2.Solar PV is on track to be the cheapest source of
electricity in many
countries.
3.China’s new drive to “make the skies blue again” is recasting
its role in energy.
e
4.The futureis electrifying, spurred by cooling,
electric vehicles & digitalization.
These changes brighten the prospects for affordable, sustainable
energy & require a reappraisal of approaches to energy security.
There are many possible pathways ahead & many potential pitfalls if
governments or industry misread the signs of change.
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 Global Energy Resources
Total Energy supply: 87% Non renewable sources Oil:
Transportation, heat generation and chemical industry Natural gas:
Heat, Electricity generation and chemical industry Coal: Electricity
generation and steel production

Uranium: Electricity generation

World oil reserves estimated Why? Vigourous

➢ 300 billion barrels in 1963
exploration
➢ 998 billion barrels in 1994 Current reserves are
➢ 1016 billion barrels in 2000 enough for 52 to 54 years
going at the current rate
➢ 1300 billion barrels in 2014 of production
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 Global Energy Resources - Oil
OPEC contributes 81.5% of crude oil reserves
• Venezuela-24.9%, Saudi-22.1%,Iran-13.1%, Iraq-11.9%,
Kuwait-8.4%, UAE-8.1%, libya-4%, Nigeria-3.1% and
Qatar-2.1% and Algeria, Angola, Ecuador
Total: 1206 billion barrels (2014 estimate)
Non OPEC countries
• Canada (175 billion barrels), Russia (80 billion barrels),
Kazakhstan (30 billion barrels), USA (25 billion barrels),
China (25.4 billion barrels), EU (14 billion barrels)

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Global Energy Resources – Natural Gas

• World reserves –187.1 trillion cubic metres (tcm)

• Iran 34 tcm, Russia 32.6 tcm and Qatar 24.5 tcm
• Shale gas to be added

Global Energy Resources – Coal

• Enough reserve to last 110 years at current rate of
production.
• 73% of total coal is in 5 countries.
• US - 26.6%, Russia - 17.6%, China - 12.8%, Australia
- 8.6%, India - 6.8%
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Global Energy Resources – Uranium
• Australia 29%, Kazakhstan 12%, Russia 9% and
Canada 8% .

Global Energy Resources – Hydro-electric

Predominant form of renewable energy. At present
supplies 20% of worlds electricity.
Main Contributors:
China 27.4%, Canada 9.8%, Brazil 9.5%, US
6.7%,Russia 4.5%, Norway 3.5%, India 3.4%

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The future is electrifying

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EVs are on the way, but oil demand
still keeps rising

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A new strategy for energy & sustainable
development

➢875 million electric vehicles ➢2times more efficient than

➢3250GW global solar PV today
capacity ➢ 580bcm additional gas demand
Only 15% additional investment is required to 2040 to achieve the Sustainable
development scenario, with two-thirds of energy supply investment going to23
electricity generation & networks
 Indian Energy Scenario
INDIA IS THE THIRD LARGEST PRODUCER OF ELECTRICITY IN THE
WORLD.

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 Global Energy demand & supply
• USA – 11.4 kWh per person (population 4.59%)
(25% consumption in 2000-> 18.5% in 2011)
• Japan – 6 kWh per person
• Germany – 6 kWh per person
• China – 1.6 kWh per person (population 19.6%)
(10.8% consumption in 2000-> 21.3% in 2011)
• India – 0.7 kWh per person
(3.2% consumption in 2000-> 4.6% in 2011)
• Bangladesh – 0.2 kWh per person (lowest)
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Renewable Energy demand &
supply
Renewable energy comes from natural resources such as sunlight,
wind, rain, tides and geothermal heat, which are naturally
replenished.
16% of global energy consumption comes from renewables, with
10% coming from traditional biomass, mainly used for heating,
and 3.4 % from hydroelectricity.
New renewables (small hydro, modern biomass, wind, solar,
geothermal, and biofuels) accounted for another 2.8% and are
growing very rapidly.
The share of renewables in electricity generation is around 19%,
with 16% from hydroelectricity and 3% from new renewables.
While many renewable energy projects are large-scale, they are also
suited to rural areas, where energy is crucial in human
development. 31
Renewable Energy demand & supply
S
Small solar PV systems provide electricity to a few million N
households, and micro-hydro configured into minigrids serves 1
2
many more. 3
4
Over 44 million households use biogas made in household-scale 5
digesters for lighting and/or cooking, and more than 166 6
million households rely on a new generation of more-efficient 7

biomass cookstoves. 8

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Climate change concerns, coupled with high oil prices, and 1
increasing government support, are driving increasing 1
1
renewable energy legislation, incentives and commercialisation. 1
1
According to IEA in 2011, solar power generators may produce 1
most of the world’s electricity within 50 years, reducing the 1
emissions of greenhouse gases that harm the environment.
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 India’s Energy demand & supply
• Oil reserves – 125 million metric tonnes & consumption –2
million barrels a day per capita S

• Natural gas reserves – 38 Trillion cubic feet (Tcf) & N

consumption – 752 billion cubic feet

3rd largest electricity producer with 4.8% global share.
• 281.4 GW capacity ( in 2015)-> 28% renewable & 72 non
renewable.
• Solar resources-> 4.5 kWh/sq.mile, market potential 30 MW
• Wind-> 845 MW, biomass -> 17000 MW, market potential
3800MW
• Geothermal -> 2000 – 10000 MW, limited market potential
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 Sources of power
y
,
y

h
,

r,
e

o
➢ Prime mover is a machine that transforms energy from thermal or
n
pressure form to mechanical form; typically an engine or turbine.
 Hydel power Small hydel power
plants in Kerala plants in Kerala
y Sl.
No
Name of Station
Installed Capacity
(MW) of station
Sl.
No
Name of Station
Installed Capacity
(MW) of station

1 Idukki 6 x 130 780 1 Kallada 2x7.5 15

2 Sabarigiri 4 x 55 + 2x 60 340 2 Peppara 1x3 3

3 Idamalayar 2 x 37.5 75 3 Malankara 3x3.5 10.5

4 Madupatty 1x2 2
4 Sholayar 3x18 54
5 Malampuzha 1x2.5 2.5
5 Pallivasal 3 x 5+ 3x7.5 37.5
6 Lower Meenmutty 1x0.5 + 2x1.5 3.5
6 Kuttyadi 3x25 75
7 Chembukadavu - 1 3x0.9 2.7
7 Kuttyadi Extension 1x50 50
8 Chembukadavu - 2 3x1.25 3.75
Kuttyadi Additional
8 2x50 100 9 Urumi -1 3x1.25 3.75
Extension
10 Urumi -2 3x0.8 2.4
9 Panniar 2 x 16.2 32.4 11 KTR 3x1.25 3.75
10 Neriamangalam 3 x17.55 52.65 12 Poozhithode 3 x 1.6 4.8
11 NES 1x25 25 13 Ranni-Perinadu 2x2 4
12 Lower Periyar 3 x 60 180 14 Peechi 1x1.25 1.25
13 Poringalkuthu 4x9 36 15 Vilangad 3x2.5 7.5
14 PLBE 1x16 16 16 Chimmony 1x2.5 2.5
15 Sengulam 4 x 12.8 51.2 17 Adyanpara 2x1.5 +0.5 3.5
16 Kakkad 2x25 50 Sub Total(SHEP) 31Nos 76.4

Sub Total(HEP) 49 Nos 1954.75 Total (Hydel) 80 Nos 2031.15

 Thermal power IPP(Independent Power
plants in Kerala Producer)
/CPP (Captive Power
plants)
Installed Capacity Installed Capacity
SL.
Name of Station (MW) of station SL. Name of Station (MW)of station
No.
No.
Nos MW
Nos MW
BDPP (Brahmapuram
1 3x21.32 63.96
Diesel Power Plant) 1 Maniyar 3x4 12

2 Kuthungal 3x7 21
KDPP (Kozhikode Diesel
2 6x16 96
Power Project) 3 Ullunkal 2x3.5 7

4 Iruttukanam 3 x 1.5 4.5

Sub Total(Thermal) 13 nos. 159.96
5 Karikkayam 10.5
Wind/ Solar

1 Kanjikode Wind Farm 9x0.225 2.025 6 Mankulam 0.11

2 Kanjikode Solar plant 1 7 Meenvallom 3

8 Kallar 0.05
TOTAL (KSEB) 102 Nos 2194.135

Sub Total 58.16

 Steam power plant

Turbine

Boiler Condenser

Pump

Rankine cycle
A steam power plant using steam as working substance works
basically on Rankine cycle. A steam power plant converts the
chemical energy of the fossil fuels (coal, oil, gas) into
mechanical/electrical energy.
 Steam power plant
To atmosphere

Chimney

Flue gases
Air
Air-preheater Air
Flue gases

Coal/oil
Steam Economiser
Turbine
Ash storage yard Boiler with Flue gases
Generator
super-heater
Condenser

Feed water Cooling

tower
Feed pump

Layout of a steam power plant Pump

Steam Power Plant

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 Components of steam power plant
1. Boiler – Boiler is an equipment to produce steam.

2. Steam turbine – High pressure super heated steam is fed to the steam turbine which
causes turbine blades to rotate. Energy in the steam is converted into mechanical energy
in the steam turbine which acts as the prime mover.

3. Generator – It is coupled with the turbine rotor and converts the mechanical energy of
the turbine to the electrical energy.

4. Condenser – Condenser is a heat exchanger in which cooling water is circulated through

the tubes. The exhaust steam from turbine enters the condenser where it is cooled and
converted to condensate (water). The use of condensers improves the efficiency of the
power plant by decreasing the exhaust pressure of the steam below the atmospheric
pressure. The deposition of the salt in the boiler is prevented with the use of condensate
instead of using feed water from outer source which may contain salt. The use of
condensers reduces the capacity of the feed water cleaning system. Water circulating
through the condenser may be taken from the various sources such as river, or lake. If
sufficient quantity of water is not available the hot water coming out of the condenser
may be cooled in cooling towers and circulated again through the condenser.

5. Economizers – Economizers are devices fitted to a boiler which saves energy by using the
heat energy of exhaust gases from the boiler to preheat the feed water thereby improving
the boiler's efficiency.
 Components of steam power plant
5. Super-heater – Super-heater is a device that heats the steam generated by the boiler
again increasing its thermal energy. It converts wet steam into superheated steam
(high temperature dry steam).

6. Precipitator – Precipitator is a device (dust collector) that removes particles from the
flowing gas.

7. Air pre-heater or air heater – Air pre-heater is used to recover the heat from the boiler
exhaust gases which increases the thermal efficiency of the boiler by reducing the
useful heat lost in the exhaust gases.

8. Deaerator – It is a device used for the removal of air and other dissolved gases from the
feed water to steam generating boilers. A steam generating boiler requires that the
boiler feed water should be devoid of air and other dissolved gases, particularly
corrosive ones, in order to avoid corrosion of the metal.

9. Forced and induced draught fans – The small pressure difference which causes a flow
of gas to take place is termed as a draught. In a forced draught draught system, the
draught is produced by a fan or a blower installed at the base of the boiler forces the
air through the furnace, flues, air pre-heater, economizer, etc. It is a positive pressure
draught. In induced draught system, a fan or blower is located at or near the base of
the chimney creating a partial vacuum so that the products of combustion pass up the
chimney.
 Circuits in a steam power plant
1. Coal and ash circuit – The coal from the storage is fed to the boiler through coal handling
equipments such as belt conveyors. Heat produced by the burning of coal is utilized in converting
water contained in boiler drum into steam at suitable pressure and temperature. Ash resulting from
combustion of coal is removed to the ash storage yard through ash handling equipment.
2. Air and gas circuit – Air taken in from atmosphere through the action of a forced draught (air forced
to flow in by the use of blower) or induced draught (air flowing in due to decreased pressure) fan first
passes through the air pre-heater, where it is heated by flue gases. The hot air then passes through the
furnace. The flue gases after passing over boiler and super-heater tubes, flow through the dust
collector and then through economizer (economizer capture the waste heat from flue gas and transfer
it to the boiler feed-water), air pre-heater and finally they are exhausted to the atmosphere through
the chimney.
3. Feed water and steam circuit – The steam generated in the boiler is supplied to the turbine to
develop mechanical power. The steam coming out of turbine is condensed in the condenser and fed
back to the boiler using feed pump. Some of the steam and water is lost by passing through the
different components. Therefore it is necessary to supply 4 to 5% of total feed water from external
source to compensate the loss.
4. Cooling water circuit – Abundant quantity of water is required for condensation of steam. This is
mostly taken from river. If adequate quantity of water is not available at the plant site a cooling tower
is used.
Advantages of steam power plant
1. Less initial cost as compared to other generatingplants.
2. The capital cost is low compared to hydel plant.
3. Construction time is low.
4. Power generation does not depend on nature’sclimatic condition.
5. Power plant can be located near industrial areas.
6. The fuel used is quite cheap.
7. It can be installed at any place irrespective of the existence of coal.
8. It requires less space as compared to Hydro power plants.
9. Cost of generationis less than that of diesel power plants.
10. Steam power plants are most economical if sited near coal mines and by the
side of river or canal.

Disadvantages of steam power plant

1. Source of fuel i.e., coal reserve all over the world is considered to be fixed and
therefore coal mines are being exhausted. Hence, there is a limit in source of
power.
2. Power generation cost is considerably high compared to hydal plant.
3. Operating cost is more compared to diesel and nuclear power plant.
4. Maintenance cost is high as compared with that of hydro and diesel power
plants.
5. Fuel transportation and handling are difficult.
 Hydro Electric Power Plant
Reservior 1
Dam
Transmitting 2
Water carrying Tower
pipe
3
Trash rack

Anchor
Transformer room

Control room

Transformer

Generator
Tail race
Turbine

Layout of a hydro electric power plant Outlet 44

Hydro Electric Power Plant

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 Components of Hydel Power Plant

1. Catchment area – Whole area behind the dam, draining into a stream or river
across which the dam has beenbuilt.

2. Reservoir –The purpose of the storing of water in the reservoir is to get a

uniform power output throughout the year. A reservoir can be either natural or
artificial.

3. Dam – A dam is any barrier that holds water; the water stored behind the dam is
used to drive turbines that are connected to electrical generators. It acts as an
e artificial reservoir.
a

Based on structure and design, dams are classified as gravity dams, arch dams
and buttress dams.
el

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 Components of hydel power plant

Types of dams
1. Gravity dams –Gravity dams rely on their own weight to hold back
large volumes of water.
2. Arch dams – An arch dam is curved in plan, with its convexity towards
the upstream side. eg. Idukki dam.
3. Buttress dam – A buttress dam is a dam with a solid, water- tight
upstream side that is supported at intervals on the downstream side by
a series of buttresses or supports.

Gravity dam Arch dam Buttress dam 47

 Components of hydel power plant

Dam
Surge tank
Reservoir

Penstock

Power house

Surge tank

6. Trash rack – The function of trash rack is to prevent the flow of debris, sand
and fishes to the turbine.

7. Surge tank –It is a storage reservoir used to absorb the sudden rises of water
pressure, as well as to provide extra water during a drop in water pressure.
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Surge tank
1.

2.

3.
l

4.

5.

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 Components of hydel power plant

8. Turbine – The function of turbine is to act as a prime mover to convert

the potential energy of water in to mechanical energy. It is explained in a
later section in detail.

9. Runner – The runner is a circular wheel on which a series of curved

vanes are mounted. Vanes are so designed that water enters and leaves
the runner without shock.

10. Power house – The powerhouse accommodates prime mover, generator 1

.
(generate electrical power using mechanical power obtained from the
turbine), accessories and control room sometimes transformer also.
Water after passing through the turbine is discharged into a downstream 2
.
called as tailrace, which carries it into the river.
Classification hydro electric power plants
1. Classification with respect to quantity of water available
a) Run-off river plants – Run-of-the-river hydroelectric harvest the
energy from flowing water to generate electricity in the absence of
a large dam and reservoir.
b) Reservoir plants – A reservoir plant is that which has a reservoir
of such size as to allow carrying over storage from wet season to
the next dry season.

2. Classification according to availability of water head

a) High-head hydro-electric plants (head more than 250 m)
b) Medium-head hydro-electric plants (head ranges from 30 m –
250 m)
c) Low-head hydro-electric plants (head is less than 30 m)

3. Classification according to nature of load

a) Peak load plants – The peak load plants are used to supply
power at the peak demand phase.
b) Base load plants – A base load power plant is one that provides
a steady flow of power regardless of total power demand.
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Selection of site for a hydro power plant

1. Water available – The most important aspect of hydro-electric plant is the availability
of water at the site since all other designs are based on it. Therefore the run-off data at
the proposed site must be available.
2. Water-storage – The output of a hydropower plant is non-uniform due to variations in
rain fall. To have a uniform power output, storage is needed so that excess flow at
certain times may be stored to make it available at the times of low flow. To select the
site of the dam; careful study should be made of the geology and topography of the
catchment area to see if natural foundations could be found and put to the best use.
3. Head of water – In order to generate a requisite quantity of power it is necessary that a
large quantity of water at a sufficient head should be available. The level of water in the
reservoir for a proposed plant should always be within limits throughout the year.
4. Distance from load center – Most of the time the electric power generated in a hydro-
electric power plant has to be used some considerable distance from the site of plant.
For this reason, to be economical on transmission of electric power, the routes and the
distances should be carefully considered since the cost of erection of transmission lines
and their maintenance will depend upon the route selected.
5. Access to site – It is always a desirable factor to have a good access to the site of the
plant. This factor is very important if the electric power generated is to be utilized at or
near the plant site. The transport facilities must also be given due consideration.
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 Hydrologic cycle
Precipitation
(Rain, snow, etc. )
Transpiration Evaporation The hydrologic cycle,
from vegetations
also known as the
water cycle describes
the circulation of water
Water table
Ocean in the earth-atmosphere
system.
Hydrologic cycle

1. Precipitation – It includes all the water that falls from atmosphere to earth surface. Precipitation is of two types,
viz., liquid precipitation (rain fall) and solid precipitation (eg. snow).

2. Run-off – Run-off is the part of water cycle that flows over the land as surface water instead of being infiltrated into
soil or evaporating.
a) Surface runoff is that portion of rainfall which enters the stream immediately after the rainfall.
b) Sub-surface runoff is that part of rainfall, which first reaches into the soil and moves laterally without
joining the water - table to the streams, rivers or oceans.
c) Base flow is that part of rainfall which after falling on the ground surface which get infiltrated into the soil
and meets the water table (level below the surface of the ground where water can be found) and flow to the
streams oceans, etc.
Runoff = Surface runoff + Base flow (Including sub - surface runoff)
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ts
Hydrologic cycle
e Precipitation
(Rain, snow, etc. )
of Transpiration Evaporation
from vegetations
ir
o
Water table
Ocean

Hydrologic cycle

– 4. Evaporation – Transfer of water from liquid to vapour state is called evaporation.

5. Transpiration – The process by which water is released to the atmosphere by the plants is
called transpiration.

6. Sublimation – Sublimation results from when pressure and humidity are low. It is not only
ly liquid water that can evaporate to become water vapor, but ice and snow, too. Due to lower
air pressure, less energy is required to sublimate the ice into vapour.
s
 Hydrologic cycle A

Precipitation
1.
(Rain, snow, etc. )
Transpiration Evaporation
from vegetations

2.

Water table
Ocean
3.

Hydrologic cycle 4.
5.
The hydrological cycle can be briefed as 6.
(hydrological equation). I – Q = ∆S;
where, 7.
I = Inflow of water to a given area during any given time period,
Q = Outflow of water from the area during the selected time period,
8.
ΔS = Change in storage of water in a given area during the time period. 9.

This equation states that during a given period, the difference between the 1
total inflow of water and out flow of water must equal the change in storage of
water 1
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 Factors affecting run-off

F a n sh ap e d c at c h m e n t ar ea El o n g at e d c at ch me n t ar ea
Discharge

H yd r og ra p h of fa n sh ap ed
c at c hm en t ar ea
H yd r og ra p h of el on gat ed
c at c hm en t ar ea

Time

1. Topography of catchment area – Steep and impervious areas will produce large percentage of
run-off. The water will flow quickly and absorption losses will be small. The size of catchment
has a definite effect on the runoff. More the area, more will be the runoff. So also, the shape will
have a definite effect on the runoff. In case of a fan-shaped catchment area, the period of the
resulting hydrograph will be less and thus more peak flow may be expected. In case of an
elongated catchment, the period of the resulting hydrograph (graph showing discharge (runoff)
of flowing water with respect to time for a specified time) will be comparatively more and thus
more will be the infiltration losses
and less will be the runoff
 Factors affecting run-off
2. Nature of rainfall – Short and hard showers may produce relatively
little run-off. Rains lasting longer time results in larger run-off.

3. Geology of area – The run-off is very much affected by the types of

surfaces soil and sub-oil, types of rocks, etc. Rocky areas will give
more run-off while pervious soil and sandy soil will give less run-off.

4.Vegetation –Thick vegetation like forest consumes a portion of rain

fall and also acts as a obstruction for run-off.

5. Other climate factors – Other factors such as temperature wind

velocity, humidity, annual rainfall etc., affect the water losses from
watershed (small streams) area.
 Advantages of hydro electric power plants
1. Water source is perennially available. No fuel is required to be burnt to generate
electricity. It is aptly termed as 'the white coal'. Water passes through turbines to
produce work and downstream its utility remains undiminished for irrigation of
farms and quenching the thirst of people in the vicinity.
2. The running costs of hydropower installations are very low as compared to thermal
or nuclear power stations. In thermal stations, besides the cost of fuel, one has to
take into account the transportation cost of the fuel also.
3. The number of operations required is considerably small compared with thermal
power plants.
4. There is no problem with regards to the disposal of ash as in a thermal station.
5. The hydraulic turbine can be switched on and off in a very short time.
6. The hydraulic power plant is relatively simple in concept and self-contained in
operation.
7. Modern hydropower equipment has a greater life expectancy and can easily last 50
years or more. This can be compared with the effective life of about 30 years of a
steam or nuclear station.
8. Modern hydro-generators give high efficiency over a considerable range of load.
d. 9. Hydro-plants provide additional benefits like irrigation, flood control, afforestation,
navigation and aqua-culture.
he 10. Being simple in design and operation, the hydro-plants do not require highly
of skilled workers. Manpower requirement is also low.
11. The cost of land is not a major problem since the hydro-electric stations are
situated away from the developed areas.
58
 Disadvantages of hydro electric power plants
1. Cost of transmission is high since most of the plants are in
remote areas.
2. Hydro-power projects are capital-intensive with a low rate of
return.
3. It takes considerable long time for the erection of such plants.
4. Power generation is dependent on the quantity of water
available, which may vary from season to season and year to
year. If the rainfall is in time and adequate, then only the
satisfactory operation of the plant can be expected
5. Such plants are often far away from the load centre and
ge require long transmission lines to deliver power. Thus the cost
ll. of transmission lines and losses in them are more.
he 6. Large hydro-plants disturb the ecology of the area, by way of
ed deforestation, destroying vegetation and uprooting people.
ak The emphasis is now more on small, mini and micro
ng
hydel stations.
a
es
59
 Diesel power plant
Servicetank Exhaust
Fuel injection pump
e Silencer
er Toatmosphere
Fuelfilter

s Dieselengine
ll
s Generator
Fuel storage tank Pump

Compressedair Hotwater Lubricating Coldwater

Hotoil
of oilcooler Coldoil
Surgetank
Pump
Airfilter
d Heat
s Aircompressor Pump
exchanger
Diesel powerplant
Diesel power plant 1
2
3
4
5

6
7

2
3
4
61 5
 Components of diesel power plant
1. Engine – For electric power generation, four-stroke engines are
predominately used. Horizontal engines are used for comparatively smaller
outputs, while vertical engines with multi-cylinder construction are used
for larger outputs. It is generally directly coupled to the generator.

2. Air supply system – Air from atmosphere after filtering is admitted to the
engine. In large plants supercharger (uses an air compressor that
increases the pressure of air supplied to the engine so that more fuel is
burned and do more work)/turbocharger (uses an air compressor driven
by the exhaust gases to compress the air supplied to the engine increasing
the amount of fuel and air fed into the engine and hence more efficient) is
used to increase the output power.

3. Exhaust system – Exhaust system is used to discharge the engine

exhaust to the atmosphere outside the building. A silencer is incorporated
to reduce the noise level.

4. Fuel system – Fuel is stored in the storage tank is pumped to a smaller

service tank at daily or short intervals. Fuel stored in the service tank is
fed to fuel filter and is finally injected in to the engine.
 Components of diesel power plant
5.Cooling system – Hot water from the engine is carried to the
surge tank. From the surge tank, hot water is fed through the
heat exchanger. In the heat exchanger, cold water from the
cooling towers is circulated which takes away the heat of the
water from the engine. Cold water is then pumped back to the
engine.
6.Lubricating system – It includes the oil pumps, oil tanks, filters,
coolers and pipe lines. Lubricating system provides lubricating oil
to moving parts of the system to reduce the friction and wear and
tear of the engine parts.
7.Starting system – This is an arrangement to start the engine
initially, until firing starts and the unit runs with its own power.
There are mainly three types (1) petrol driven auxiliary engine (2)
use of electric motors (3) use of compressed air from an air
compressor.
8.Governing system – The function is to maintain the speed of the
engine constant respective of load on the plant.
Advantages of diesel thermal power plant
1. Design layout of diesel power plant is simple and cheap.
2. Part load efficiency diesel power plant is very high.
3. Diesel power plant can be started quickly.
4. Maintenance of diesel power plant is easy.
5. Thermal efficiency of diesel is quite higher than steam power
plant.
6. It can also be designed for portable use.
7. Diesel plants can be located very near to the load centers.
Disadvantages of diesel thermal power plant
1. The cost of diesel is very high compared to coal. Hence, the
running cost of this plant is higher compared to steam and hydro
power plants.
2. There is a limitation for size of a diesel engine.
3. Noise pollution is very high.
4. High maintenance and lubrication cost.
5. Capacity of diesel plants is limited and Life is less.
 Nuclear Power Plant
➢ In nuclear power plant, heat energy available from
nuclear fission is used for the generation of steam.

➢ Nuclear fission can be defined as the process, in which

a nucleus is split into two divisions, more or less of equal
mass releasing energy in the form of electromagnetic
radiation and kinetic energy.

➢ The heat produced by fission in the nuclear reactor is

carried out of the reactor by coolant. This heat is used to
generate steam. This heat transfer takes place in a heat
exchanger such as boiler.

➢ The pressurized steam is then fed to a steam turbine

which is connected to a generator.
 Nuclear Power Plant
e
e
e
e
e

,
l
d

e
.
)
r

66
Components of Nuclear power plant
N
1. Nuclear reactor – It is an apparatus in which fi
nuclear fuel is subjected to nuclear fission. 1

2. Heat exchanger – The coolant gives up heat to the

heat exchanger, which utilized for generating steam.
After giving up heat, the coolant is fed back to the
2
reactor.

3. Steam turbine – The steam produced in the heat

exchanger is fed to turbine for doing useful work.
3

4. Generator – The steam turbine drives the generator

which converts mechanical energy in to electric
power.
Components of Nuclear reactor

68
Components of Nuclear reactor
Control rod Control rod

Coolant OUT
Pressure vessel
Reflector

Moderator
Fuel

Neutron
detector
Biological
shield

Coolant in
Components of nuclear reactor
Components of Nuclear reactor
Nuclear reactor is an apparatus in which nuclear fuel is subjected to nuclear
fission.
1. Fuel – Nuclear fuels usually used in the reactors are isotopes (atoms of the
same element having the same numbers of protons, but different numbers of
neutrons) of Uranium and Plutonium. Isotopes like U-233, U-235 and Pu-239
can be fissioned by neutrons of all energies, whereas isotopes U-238, Th-232
(Thorium) and Pu-240 are fissionable by high energy (14 MeV) only. Usually
pellets of fissionable materials are arranged in tubes to form fuel rods.
2. Moderator – Moderator is used to slow down the kinetic energy of fast
moving neutrons. This has to be done as only the slow neutrons maintain the
fission chain reaction. The neutrons collide directly with the moderator and
thus slowed down. Substances like light water, heavy water, carbon,
beryllium are used as moderator.
3. Control rods – Control rods are used to control the nuclear chain reaction. It
is an essential part of a reactor and serves the following purposes .
a) For starting the reactor.
b) For maintaining at that level.
c) For shutting the reactor down under normal or emergency conditions.
Control rods are usually made up of cadmium and boron. Control rods
control the chain reaction by absorbing neutrons.
Components of Nuclear reactor
4. Coolant – Purpose of coolant is to extract heat generated by
the fission process. The various fluids used as coolant are
water (light water /heavy water), gas (Air, CO2, Hydrogen),
and liquid metal cooled reactors etc.

5. Reactor vessel – It is a strong walled container housing the

reactor core, shield and the reflector. It is strongly built so
as to withstand high pressures developed.

6. Reflector – Reflector is used to reduce the loss of neutrons

by reflecting back into the core of the nuclear reactor.
Reflector is generally made of the same material as the
moderator.

7. Shield – Shield prevents the transfer of radiation o the

external world.
Advantages of nuclear power plant
1. No problem of fuel transportation, storage, etc.
2. Less man power is required.
3. It is more economical compared to thermal plant.
4. Power capacity of plant is very high.
5. Capital cost except for reactor is very less.
6. It does not depend up on the condition of the weather.
7. By this process we can conserve the fuels like oil, coal
gases and other by-products.
Disadvantages of nuclear power plant
1. Nuclear radiation causes severe environmental problems.
2. Disposal of radioactive nuclear waste is menace.
3. Varying load conditions are not suitable.
4. Capital cost is very high for the reactor.
 Nuclear Power Plant
Types of reactors
Light water-cooled and moderated reactors (LWR)
using slightly enriched uranium fuel are the type most
commonly used for power production. These reactors
are further divided into :-

1) Pressurized water reactor (PWR) and

2) Boiling water reactor (BWR).

Pressurized Water Reactor (PWR) P
Pressurizer

Turbine
Pressurized heated Steam
water
Heat exchanger
(Boiler)

Reactor

Condenser

Feed
water

Coolant pump Feed water heater Feed water pump

Pressurized water reactor
Pressurized Water Reactor (PWR)

75
Pressurized Water Reactor (PWR)
➢ Pressurized Water Reactor (PWR) make use of two loops viz.,
primary and secondary loops to convert the heat generated by
the fuel into electric power.

➢ In the primary loop, the pressurizer maintains a high pressure

in the water in the range of 150 bar. The pressurized water
(coolant) is circulated in the reactor. Due to the high pressure
of the water, the water does not boil.

➢ The coolant gets heated in the reactor and the hot water enters
the boiler and transfers heat to the feed water in the boiler in
the secondary loop. The transfer of heat is accomplished
without mixing the two fluids, which is desirable since the
primary coolant might become radioactive.

➢ Feed water evaporates and runs the turbine.

) Pressurized Water Reactor (PWR)
Advantages of PWR

1. Because the water used in the high-pressure water

loop is isolated from water in the steam loop, no
radioactive material is contained in the steam.
2. PWR has high power density and has compact size.

Disadvantages of PWR

1. Capital cost is high as high primary circuit requires

strong pressure vessel.
2. In the secondary circuit, the thermodynamic
efficiency of the plant is quite low.
) Boiling Water Reactor (BWR)
Turbine

Concrete shell Thermal shielding

Generator

Uranium fuel

Condenser
Moderator

Feed pump
Coolant water

Boiling water reactor

Boiling Water Reactor (BWR)

In
w
i.e
st
ar
us
79
ex
Boiling Water Reactor (BWR)
➢ In Boiling Water Reactor (BWR), the coolant (water)
used in the reactor absorbs heat produced during
the fission reaction in the reactor.

➢ The fuel used is enriched uranium oxide. Water

evaporates and steam is generated in the reactor
itself. In this type of reactor, there is no need of
separate boiler.
➢

➢ In BWR, the coolant is in direct contact with

turbines, so if a fuel rod had a leak, radioactive ➢

material could be placed on the turbine.

Boiling Water Reactor (BWR)
Advantages of BWR

➢ A major advantage of the BWR is that the overall

thermal efficiency is greater than that of a
pressurized water reactor because there is no
separate heat exchanger.
➢ The pressure inside the pressure vessel is not high
so, a thicker vessel is not required.

Disadvantages of BWR

➢ Possibility of radioactive contamination in the

turbine mechanism.
 Gas Turbine Power Plant

In steam turbine plants, the products of combustion do not form the

working medium. These are utilized to produce the intermediate fluid,
i.e., the steam which is expanded in the turbine. If this intermediate
step of converting water to steam by means of gases is eliminated, the
arrangement would be far simpler and less wasteful. This principle is
used in gas turbine power plants where the gases are directly
expanded through the several ring of fixed and moving blades.
 Gas turbine power plant Combustor
Nozzle
Hot gas
Fuel

Coupling
Compressor Turbine

Generator

Air inlet Exhaust

Arrangement of simple gas turbine plant

➢ In principle, a gas turbine plant consists of a compressor in which the working

medium is raised to a high pressure. So, generally, a centrifugal or an axial
compressor is employed.
➢ The turbine drives the compressor and so it is coupled to the turbine shaft. From
the compressor, the working medium is taken to a combustor where its
temperature is raised. This high pressure and high temperature working medium is
then expanded in a gas turbine. In the turbine blading, the expansion of the
working gas takes place and the heat energy is converted first into the kinetic
energy and then into the work of the turbine shaft rotation.
 Components of a gas turbine
power plant
1. Gas turbine – There are two basic types of gas turbines
l viz., radial flow and axial flow turbines
a
o 2. Air-compressor – There are mainly two types of air-
compressors used in gas turbine power plants viz.,
h centrifugal compressor and axial flow compressor.

3. Combustion chamber
 Axial flow compressor of
gas turbine power plant

Air in Air out

Rotor
➢

➢
Air in Air out
Casing ➢
Stationary blades
f

An axial flow compressor l

85
 Combustion chamber of gas
turbine power plant
Igniter Air stream around combustion chamber
Primary zone

Diluting or mixing zone

Air from air Hot gases to

compressor turbinenozzles

Tertiaryzone
Fuel oil from pump Outercasing
Acombustion chamberof gasturbine
86
Gas Turbine Power Plant

87
 Closed and open cycle plants
Fuel (heat)

Heater
Combustion Shaft
Compressor chamber Turbine
Work Work
Turbine
Shaft Compressor
Cooling chamber

Air in Exhaust
Open cycle gas turbine

Closed cycle gas turbine

➢ In this turbine, the air from the ➢ In this turbine, the working fluid is
atmosphere is drawn into the compressed.
compressor. ➢ The compressed gas is heated (by
➢ After compression, it is passed into a burning fuel or by nuclear reactor)
combustion chamber.
➢ It is then made to flow over the
➢ The hot gas is then made to flow over turbine blades and gets expanded.
es the turbine blades. The gas, while ➢ From the turbine, the gas is passed
flowing over the blades, gets expanded to the cooling chamber.
and finally exhausted into atmosphere.
losses in the drive. ➢ The air is then made to flow into the
compressor.
s

8
9
Advantages of gas turbine power plant
1. The mechanical efficiency of a gas turbine (95%) is quite higher than the IC
engine (85% ) since the IC engine has many sliding parts.
2. The work developed by a gas turbine per kg of air is more than an IC
engine.
3. Gas turbine power plants are compact in design and can generate high
power. They require less space than steam turbines or IC engines.
4. Compared with steam plants, they have lower initial cost/unit output.
5. Gas turbine power plants have bigger power weight ratio, so it is very
useful for marine power plants.
6. The machine is simple to operate and is smooth running.
7. It requires little or no water for cooling.
8. They have relatively low maintenance costs.
Disadvantages of gas turbine power plant
1. The thermal efficiency of a simple turbine cycle is low (15 to 20%) as
compared with I.C. engines (25 to 30%).
2. Its overall efficiency is very low since a large proportion of the power
developed, about three fourth, is required to drive the compressor and also
by the temperatures safely attainable.
3. The noise of operation is a source of extreme annoyance unless the plant
design includes sound control features.