Growth and Future Trends of Wind Energy in India

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A.I.S.S.M.S’S, C.O.E, Pune.

TECHNICAL PAPER PRESENTATION

A TECHNICAL PAPER

ON

GROWTH AND FUTURE TRENDS OF WIND ENERGY IN

INDIA

BY

TARDE VISHWAJEET VIJAY

TE – MECHANICAL ENGINEERING (SANDWICH)

EXAMINATION NO: - T3211257

UNDER THE GUIDANCE OF

Prof. P. S. AGLAWE

DEPARTMENT OF MECHANICAL ENGINEERING

ALL INDIA SHRI SHIVAJI MEMORIAL SOCIETY’S

COLLEGE OF ENGINEERING

PUNE – 411001

2009-2010

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ALL INDIA SHRI SHIVAJI MEMORIAL SOCIETY’S

COLLEGE OF ENGINEERING, PUNE – 1

DEPARTMENT OF MECHANICAL ENGINEERING

CERTIFICATECERTIFICATECERTIFICATECERTIFICATE

This is to certify that Mr. TARDE VISHWAJEET VIJAY has successfully

carried out the technical paper presentation-I on “Growth and future trends of

wind energy in India” during the academic year 2009-2010 for the partial

fulfillment for the award of degree of Mechanical Engineering (Sandwich) of the

University of Pune.

Examination No: T3211257

Prof. P. S. AGLAWE Prof. S. V.CHAITANYA

Guide Head of Department

External Examiner

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ACKNOWLEDGEMENTACKNOWLEDGEMENTACKNOWLEDGEMENTACKNOWLEDGEMENT

I am very happy to have this opportunity to express my deep and sincere

feelings, words, expression. This seminar would not be possible without the

valuable guidance of my technical paper presentation guide Porf. P. S. Aglawe

who will always have my endless gratitude and admiration, working with him has

been an always be a rewarding and satisfying experience. I wish to express my

esteem regards to Prof. S. V. Chaitanya, Head, Department of Mechanical

engineering for his kind help, co-operation, expert suggestions, moral support and

for providing necessary facilities.

VISHWAJEET V. TARDE

T.E. Mechanical Sandwich

A.I.S.S.M.S. COE, Pune

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ABSTRACTABSTRACTABSTRACTABSTRACT

This seminar entitled as “Growth and future trends of wind energy in

India” takes a look at the wind energy, growth of wind energy and future trends of

wind energy in India that is largely influential in reducing the power crisis in

current time.

Wind energy that makes the use of wind tubines and other systems to

develop power. This is basically the energy with the help of which one can

generate electricity and can use it for any application.

The paper takes a look at wind energy right from the historical background,

Turbine design and construction, Calculation of Wind Power, Future trends in size,

Future trends in Rotational control, Superconducting future, Wind turbine safety,

Costs of a Wind Turbine.

Today INDIA is biggest market of wind energy and standing at 4th position

in the world with 41.5% growth rate. Suzlon developed Asia’s largest wind farm at

Gujarat. Government of INDIA has established a centre for Wind Energy

Technology at Chennai with field station to act as technical focal point for wind

power development in the country.

The paper also review the Wind Farms in India, wind energy generating

capacity in INDIA and Prediction of Indian wind energy market at 2020.

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CONTENTSCONTENTSCONTENTSCONTENTS

1. Introduction 1

1.1 The History of Wind 2

1.2 Fundamentals of Wind Energy 2

1.3 Coriolis force 3

1.4 Betz Limit 4

2. TYPES OF WIND MACHINES 4

2.1 Horizontal-axis 4

2.2 Vertical-axis 5

3. Main Components of Wind Turbine 7

4. Turbine design and construction 13

4.1 Blades 13

4.2 Blade design 13

4.3 Tower height 14

4.4 Number of blades 14

5. Calculation of Wind Power 16

6. Future trends 17

6.1 Trends in size 17

6.2 A superconducting future 18

6.3 Rotational control 18

7. Wind turbine safety 20

7.1 Sensor 20

7.2 Over speed Protection 20

8. Costs of a Wind Turbine 21

9. Growth in Indian Wind Energy Market 22

9.1 Wind Farms in India 23

9.2 Future of wind energy in INDIA 25

10. Advantages 27

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1. Introduction

In continuous search of clean and safe renewable energy sources, wind power is one of

the most attractive solutions. Wind energy is considered to be very clean, cheap and one of

important renewable energy sources.

Wind energy is the manifestation of solar energy. Wind is the air-in-motion. Energy in the

wind is converted into rotary mechanical energy by the use of wind turbine. And this mechanical

energy is used for several purposes such as:-

a) Pumping water

b) Driving generator rotor to produce electrical energy

c) Grinding flour

In reality, wind energy is a converted form of solar energy. The sun’s radiation heats

different part s of the earth at different rates-most notably during the day and night, but also

when different surfaces (for example, water and land) absorb or reflect at different rates. This in

turn causes portions if the atmosphere to warm differently. Hot air rises, reducing the

atmospheric pressure at the earth’s surface and cooler air is drawn in to replace it. The result is

wind.

Air has mass and when it is in motion, it contains the energy of that motion (“Kinetic

energy”). Some portion of that energy can converted into other forms mechanical force or

electricity that we can use to perform work.

So for this conversion purpose we need to build up Wind Energy Conversion System

(WECS). These conversion systems consist of wind turbines which are to be installed in rural

areas, farms, remote areas, on-shore, and off-shore away from the main electrical grids. When

number wind turbines are installed in the above areas or locations they are called as “Wind

Power Plants”.

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1.1 The History of Wind

Since ancient times, people have harnessed the winds energy. Over 5,000 years ago, the ancient

Egyptians used wind to sail ships on the Nile River. Later, people built windmills to grind wheat

and other grains. The earliest known windmills were in Persia (Iran). These early windmills

looked like large paddle wheels. Centuries later, the people of Holland improved the basic design

of the windmill. They gave it propeller-type blades, still made with sails. Holland is famous for

its windmills.

American colonists used windmills to grind wheat and corn, to pump water, and to cut wood at

sawmills. As late as the 1920s, Americans used small windmills to generate electricity in rural

areas without electric service. When power lines began to transport electricity to rural areas in

the 1930s, local windmills were used less and less, though they can still be seen on some

Western ranches.

The oil shortages of the 1970s changed the energy picture for the country and the world. It

created an interest in alternative energy sources, paving the way for the re-entry of the windmill

to generate electricity. In the early 1980s wind energy really took off in California, partly

because of state policies that encouraged renewable energy sources. Support for wind

development has since spread to other states, but California still produces more than twice as

much wind energy as any other state.

1.2 Fundamentals of Wind Energy

• Wind is moving air and is caused by

differences in air pressure within our

atmosphere.

• As the sun strikes the earth, it heats the

soil near the surface. In turn, the soil

warms the air lying above it.

• Warm air is less dense than cool air and,

like a hot-air balloon, rises, cool air flows Figure no.1 Wind Production

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in to take its place and becomes heated.

• The rising warm air eventually cools and falls back to earth, completing the convection

cycle. This cycle is repeated over and over again, rotating like the crankshaft in a car, as

long as the solar engine driving it is in the sky.

• The atmosphere is a huge, solar-fired engine that transfers heat from one part of the globe

to another.

• The large-scale convection currents, set in motion by the sun’s rays, carry heat from

lower latitudes to northern climates.

• The rivers of air that rush across the surface of the earth in response to this global

circulation are called wind. This wind resource is renewable and inexhaustible, as long as

sunlight reaches the earth.

• The direction of the wind is expressed as the direction from which the wind is blowing.

For example, westerly winds blow from east to west, while westerly winds blows from

west to east.

• During the day, the air above the land heats up more quickly than the air over water.

• The warm air over the land expands and rises, and the heavier, cooler air rushes in to take

its place, creating winds.

• At night, the winds are reversed because the air cools more rapidly over land than over

water. This wind flow is called as local wind.

1.3 Coriolis force

• Wind doesn’t follow a straight path from high pressure

systems to low pressure systems. When you stand

with your back to the wind direction, wind is

deflected to the right on the Northern Hemisphere,

and to the left on the Southern Hemisphere. This

phenomenon is caused by the rotation of the earth

and is called the coriolis force, after the Frenchman

Gustave-Gaspard de Coriolis (1792-1843) who

discovered in 1835. Figure no.2 Coriolis force

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1.4 Betz Limit

All wind power cannot be captured by rotor

or air would be completely still behind rotor

and not allow more wind to pass through.

Theoretical limit of rotor efficiency is 59%

Most modern wind turbines are in the 35 –

45% range

Figure no.3 Betz Limit

2. TYPES OF WIND MACHINES

There are two types of wind machines (turbines) used today based on the direction of the rotating

shaft (axis): horizontal–axis wind machines and vertical-axis wind machines. The size of wind

machines varies widely. Small turbines used to power a single home or business may have a

capacity of less than 100 kilowatts. Some large commercial sized turbines may have a capacity

of 5 million watts, or 5 megawatts. Larger turbines are often grouped together into wind farms

that provide power to the electrical grid.

2.1 Horizontal-axis

Most wind machines being used today are the horizontal-axis type. Horizontal-axis wind

machines have blades like airplane propellers. A typical horizontal wind machine stands as tall

as a 20-story building and has three blades that span 200 feet across. The largest wind machines

in the world have blades longer than a football field! Wind machines stand tall and wide to

capture more wind.

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Utility-Scale HAWT’s

� Rotor Diameter:

– 40-95 m Onshore

– 90-114 m Offshore

� Tower: 25-180 meters

� Capacity:

– 0.1-3 MW Onshore

– 3-6 MW Offshore

� Start up wind speed: 4-5 mps

� Max operating wind speed ~16 mps Figure no.4 Horizontal axis turbine

� Low speed shaft: 30-60 RPM

� High speed shaft: 1000-1800 RPM

2.2 Vertical-axis

Vertical–axis wind machines have blades that go from top to

bottom and the most common type (Darrieus wind turbine)

looks like a giant two-bladed egg beaters. The type of

vertical wind machine typically stands 100 feet tall and 50

feet wide. Vertical-axis wind machines make up only a very

small percent of the wind machines used today.

Figure no.5 Vertical axis turbine

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The Wind Amplified Rotor Platform (WARP) is a different kind of wind system that is designed

to be more efficient and use less land than wind machines in use today. The WARP does not use

large blades; instead, it looks like a stack of wheel rims. Each module has a pair of small, high

capacity turbines mounted to both of its concave wind amplifier module channel surfaces. The

concave surfaces channel wind toward the turbines, amplifying wind speeds by 50 percent or

more. Eneco, the company that designed WARP, plans to market the technology to power

offshore oil platforms and wireless telecommunications systems.

Figure no.6 Mag Wind

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3. Main Components of Wind Turbine

Figure no.7 Main components of wind turbine

The wind turbine

• Wind turbines or wind generators are machines that capture the kinetic energy in the

wind and convert to mechanical or electrical energy that can then be applied to some use.

When hot or cool breezes, a wind turbine produces electricity.

• The wind blows through blades, which converts the wind’s energy into rotational shaft

energy.

• The blades are mounted atop a high tower to a drive train, usually with a gearbox, that

uses the rotational energy from the blades to spin magnets in the generator and convert

that energy into electrical currents.

• The shaft, drive train and generator are covered by a protective enclosure called a nacelle.

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• Electronic and electrical equipment including controls, electrical cables, ground support

equipment, and interconnection equipment control the turbine, ensure maximum

productivity and transmit the electrical current. Today’s utility-scale turbines can be 100

meters high or more.

Although machines vary, most wind turbines begin spinning at wind speeds of about 3-4 m/s

and begin generating ele4ctricity at 9-11 mph (4-5 m/s). They produce increasing power with

increasing wind speeds until wind speeds reach about 11-14 m/s, at which speed most wind

turbines reach their “rated” output. Most wind turbines do not operate in wind speeds above

25-30 m/s.

Modern wind energy systems operate automatically. The wind turbines depend on the same

aerodynamic forces created by the wings of an aero plane to cause rotation. An anemometer

that continuously measures wind s[peed is part of most wind turbines control systems. When

the wind speed is high enough to overcome friction in the wind turbine drive tr5ain, the

controls allow the rotor to rotate, thus producing a very small amount of power. This cut-in

wind speed is usually a gentle breeze of about 4 m/s. Power output increases rapidly as the

wind speed rises. When output reaches the maximum power the machinery was designed for,

the wind turbine controls govern the output to the rated power. The wind speed at which

rated power is reached is called the rated wind speed of the turbine, and is usually a strong

wind of about 15 m/s. eventually, if the wind speed increases further, the control system

shuts the wind turbine down to prevent damage to the machinery. This cut-out wind speed is

usually around 25 m/s.

The major components of modern wind energy systems typically consist of the following:

• Rotor, with 2 or 3 blades, which converts the energy in the wind into mechanical

energy onto the rotor shaft;

• Gearbox to match the slowly turning rotor shaft to the electric generator;

• Wind turbine generator

• Tall tower which supports the rotor high above the ground to capture the higher wind

speeds;

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• Solid foundation to prevent the wind turbine from blowing over in high winds and/ or

icing conditions;

• Control system to start and stop the wind turbine and to monitor proper operation of

the machinery.

Rotor

The portion of the wind turbine that collects energy from the wind is called the rotor. The rotor

usually consists of two or more wooden, fiberglass or metal blades which rotate about an axis

(horizontal or vertical) at a rate determined by the wind speed and the shape of the blades. The

blades are attached to the hub, which in turn is attached to the main shaft.

Rotor blade of wind turbines operate on either the principle of drag or lift. For the drag design

the wind literally pushes the blades out of the way. Drag powered wind turbines are

characterized by slower rotational speeds and high torque capabilities. They are useful for

pumping, sawing, or grinding work that Dutch, farm and similar “work –horse” wind mills

perform. For example, a farm type wind mill must develop high torque at startup in order to

pump or lift water from the deep well. The lift blade design employs the same principle that

enables airplanes, kites and birds to fly. The blade is essentially an airfoil, or wing. When air

flows past the blade, a wind speed and pressure differential is created in the upper and lower

blade surfaces. The pressure at lower surface is greater and thus acts to lift the blade. When the

blades are attached to a central axis like wind turbine rotor, the lift is translated in to rotational

motion. Lift powered wind turbines have much higher rotational speeds that drag types and

therefore well suited for electricity generation. The concept of lift can be understood by

following examples:-

If you cut the wing of the glider in half you can see that the upper side is curved whereas the

lower side is almost straight. When the wing whistles through the air the air moves faster across

the curved surface. This creates the low pressure pulling the glider wing up.

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Nacelle

The nacelle contains the dey components of the wind turbine, including the gearbox and the

electrical generator. The bedplate is generally made of steel, in modern wind turbines, service

personnel may enter the nacelle form the tower of the turbine.

Main Shaft

The rotor is bolted to a very strong disc on the main shaft of the wind turbine. It is important that

the rotor is firmly secured by a lot of bolts. The gearbox is placed at the other end of the main

shaft.

Gearbox

The gearbox is required up the slow rotational speed of

the low speed shaft before connection to the generator.

The speed of the blade is limited by efficiency and also

by limitations in the mechanical properties of the

turbine and supporting structure. The gearbox ratio

depends on the number of poles and the type of

generator. A fixed speed generator generally has a

gearbox ratio of 75:1 to give accurate frequency.

Figure no.8 Gear box

Towers

The tower on which a wind turbine is mounted is not just a support structure. It also raises the

wind turbine so that its blades safely clear the ground and so it can reach the stronger winds at

higher elevations. Maximum tower height is optional in most cases, except where zoning

restrictions apply. The decision of what height tower to use will be based on the cost of taller

towers versus the value of the increase in energy production resulting from their use. Studies

have shown that the added cost of increasing tower height is often justified by the added power

generated from the stronger winds. Larger wind turbines are usually mounted on towers ranging

from 40 to 70 meters tall.

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Generator

The generator is the unit of the wind turbine that transforms mechanical energy into electrical

energy. The blades transfer the kinetic energy from the wind into rotational energy in the

transmission system, and the generator is the next step in the supply of energy from the wind

turbine to the electrical grid. A detailed description of wind turbine generators is given in

chapter—

Braking mechanism

The power in the wind is proportional to the cube of the wind speed. Considerable forces must

therefore be controlled during high winds in order to attain safe operation. There are usually at

least 2 independent braking systems, each capable of bringing the wind turbine to a safe

condition in cases of high winds, loss of connection to the network or other emergencies. They

are known as aerodynamic braking system and mechanical braking system.

Yaw mechanism

It is necessary to align the rotor axis the wind in order to extract as much energy from the wind

as possible. Most horizontal axis wind turbine use forced yawing. An electrical or hydraulic

system is used to align the machine with the wind. The yaw drive reacts on signals from, e.g. a

wind vane on top of the nacelle. Almost all manufactures of upwind machines brake the yaw

mechanism whenever it is not used. The yaw motor has a small wheel that engages a huge wheel.

The large wheel is called the yaw bearing. On some yaw bearings the teeth point outward. While

on others they are turned inwards. It all depends on the position of the yaw motor.

Pitch mechanism

The rotor blades are connected to the hub via pitch ball bearings and can swivel fully

perpendicular to the sense of rotation. The motors of the pitching system have an inbuilt

intelligent system, with frequency control drives controlled by their own microprocessor. These

intelligent frequency drives talk with the control system in real time. The control system updates

the motors after gauging the available wind regime, and the motors constantly update the control

system on the instant blade angle. The precision electromechanical micro pitch mechanism

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achieves 0.1 deg pitching resolution, resulting in extreme fone-tuning of the aerodynamic profile.

The major components of the pitching systems are shown in following table.

Anemometer

The Anemometer measures the wind speed and notifies the wind turbine controller when it is so

windy that it would be profitable to use power to make wind turbine turn (Yaw) into the wind

and start running. It is important to know how much wind there is. If the wind is too strong the

wind turbine can break. This is why the wind turbine is brought to a stop when the wind exceeds

25 meters per second. When the wind drops, the anemometer tells the controller that it is OK to

start the turbine again.

Wind Vane

A wind vane always positions itself according wind direction. There is a small sensor at the foot

of the wind vane that notifies the wind turbine controller of the wind direction. The controller

tells the yaw motor to yaw (turn) the nacelle so that the rotor faces the wind.

Aerodynamics

The aerodynamics of a horizontal-axis wind turbine is not straightforward. The air flow at the

blades is not the same as the airflow far away from the turbine. The very nature of the way in

which energy is extracted from the air also causes air to be deflected by the turbine. In addition

the aerodynamics of a wind turbine at the rotor surface exhibit phenomena that are rarely seen in

other aerodynamic fields.

Drag and Lift Force

There are two primary physical principles by which energy can be extracted from the wind; these

are through the creation of either drag or lift force (or through a combination of the two).

The basic features that characterize lift and drag are:-

• Drag is in the direction of airflow

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• Lift is perpendicular to the direction of airflow

• Generation of lift always causes a certain amount of drag to be developed

• With a good aerofoil, the lift produced can be more than thirty times greater than the drag

• Lift devices are generally more efficient than drag devices

4. Turbine design and construction

4.1 Blades

Material used

Typical length

• One of the best construction materials available in 2001 is graphite-fibre in epoxy.

Graphite composites can be used to build turbines of sixty meters radius, enough to tap a

few megawatts of power. Smaller household turbines can be made of lightweight

fiberglass, aluminum, or sometimes laminated wood.

• Wood and canvas sails were originally used on early windmills. Unfortunately they

require much maintenance over their service life. Also, they have a relatively high drag

(low aerodynamic efficiency) for the force they capture. For these reasons they were

superseded with solid airfoils.

• Wind power intercepted by the turbine is proportional to the square of its blade-length.

The maximum blade-length of a turbine is limited by both the strength and stiffness of its

material.

4.2 Blade design

• The tip speed ratio is defined as the ratio of the speed of the extremities of a windmill

rotor to the speed of the free wind. It is a measure of the 'gearing ratio' of the rotor. Drag

devices always have tip speed ratios less than one and hence turn slowly, whereas lift

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devices can have high tip speed ratios and hence turn quickly relative to the wind. High

efficiency 3-blade-turbines have tip speed/wind speed ratios of 6 to 7.

• Tip speed ratio = blade tip speed / wind speed

• Solidity is usually defined as the percentage of the circumference of the rotor which

contains material rather than air. High solidity machines carry a lot of material and have

coarse blade angles. They generate much higher starting torque than low-solidity

machines but are inherently less efficient than low-solidity machines. The extra materials

also cost more money. However, low-solidity machines need to be made with more

precision which leads to little difference in costs.

• The proportion of the power in the wind that the rotor can extract is termed the

coefficient of performance (or power coefficient or efficiency; symbol Cp) and its

variation as a function of tip speed ratio is commonly used to characterize different types

of rotor. It is physically impossible to extract all the energy from the wind, without

bringing the air behind the rotor to a standstill.

4.3 Tower height

Heights twice the blade length are found economical

• For HAWTs, tower heights approximately twice the blade length have been found to

balance material costs of the tower against better utilization of the more expensive active

components.

4.4 Number of blades

� Three blade HAWT are most efficient

� Two blade turbines don’t require a hub

� As the number increases; noise, wear and cost increase and efficiency decreases

� Multiple blade turbines are generally used for water pumping purposes

• Although turbines can be built with any number of blades, there are many constraints.

There are a number of vibration modes that increase in peak intensity as the number of

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blades decreases. Some of these vibrations, besides causing wear on the machine, are also

audible. Thus, noise and wear considerations point to larger numbers of blades, generally

at least 3.

• Many small scale wind turbines, such as the Whisper 175, use 2 blades because such

turbines are easy to construct as they avoid the need for using a hub with linkages to

individual blades, and the blade(s) can be shipped easily in one long package. Three-

bladed turbines, which are much more efficient, and quieter, require more complicated

onsite assembly.

Figure no.10 Design of wind turbine blade

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5. Calculation of Wind Power

Power in the Wind = ½ρAV3

Effect of air density, ρ

Effect of swept area, A

Effect of wind speed, V

Swept Area: A = πR2 Area of the circle swept by the

rotor (m2).

Let’s look at wind speed, V. Because V is cubed in the equation, a

small increase in V makes for a increase in power.

Importance of Wind Speed

• No other factor is more important to the amount of power

available in the wind than the speed of the wind

Power is a cubic function of wind speed = V X V X V

• 20% increase in wind speed means 73% more power

• Doubling wind speed means 8 times more power

A “perfect turbine” would work right at Betz Limit, the blades and the alternator would match

perfectly at all wind speeds; alternator would have no integral magnetic or electrical losses .This

is known as coefficient of power Cp

Power co-efficient Cp, describes that fraction of power in the wind that may converted by the

wind turbine in to mechanical work

The actual power output of a wind turbine is given by

P=0.5*ρρρρ*A*Cp*V3*ῃg*ῃb

Figure no.11 Wind power

calculation

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Where, P=Power in watts (746 watts=1hp) (1000watts=1kilowatt)

A= swept area

V= wind speed

Cp= Power co-efficient

ῃg=Generator efficiency

ῃb= Gearbox/bearing efficiency

6. Future trends

6.1 Trends in size

• Further growth in size of offshore turbines but at slower rate.

• Onshore market dominated by turbines of 2 – 3MW rating, up to ~100m diameter.

• Expansion of onshore market for smaller turbines, a few hundred kW rating.

• A typical 600 kW wind turbine has a rotor diameter of 43-44 meters, i.e. a rotor area of

some 1,500 square meters.

• The rotor area determines how much energy a wind turbine is able to harvest from the

wind.

• Since the rotor area increases with the square of the rotor diameter, a turbine which is

twice as large will receive 22 = 2 x 2 = four times as much energy.

Figure no.12 Trends in size

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6.2 A superconducting future

High Temperature Superconducting (HTS) wire to conduct current with negligible losses at

temperature of around 200o C.

6.3 Rotational control

The speed at which wind turbines rotate must be controlled for several reasons:

6.3.a) Maintenance:-because it is dangerous to have people working on a wind turbine while it

is active, it is sometimes necessary to bring a turbine to a full stop.

6.3.b) Noise reduction:- As a rule of thumb, the noise from a wind turbine increases with the

fifth power of the relative wind speed (as seen from the moving tip of the blades). In noise-

sensitive environments (nearly all onshore installations), noise limits the tip speed to

approximately 60 m/s. High efficiency turbines may have tip speed ratios of 5-6, which, for

onshore turbines, limits high efficiency operation to winds of just 10 m/s.

� Streamlining of tower and nacelle

� Acoustic insulation of nacelle

� Specially designed gear box

� Use of upwind turbines

� Reducing angle of attack

� Low tip speed ratios

• Most rotors are upwind: A wind turbine can

be either "upwind" (that is, where the rotor

faces into the wind) or "downwind" (where

the rotor faces away from the wind). A

downwind design offers some engineering

advantages, but when a rotor blade passes the Figure no.13 Noise level

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"wind shadow" of the tower as the rotor revolves, it tends to produce an "impulsive" or

thumping sound that can be annoying. Today, almost all of the commercial wind

machines on the market are upwind designs, and the few that are downwind have

incorporated design features aimed at reducing impulsive noise (for example, positioning

the rotor so that it is further away from the tower).

• Towers and nacelles are streamlined: Streamlining (rounding or giving an aerodynamic

shape to any protruding features and to the nacelle itself) reduces any noise that is created

by the wind passing the turbine. Turbines also incorporate design features to reduce

vibration and any associated noise.

• Soundproofing in nacelles has been increased: The generator, gears, and other moving

parts located in the turbine nacelle produce mechanical noise. Soundproofing and

mounting equipment on sound-dampening buffer pads helps to deal with this issue.

• Gearboxes are specially-designed for quiet operation: Wind turbines use special

gearboxes, in which the gear wheels are designed to flex slightly and reduce mechanical

noise. In addition, special sound-dampening buffer pads separate the gearboxes from the

nacelle frame to minimize the possibility that any vibrations could become sound.

6.3.c) Centripetal force reduction: - as the rotational speed increases, so does the centripetal

force working on the central hub or axis. When it exceeds safe limits blades could snap off, and

the turbine would fail dramatically.

• On a pitch controlled wind turbine the turbine's electronic controller checks the power

output of the turbine several times per second. When the power output becomes too high,

it sends an order to the blade pitch mechanism which immediately pitches (turns) the

rotor blades slightly out of the wind. Conversely, the blades are turned back into the wind

whenever the wind drops again.

• (Passive) stall controlled wind turbines have the rotor blades bolted onto the hub at a

fixed angle.

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• The geometry of the rotor blade profile, however has been aerodynamically designed to

ensure that the moment the wind speed becomes too high, it creates turbulence on the

side of the rotor blade which is not facing the wind. This stall prevents the lifting force of

the rotor blade from acting on the rotor.

7. Wind turbine safety

That part of the rotor which is closest to the source direction of the wind, however, will be

subject to a larger force (bending torque) than the rest of the rotor. On the one hand, this

means that the rotor will have a tendency to yaw against the wind automatically, regardless

of whether we are dealing with an upwind or a downwind turbine. On the other hand, it

means that the blades will be bending back and forth in a flap wise direction for each turn of

the rotor. Wind turbines which are running with a yaw error are therefore subject to larger

fatigue loads than wind turbines which are yawed in a perpendicular direction against the

wind.

7.1 Sensor

It simply consists of a ball resting on a ring. The ball is connected to a switch through a

chain. If the turbine starts shaking, the ball will fall off the ring and switch the turbine off.

There are many other sensors in the nacelle, e.g. electronic thermometers which check the oil

temperature in the gearbox and the temperature of the generator.

7.2Over speed Protection

It is essential that wind turbines stop automatically in case of malfunction of a critical

component

a) Aerodynamic Braking System: Tip Brakes

The primary braking system for most modern wind turbines is the aerodynamic braking

system, which essentially consists in turning the rotor blades about 90 degrees along their

longitudinal axis (in the case of a pitch controlled turbine or an active stall controlled turbine

), or in turning the rotor blade tips 90 degrees (in the case of a stall controlled turbine ).

Aerodynamic braking systems are extremely safe.

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b) Mechanical Braking System

The mechanical brake is used as a backup system for the aerodynamic braking system.

8. Costs of a Wind Turbine

� A typical 600 kW turbine costs about $450,000.

� Installation costs are typically $125,000.

� Therefore, the total costs will be about $575,000.

� The average price for large, modern wind farms is around $1,000 per kilowatt electrical

power installed.

� Modern wind turbines are designed to work for some 120,000 hours of operation

throughout their design lifetime of 20 years. ( 13.7 years non-stop)

� Maintenance costs are about 1.5-2.0 percent of the original cost, per year.

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9. Growth in Indian Wind Energy Market

The Indian wind energy sector has an

installed capacity of 10,464.00 MW (as

on July 31, 2009). In terms of wind power

installed capacity, India is ranked 4th in

the World. Today India is a major player

in the global wind energy market.

The potential is far from exhausted.

Indian Wind Energy Association has

estimated that with the current level of

technology, the ‘on-shore’ potential for

utilization of wind energy for electricity

generation is of the order of 65,000 MW.

The unexploited resource availability has

the potential to sustain the growth of wind

energy sector in India in the years to

come.

India ranks fourth amongst the wind-energy-producing countries of the world after

Germany, Spain and USA.

• India's position was 3rd in the World till September 96, thereafter it became 4th up to

December 98, 5th up to December 04 and now it is 4th again.

• Estimated potential is around 45000 MW at 50 m above ground level.

• Exhaustive wind resource assessment has been carried out in 598 stations spread over 27

States in the country. As on date 225 Wind Monitoring stations have indicated wind

power density more than 200 W/m2 at 50 m above ground level.

2009 Capacity and Growth Rate of Top Six

Countries

Ranking

2009

Country Growth

Rate (%)

Capacity

(MW)

1 Germany 11.9 20,622

2 Spain 15.8 11,615

3 USA 26.8 11,603

4 India 41.5 10,464

5 Denmark 2.4 8,136

6 China 90.9 7,405

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• Micro Survey of Wind Resource for 97 Wind Monitoring Stations have been completed

to know the zone of influence and Wind Power Potential around the stations to meet the

requirement of wind energy developers in the country.

• Wind farms have been installed in more than 9 States.

• More than 95% of installed capacity belongs to Private Sector in seven states

• A good number of wind turbine manufacturers are active in India and producing Wind

Electric Generators (WEGs) of rating 225 kW to 2100 kW.

• A large number of agencies have come up to supply components/spares/ accessories and

to provide services like Erection, O&M, Civil & Electrical Construction, Consultancy

etc.

• A large number of water pumping windmills and small aero-generators have been

installed in the country.

• Wind-Solar and Wind-Diesel Hybrid systems have also been installed at a few places.

• The Central Ministry and several State Nodal Agencies encourage growth of Wind

Energy Sector through financial incentives and policy support.

• The Ministry of New & Renewable Energy (MNRE), Govt. of India has established a

Centre for Wind Energy Technology at Chennai with field test station at Kayathar to act

as technical focal point for wind power development in the country.

• Financial assistance for Renewable source of energy is available through Indian

Renewable Energy Development Agency, a supporting arm of MNRE, GOI.

9.1 Wind Farms in India

Suzlon has developed more than 50 wind farm projects spread across 8 states of India.

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Further development is underway to expand

existing wind power projects and add new

ones. Suzlon takes pride in the development of

three of Asia’s largest wind farms. Apart from

this, Suzlon has also been active on many CSR

initiatives in partnership with several NGOs.

The Kutch Wind Farm, Gujarat

Asia’s largest wind farm developed and operated

by Suzlon, it has more than 750MWof wind

power capacity already installed, and further

capacity addition is in progress. This wind farm

comprises of Suzlon’s time tested wind turbines

of 600kW, 1250kW, and 1500kW

capacity. Figure no.14 INDIAN Wind market

The Dhule Wind Farm, Maharashtra

The Dhule wind farm is Asia’s second largest wind

farm with an installed capacity in excess of 675 MW.

This wind farm comprises of Suzlon’s time tested

wind turbines of 600kW, 1250kW and 1500kW

capacity.

The Sankaneri Wind Farm, Tamil Nadu

India’s southern peninsular region in Tamil Nadu is

blessed with one of the best wind power potential.

Thanks to its unique topography that exposes it to two

monsoon seasons in a year, the windy season extends

Graph no.1 Growth in Suzlon’s cumulative

installed base in India

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over a longer period. Suzlon’s Sankaneri wind farm hosts more than 650MW of installed

capacity. This wind farm comprises of Suzlon’s time tested wind turbines of 350kW, 600kW,

1250kW, and 1500Kw

State & Total

Cumulative Installed

Base (MW)*

Key wind farms in the state

Andra Pradesh - 8.5MW Tirupati

Gujarat - 876MW Kutch, Bhogat, Sanodar

Kerala - 14MW Agali

Karnataka - 490MW Kapathgudda, Hassan, Jaijikalgudda

Maharashtra - 1350MW Dhule, Sangli, Satara, Supa, Gudhe

Panchgani

Madhya Pradesh - 53MW Ratlam, Devas

Rajasthan - 423MW Soda-Moda, Ratan ka Bas

Tamil Nadu - 1275MW Sankaneri, Palladam, Devarkulam

*As of 31 March 2009

9.3 FUTURE OF WIND ENERGY IN INDIA

Worldwide wind generating capacity is less than 5000 MW in 1995 and is 39000MW in 2003, an

increase of nearly eight fold. Wind energy is the fastest growing renewable energy source in the

world. The worldwide installed capacity is growing at a rapid pace of over 30% per year.

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Graph no.2 Wind Energy generating capacity by country, 1980-

2003

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Graph no.3 Prediction of Indian wind energy market at 2020

10. Advantages

No delay in construction: wind turbines are easy to construct and does not require long gestation

periods.

Low maintenance costs: maintenance costs are very small compared to installation costs.

Reliable and durable equipment: except for wind speeds greater than 30 mi/hr, once installed,

wind equipment last for more than 25 years.

Farmers and ranchers earn additional income by leasing their land for wind turbine.

Wind industry produces more jobs per unit energy produced than other forms of energy.

No hidden costs, which greatly reduces the environmental impacts

Greater fuel diversity.

Wind energy is big business turning over A$13 billion globally and employing 100,000

people in 2003. By 2020, the industry is expected to employ 1.8 million people and be

worth $A120 billion a year.

Due to these advantages of wind energy the future of wind energy market is bright.

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CONCLUSCONCLUSCONCLUSCONCLUSIONIONIONION

As we know that wind energy is a non-conventional source of energy it should be utilized as

much as possible. Because of its ability to supply electricity continuous as per requirement

this becomes useful particularly where the power generated by conventional sources is

difficult to reach due to high cost and where power failure is frequent.

The trend in size, superconducting, rotational control increases the efficiency of wind

turbine. Today wind turbines are safer due to use of sensor, over speed protection, limit

switch. The conversion of energy from wind to electrical is pollution free. The wind energy

conversion systems are also cheaper for installation.

So maximum use of this energy will keep the problem of the power generation away.

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REFERENCESREFERENCESREFERENCESREFERENCES

1. ESSENTIALS OF WIND POWER GENERATION Participant Workbook by

SUZLON (Corporate Learning Centre)

2. INDIA A SNAPSHOT BOOK by SUZLON (powering a greener tomorrow, today.)

3. www.suzlon.com (Wind Energy in India : Realisable Option for Power

Generation by Harish Mehta Director SUZLON Group of Companies)

4. www.osun.org (SHORT PRESENTATION BY IWTMA CHENNAI 25.11.08 )

5. TRENDS IN WIND TURBINE TECHNOLOGY by Philip Wong Too, Peter

Jamieson, Ollie Manins, William Thorp Garrad Hassan April 2009

6. AERODYNAMICS 2: BLADE DESIGN References: NREL (Pat Moriarty, Tony

Jimenez)

7. Entrepreneurship Awareness Camp 4th

-6th

September 2008 Organized by VITTBI

presentation by K.S.Krithivasan, BHEL,Ranipet

Growth and Future Trends of Wind Energy in India

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