WIND ENERGY: GREEN, FREE & EFFICIENT

WIND ENERGY
Green, Free & Efficient
SUPERVISED BY:
Dr. Mohammad Ilias Inam
Assistant Professor,
Department of Mechanical Engineering,
Khulna University of Engineering & Technology,
Khulna-9203.
PREPARED BY:
Md. Faysal Hossain
Roll no. 1405079
Section: B
Department of Mechanical Engineering.
Khulna University of Engineering & Technology.
Khulna-9203.

ACKNOWLEDGEMENT
Firstly, I want to express gratefulness to Almighty ALLAH for His immense blessing upon me
for the successfulness completion of this work.
I would like to express my sincere gratitude to my supervisor, Dr. Mohammad Ilias Inam,
Associate Professor, Department of Mechanical Engineering, KUET for his valuable
suggestions, guidance and constant encouragement during pursuit of this work. His profound
knowledge, excellent understanding, crystal clear concepts benefited me very much. I am very
grateful to him.
I am extremely grateful to Prof. Md. Golam Kader, Head of the Department of Mechanical
Engineering, KUET to provide such a good opportunity to do such a study and providing all
other supports.
Finally, I would like to express my gratitude for my family who have given support to my study
and prayed for my life.
Md. Faysal Hossain

ABSTRACT
From the early ages to present wind is used for many purposes but the field is different. In
modern ages wind energy is mostly used for electricity generation by wind turbines. Winds flows
from one end of the earth to another end because of pressure gradients. These kinetic energy of
wind is used in different purposes, in the context of wind turbine to rotate the turbines.
There are different types of wind turbines, where some are onshore and some are offshore. On
the other hand some are vertical axis turbine and some are horizontal axis turbine. They are used
in different places in different situations. Now a day’s the wind power chalks up more strong
numbers.
As energy demand in Bangladesh is very high, wind energy, the potential energy source, may be
an effective source of energy for this country.

CONTENTS
Acknowledgement
Abstract
1.0 Introduction
2.0 Objectives
3.0 Historical Background
4.0 Causes Behind The Flow of Wind
5.0 Advantages and Challenges of Wind Energy
6.0 Power in Wind
7.0 Different Types of Wind Turbines
8.0 The Inside of a Wind turbine
9.0 Onshore and Offshore Wind Turbines
10.0 Stabilization of an Offshore Floating Wind Turbine
11.0 Global Status of Wind Power
12.0 Wind Energy Potential in Bangladesh
13.0 Conclusion
Reference

1. INTRODUCTIN:
People are always concern to the mines or other assets they can see. Countries are fighting,
conspiring and quarreling against other countries to gain the control over the mines which are the
source of modern energy. But the source of energy which is free and available to all, the wind
energy, are overlooked for many years.
But In recent years, wind energy has become one of the most economical renewable energy
technology. Today, electricity generating wind turbines employ proven and tested technology,
and provide a secure and sustainable energy supply. At good, windy sites, wind energy can
already successfully compete with conventional energy production [1]. Many countries have
considerable wind resources, which are still untapped.
The technological development of recent years, bringing more efficient and more reliable wind
turbines, is making wind power
more cost-effective. In general,
the specific energy costs per
annual kWh decrease with the
size of the turbine
notwithstanding existing supply
difficulties.
Many African countries expect
to see electricity demand expand
rapidly in coming decades. At
the same time, finite natural
resources are becoming
depleted, and the environmental
impact of energy use and energy
conversion have been generally
accepted as a threat to our Fig. 1.1: Wind Turbine
natural habitat. Indeed these have become major issues for international policy [2].
Many developing countries and emerging economies have substantial unexploited wind energy
potential. In many locations, generating electricity from wind energy offers a cost-effective
alternative to thermal power stations. It has a lower impact on the environment and climate,
reduces dependence on fossil fuel imports and increases security of energy supply [3].
For many years now, developing countries and emerging economies have been faced with the
challenge of meeting additional energy needs for their social and economic development with
obsolete energy supply structures. Overcoming supply bottlenecks through the use of fossil fuels
in the form of coal, oil and gas increases dependency on volatile markets and eats into valuable
foreign currency reserves. At the same time there is growing pressure on emerging newly

industrialized countries in particular to make a contribution to combating climate change and
limit their pollutant emissions.
In the scenario of alternatives, more and more developing countries and emerging economies are
placing their faith in greater use of renewable energy and are formulating specific expansion
targets for a ‘green energy mix’. Wind power, after having been tested for years in industrialized
countries and achieving market maturity, has a prominent role to play here. In many locations
excellent wind conditions promise inexpensive power generation when compared with costly
imported energy sources such as diesel. Despite political will and considerable potential,
however, market development in these countries has been relatively slow to take off. There is a
shortage of qualified personnel to establish the foundations for the exploitation of wind energy
and to develop projects on their own initiative. The absence of reliable data on wind potential
combined with unattractive energy policy framework conditions deters experienced international
investors, who instead focus their attention on the expanding markets in Western countries.
It is only in recent years that appreciable development of the market potential in developing
countries and emerging economies has taken place. The share of global wind generating capacity
accounted for by Africa, Asia and Latin America reached about 20% at the end of 2008, with an
installed capacity of 26 GW. This is attributable above all to breathtaking growth in India and
China: these two countries alone are responsible for 22 GW. This proves that economic use of
wind energy in developing countries and emerging economies is possible, and also indicates that
there is immense potential that is still unexploited [4].

2. OBJECTIVES:
The basic objective of this report is to
a) Studying on the Wind energy and Wind turbine.
b) Identifying in which condition what kind of turbine is more effective.
c) Studying on the challenges of building up a wind turbine.
d) Studying the wind energy potential in Bangladesh.

3. HISTORICAL BACKGROUND:
Fig 3.1: Windmills used to pumping water
In the early ages, the first recording of a windmill came from a Hindu book dating back to about
400 B.C.E. Scientists believe that the first windmills created to do work were created in China
2000 years ago. There is no written history of this however. The first recorded windmills that
were created to do work are from seventh-century Persia. The first historical reference to
Chinese windmills was in 1219. This is significant because during this time windmills were used
along the coast of china for wind power [5]. Some windmills are still intact in Iran and
Afghanistan from the 7th century [6].
These windmills are reverse of the windmills today. However, wind energy went into a chamber
to turn blades, while today the blades are on an external axis. They are still around today and can
grind about a ton of grain per day.

Fig. 3.2: Windmills used in agriculture
After technology was brought back from the Crusades Early European windmills
were used to drain wet land by pumping water. The design of the European windmills was based
on the water wheel due to the fact that windmills should be put on a vertical axis when the
windmills in Persia were built on a horizontal axis. During this time the foundation for windmills
was set. It was up for inventors to create new blades and other ways to make the windmill more
efficient.
By the end of the nineteenth century there were over 30,000 windmills in Europe. They were
used for more than just pumping water and grinding grain, people used them to run saw mills and
other industrial plants. Until the late nineteenth century windmills would only produce
mechanical power for their tasks such as grinding grain or pumping water.

With the creation of electricity, windmill makers found that windmills could be attached to a
generator and used to create power for heating and lighting.
The first windmill used to produce electric energy was created in 1888 by Charles F. Brush.
These windmills needed to produce 500 revolution per minute in order to power a generator.
From the 1930’s to the 70’s coal and oil were relatively inexpensive and wind energy lost its
popularity in America though windmills were used in many other countries throughout the world
In 1973 America was affected by the Arab oil embargo. This caused focus to turn toward wind
power. The U.S. Federal Wind Energy Program was established in 1974.
By the late 1980’s it was becoming very difficult to attract funding for wind energy because
people did not believe that wind power could be strong enough to produce the same amount of
power as oil.
Modern wind power is a strong option for alternative energy, and its rich history proves it can be
used effectively.
Fig. 3.3: Modern ages Wind Turbines

4.0 CAUSES BEHIND THE FLOW OF WIND:
To understand what makes the wind blow, we first need to understand what atmospheric pressure
is.
Pressure=force/area; in the case of air pressure, force is the weight of air.
Pressure at the earth's surface is a measure of the 'weight' of air pressing down on it. The greater
the mass of air above us, the higher the pressure we feel, and vice-versa.
From Bernoulli’s equation we can see, 𝑝 +
1
2
𝑉2
𝜌 + 𝛾𝑍 = 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡
If the elevation Z is constant then ∆𝑝 = −
𝜌
2
∆𝑉2
where the (-) ve sign represents the velocity
change is in the opposite direction of pressure change. From which we can conclude that the
fluid flows from the high pressure region to the high pressure region.
The importance of this is that air at the surface will want to move from High pressure to low
pressure to equalize the difference, which is what we know as wind.
So wind is caused by differences in atmospheric pressure - but why do we get these differences?
It's down to the rising and sinking of air in the atmosphere. Where air is rising we see lower
pressure at the earth's surface, and where it's sinking we see higher pressure. In fact if it weren't
for this rising and sinking motion in the atmosphere then not only would we have no wind, but
we'd also have no weather.
4.1 Small scale winds:
This rising and sinking of air in the atmosphere takes place both on a global scale and a local
scale. One of the simplest examples of a local wind is the sea breeze. On sunny days during the
summer the sun's rays heat the ground up quickly. By contrast, the sea surface has a greater
capacity to absorb the sun's rays and is more difficult to warm up - this leads to a temperature
contrast between the warm land and the cooler sea [7].

Fig 4.1: Air flow direction during day and night in the coastal region
As the land heats up, it warms the air above it. The warmer air becomes less dense than
surrounding cooler air and begins to rise, like bubbles in a pan of boiling water. The rising air
leads to lower pressure over the land. The air over the sea remains cooler and denser, so pressure
is higher than inland. So we now have a pressure difference set up, and air moves inland from the
sea to try and equalize this difference - this is our sea breeze. It explains why beaches are often
much cooler than inland areas on a hot, sunny day.
4.2 Large scale winds:
A similar process takes place on a global scale. The sun's rays reach the earth's surface in polar
regions at a much more slanted angle than at equatorial regions. This sets up a temperature
difference between the hot equator and cold poles. So the heated air rises at the equator (leading
to low pressure) whilst the cold air sinks above the poles (leading to high pressure). This
pressure difference sets up a global wind circulation as the cold polar air tries to move
southwards to replace the rising tropical air. However, this is complicated by the earth's rotation
(known as the Coriolis Effect).

Fig 4.2: Generalized sketch of global atmospheric circulation
Air that has risen at the equator moves pole wards at higher levels in the atmosphere then cools
and sinks at around 30 degrees latitude north (and south). This leads to high pressure in the
subtropics - the nearest of these features that commonly affects UK weather is known as the
Azores high. This sinking air spreads out at the earth's surface - some of it returns southwards
towards the low pressure at the equator (known as trade winds), completing a circulation known
as the Global circulation patterns.
Another portion of this air moves pole wards and meets the cold air spreading southwards from
the Arctic (or Antarctic). The meeting of this subtropical air and polar air takes place on a
latitude close to that of the UK and is the source of most of our weather systems. As the warm air
is less dense than the polar air it tends to rise over it - this rising motion generates low pressure
systems which bring wind and rain to our shores. This part of the global circulation is known as
the mid-latitude cell, or Global circulation patterns.

Another important factor is that the Coriolis effect from the earth's rotation meaning that air does
not flow directly from high to low pressure - instead it is deflected to the right (in the northern
hemisphere - the opposite is true in the southern hemisphere) [7].
Fig. 4.3: Wind speed around the earth [8].

5. ADVANTAGES AND CHALLENGES OF WIND ENERGY:
Wind energy is a clean, renewable energy source and offers many advantages, which explains
why it's one of the fastest-growing energy sources in the world. Research is aimed at improving
technology, lowering costs, and addressing the challenges to greater use of wind energy. Read on
to learn more about the benefits of wind power and some of the challenges the industry is
working to overcome.
5.1 Advantages of Wind Energy:
 Wind energy is a clean fuel source. Wind energy doesn't pollute the air like power plants
that rely on combustion of fossil fuels, such as coal or natural gas. Wind turbines don't
produce atmospheric emissions that increase health problems like asthma or create acid
rain or greenhouse gases. According to the Wind Vision Report, wind has the potential to
reduce cumulative greenhouse gas emissions by 14%, saving $400 billion in avoided
global damage by 2050.
 Wind power does not use water, unlike conventional electricity sources. Producing
nuclear, coal, or gas-fired power uses water for cooling. Water is becoming a scarce
resource all over the country. Wind power uses zero water in its energy generation.
 Wind is a domestic source of energy. The nation's wind supply is abundant. Over the past
10 years, wind capacity increased an average of 31% per year, reaching a cumulative
capacity of over 75,000 MW in 2016, enough to power over 20 million homes. Wind
power is the largest source of annual new generating capacity, well ahead of the next two
leading sources, solar power and natural gas.
 Wind power is inexhaustible. Wind is actually a form of solar energy. Winds are caused
by the heating of the atmosphere by the sun, the rotation of the Earth, and the Earth's
surface irregularities. For as long as the sun shines and the wind blows, the energy
produced can be harnessed to send power across the grid.
 Wind power is cost-effective. It is one of the lowest-cost renewable energy technologies
available today, with power prices offered by newly built wind farms averaging 2 cents
per kilowatt-hour, depending on the wind resource and the particular project’s financing.
Even without government subsidies, wind power is a low-cost fuel in many areas of the
country.
 Wind turbines can be built on existing farms or ranches. This greatly benefits the
economy in rural areas, where most of the best wind sites are found. Farmers and
ranchers can continue to work the land because the wind turbines use only a fraction of
the acreage. Wind power plant owners make rent payments to the farmer or rancher for
the use of the land, providing landowners with additional income. In 2015, annual land
lease payments in the United States were estimated to total $222 million. This additional
income provides the agricultural community an avenue to diversify revenue and reduce

reliance on uncertain commodity prices. According to the Wind Vision Report, annual
land lease income for rural American landowners could increase to $1 billion by 2050.
 Wind creates jobs. In 2016, the wind energy sector invested more than $8.8 billion of
private capital in the U.S. economy to build projects and employed more than 101,000
workers (approximately 30% women, 11% veterans, and 25% minorities), according to
the 2017 U.S. Energy and Employment Report. More than 8,800 technicians were
employed in 2015 to monitor and maintain wind turbines, and this profession is expected
to grow by 108% in the next decade, making it the country’s fastest-growing occupation
(according to the Bureau of Labor Statistics). According to the Wind Vision Report, wind
has the potential to support more than 600,000 jobs in manufacturing, installation,
maintenance, and supporting services by 2050.
5.2 Challenges of Wind Power:
 Wind power must compete with conventional generation sources on a cost
basis. Depending on how energetic a wind site is, the wind farm might not be cost
competitive in less windy areas of the country. Even though the cost of wind power has
decreased dramatically in the past 10 years, the technology requires a higher initial
investment than fossil-fueled generators.
 Good wind sites are often located in remote locations, far from cities where the electricity
is needed. Transmission lines must be built to bring the electricity from the wind farm to
the city. According to the American Wind Energy Association, approximately 51,000
MW of new wind capacity could be added if near-term transmission projects in advanced
development are completed. The Energy Department released a report which confirms
that adding even limited electricity transmission can significantly reduce the costs of
expanding wind energy to supply 35% of U.S. electricity by 2050.
 Turbines might cause noise and change the view shed. Although wind power plants have
relatively little impact on the environment and communities compared to conventional
power plants, concern exists over the sound sometimes produced by the turbine blades
and visual impacts to the landscape.
 Though wind turbines harm wildlife less than some conventional sources of electricity,
turbine blades could damage local wildlife. Electricity generation that pollutes the air and
water causes wildlife fatalities through acid rain, mercury poisoning, habitat disruption
due to warming temperatures, and more. However, birds have been killed by flying into
spinning turbine blades. Blade strikes have been greatly reduced through technological
development or by properly siting wind plants. Currently, the National Renewable
Energy Laboratory’s National Wind Technology Center (NWTC) is supporting wildlife
technology research validation designed to reduce bird and bat fatalities at wind energy
projects. The research provided at the NWTC will serve as a pipeline to the American

Wind Wildlife Institute’s technology verification program and similar efforts aimed at
supporting commercialization of these products.

6. POWER IN WIND:
Every moving element has a kinetic energy. When air moves with a velocity it has a kinetic
energy as well as power i.e the ability to do work at per unit time.
We know that, the power of fluid, having a mass flow rate
𝑑𝑚
𝑑𝑡
, can be represented by,
𝑃 =
1
2
𝑑𝑚
𝑑𝑡
𝑣2
Where, P = power of fluid
v = velocity of fluid
Now, the mass flow rate of a fluid with a density 𝜌 through an area of A is given by,
𝑑𝑚
𝑑𝑡
= 𝜌𝐴𝑣
Therefore, 𝑃 =
1
2
𝜌𝐴𝑣. 𝑣2
=
1
2
𝜌𝐴𝑣3
This is the expression of power of wind in terms of density, area and velocity. In this equation if
the density and area remain constant (infect the air density little bit changes in different places
and temperatures), the power of wind is exponentially changed with the change of velocity 𝑣. A
graph of power vs velocity of wind is shown below.
Fig. 6.1: power in wind vs. velocity of wind graph

From the graph above we can see that a small change in velocity can cause a large change in the
power of wind. So we have to know which things affects the wind speed. From the wind profile
we can know about wind speed.
6.1 Wind profile:
The simplest form of wind profile is the logarithmic wind profile which is given below [9]. The
parameters on which the wind speed depends can be illustrated from this relation.
𝑈(𝑍) =
u∗
𝜅
(𝑙𝑛
𝑧
zo
− 𝜓)
Where, U = Wind speed
z = Height
zo = roughness length
u* = friction or shear velocity
𝜅 = Von Karman constant (∼ 0.4)
𝜓 = atmospheric stability function
From the equation we can see that the wind speed depends on the height of wind from the
ground. If z is increased, the wind speed will increased.
There is an important term the ‘roughness length’. It depends on the property of place on which
wind blows. The lower the rough length, the bigger the wind speed. The roughness length for
different places is given below [10].

Table 6.1: roughness length at different places
From the chart we see that the roughness length is bigger in the land and smaller in the water
areas. So the wind speed is greater in the water areas than that of in the lands.
Here in the equation the stability function 𝜓. In neutral condition the stability function is zero.
Neutral condition means that there is no heat flux from the surface. During the day time 𝜓 >
0 and during the night 𝜓 < 0.
In the night and in the day the wind speed is different and it also varies with the dy condition.
Here a discussion is given below how it is occurred.

Fig. 6.3: Wind speed changes with height at different conditions of a day [10].
In the figure it is an example of wind profile. It's driven by a geostrophic wind. This case, 12
meters per second. And the geostrophic wind is a wind that drives the wind near the surface. It's
the wind speed at about 1 kilometer's height. It's characteristic that the wind varies a lot near the
surface during the day and at night.
The black curve is a neutral wind profile and in this representation here where the y axis is
Logarithmic, it can be seen as a straight line.
During the night it's difficult for the energy to come to the ground because of the reduced
momentum flux and the wind speed reduces near the ground. This is represented by the green
line. But we can also see that although the wind speed is low near the ground, it increases fairly
fast with height. And at a height of about 100 meters it can sometimes even be faster than the
neutral wind speed.
During the day there is a better of connection to the geostrophic wind. You have a higher wind
speed during the day than during the night and it is represented by the red curve. You can also
see that the wind speed varies little with height during the day, because of the large eddies and
because of the efficient mixing during the day.

So already here we can see that the wind speed during the night and the wind speed during the
day are very different, close to the surface. But we can also have an idea that about 100 meters
above, the conditions are quite different.
These are some factors on which wind speed depends.

7. DIFFERENT TYPES OF WIND TURBINE:
Wind turbines can be separated into two basic types determined by which way the turbine spins.
Wind turbines that rotate around a horizontal axis are more common (like a wind mill), while
vertical axis wind turbines are less frequently used (Savonius and Darrieus are the most common
in the group).[12] There is also a modern type of wind turbine known as ducted wind turbine
which is more efficient than the others.
7.1 Horizontal Axis Wind Turbines (HAWT):
Horizontal axis wind turbines, also shortened to
HAWT, are the common style that most of us
think of when we think of a wind turbine. A
HAWT has a similar design to a windmill, it has
blades that look like a propeller that spin on the
horizontal axis.
Horizontal axis wind turbines have the main
rotor shaft and electrical generator at the top of
a tower, and they must be pointed into the wind.
Small turbines are pointed by a simple wind
vane placed square with the rotor (blades), while
Large turbines generally use a wind sensor
coupled with a servo motor to turn the turbine
into the wind. Most large wind turbines have a
gearbox, which turns the slow rotation of the
rotor into a faster rotation that is more suitable to Fig. 7.1: Horizontal axis wind turbine
drive an electrical generator.
Since a tower produces turbulence behind it, the turbine is usually pointed upwind of the tower.
Wind turbine blades are made stiff to prevent the blades from being pushed into the tower by
high winds. Additionally, the blades are placed a considerable distance in front of the tower and
are sometimes tilted up a small amount.
Downwind machines have been built, despite the problem of turbulence, because they don't need
an additional mechanism for keeping them in line with the wind. Additionally, in high winds the
blades can be allowed to bend which reduces their swept area and thus their wind resistance.
Since turbulence leads to fatigue failures, and reliability is so important, most HAWTs are
upwind machines.

7.1.1 HAWT advantages
 The tall tower base allows access to stronger wind in sites with wind shear. In some wind
shear sites, every ten meters up the wind speed can increase by 20% and the power output
by 34%.
 High efficiency, since the blades always move perpendicularly to the wind, receiving
power through the whole rotation. In contrast, all vertical axis wind turbines, and most
proposed airborne wind turbine designs, involve various types of reciprocating actions,
requiring airfoil surfaces to backtrack against the wind for part of the cycle. Backtracking
against the wind leads to inherently lower efficiency.
7.1.2 HAWT disadvantages
 Massive tower construction is required to support the heavy blades, gearbox, and
generator.
 Components of a horizontal axis wind turbine (gearbox, rotor shaft and brake assembly)
being lifted into position.
 Their height makes them obtrusively visible across large areas, disrupting the appearance
of the landscape and sometimes creating local opposition.
 Downwind variants suffer from fatigue and structural failure caused by turbulence when
a blade passes through the tower's wind shadow (for this reason, the majority of HAWTs
use an upwind design, with the rotor facing the wind in front of the tower).
 HAWTs require an additional yaw control mechanism to turn the blades toward the wind.
 HAWTs generally require a braking or yawing device in high winds to stop the turbine
from spinning and destroying or damaging itself.
Cyclic stresses and vibration
When the turbine turns to face the wind, the rotating blades act like a gyroscope. As it pivots,
gyroscopic precession tries to twist the turbine into a forward or backward somersault. For each
blade on a wind generator's turbine, force is at a minimum when the blade is horizontal and at a
maximum when the blade is vertical. This cyclic twisting can quickly fatigue and crack the blade
roots, hub and axle of the turbines.

7.2 Vertical Axis Wind Turbines (VAWT):
Vertical axis wind turbines, as shortened to
VAWTs, have the main rotor shaft arranged
vertically. The main advantage of this
arrangement is that the wind turbine does not
need to be pointed into the wind. This is an
advantage on sites where the wind direction is
highly variable or has turbulent winds.
With a vertical axis, the generator and other
primary components can be placed near the
ground, so the tower does not need to support
it, also makes maintenance easier. The main
drawback of a VAWT generally create
drag when rotating into the wind.
It is difficult to mount vertical-axis turbines on
towers, meaning they are often installed nearer
to the base on which they rest, such as the
ground or a building rooftop. The wind speed Fig 7.2: Vertical axis wind turbine
is slower at a lower altitude, so less wind energy is available for a given size turbine. Air flow
near the ground and other objects can create turbulent flow, which can introduce issues of
vibration, including noise and bearing wear which may increase the maintenance or shorten its
service life. However, when a turbine is mounted on a rooftop, the building generally redirects
wind over the roof and this can double the wind speed at the turbine. If the height of the rooftop
mounted turbine tower is approximately 50% of the building height, this is near the optimum for
maximum wind energy and minimum wind turbulence.
7.2.1 VAWT subtypes:
7.2.1.1 Darrieus wind turbine:
Darrieus wind turbines are commonly called "Eggbeater" turbines, because they look like a giant
eggbeater. They have good efficiency, but produce large torque ripple and cyclic stress on the
tower, which contributes to poor reliability. Also, they generally require some external power
source, or an additional Savonius rotor, to start turning, because the starting torque is very low.
The torque ripple is reduced by using three or more blades which results in a higher solidity for
the rotor. Solidity is measured by blade area over the rotor area. Newer Darrieus type turbines
are not held up by guy-wires but have an external superstructure connected to the top bearing.

Fig. 7.3: Types of Darrieus wind turbines
7.2.1.2 Savonius wind turbine:
A Savonius is a drag type turbine, they are
commonly used in cases of high reliability in
many things such as ventilation and
anemometers. Because they are a drag type
turbine they are less efficient than the common
HAWT. Savonius are excellent in areas of
turbulent wind and self-starting.
Fig. 7.4: Savonius Wind turbine
7.2.2 VAWT advantages
 No yaw mechanisms is needed.
 A VAWT can be located nearer the ground, making it easier to maintain the moving
parts.
 VAWTs have lower wind startup speeds than the typical the HAWTs.
 VAWTs may be built at locations where taller structures are prohibited.
 VAWTs situated close to the ground can take advantage of locations where rooftops,
mesas, hilltops, ridgelines, and passes funnel the wind and increase wind velocity.

7.2.3 VAWT disadvantages
 Most VAWTs have an average decreased efficiency from a common HAWT, mainly
because of the additional drag that they have as their blades rotate into the wind. Versions
that reduce drag produce more energy, especially those that funnel wind into the collector
area.
 Having rotors located close to the ground where wind speeds are lower and do not take
advantage of higher wind speeds above.
 Because VAWTs are not commonly deployed due mainly to the serious disadvantages
mentioned above, they appear novel to those not familiar with the wind industry. This has
often made them the subject of wild claims and investment scams over the last 50 years.
7.3 Ducted wind turbines:
The performance of a turbine in a duct having a convergent and a divergent surface is enhanced
by controlling the fluid flow pattern along the inner duct surface. For this purpose a free rotor
redistributes part of the inner fluid stream through a ring into the outer stream to prevent
premature separation of the inner stream from the divergent duct surface. The turbine and rotor
are driven by distinct fluid streams that are separated by a duct [13].
Fig. 7.5: Ducted Wind turbine and its principle.
7.3.1 Advantages:
 Less visual impact on buildings architecture than traditional HAWT or VAWT turbines

 Make use of unused roof space in cities
 Allows energy need to be met on-site avoiding transmission losses associated with
centralized energy generation.
7.3.2 Disadvantages:
 Suitable for urban environments, but not households (only effective on urban high-rise
buildings)
 Uni-directional, Fixed position and are dependent upon wind blowing in the correct
direction
 Much more research and development is needed. Research in this field is growing as
people become more interested in urban wind generation.
 Research has to be done to determine energy production potential.

8. THE INSIDE OF A WIND TURBINE:
The energy in the wind turns two or three propeller-like blades around a rotor. The rotor is
connected to the main shaft, which spins a generator to create electricity. There is an illustration
below which provides a detailed view of the inside of a wind turbine, its components, and their
functionality.[11]
Fig. 8.1: Different components of a Wind turbine
i. Anemometer:
Measures the wind speed and transmits wind speed data to the controller.
ii. Blades:
Lifts and rotates when wind is blown over them, causing the rotor to spin. Most turbines
have either two or three blades.
iii. Brake:
Stops the rotor mechanically, electrically, or hydraulically, in emergencies.
iv. Controller:
Starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off
the machine at about 55 mph. Turbines do not operate at wind speeds above about 55
mph because they may be damaged by the high winds.
v. Gear box:
Connects the low-speed shaft to the high-speed shaft and increases the rotational speeds
from about 30-60 rotations per minute (rpm), to about 1,000-1,800 rpm; this is the
rotational speed required by most generators to produce electricity. The gear box is a

costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive"
generators that operate at lower rotational speeds and don't need gear boxes.
vi. Generator:
Produces 60-cycle AC electricity; it is usually an off-the-shelf induction generator.
vii. High-speed shaft:
Drives the generator.
viii. Low-speed shaft:
Turns the low-speed shaft at about 30-60 rpm.
ix. Nacelle:
Sits atop the tower and contains the gear box, low- and high-speed shafts, generator,
controller, and brake. Some nacelles are large enough for a helicopter to land on.
x. Pitch:
Turns (or pitches) blades out of the wind to control the rotor speed, and to keep the rotor
from turning in winds that are too high or too low to produce electricity.
xi. Rotor:
Blades and hub together form the rotor.
xii. Tower:
Made from tubular steel (shown here), concrete, or steel lattice. Supports the structure of
the turbine. Because wind speed increases with height, taller towers enable turbines to
capture more energy and generate more electricity.
xiii. Wind direction:
Determines the design of the turbine. Upwind turbines—like the one shown here—face
into the wind while downwind turbines face away.
xiv. Wind vane:
Measures wind direction and communicates with the yaw drive to orient the turbine
properly with respect to the wind.
xv. Yaw drive:
Orients upwind turbines to keep them facing the wind when the direction changes.
Downwind turbines don't require a yaw drive because the wind manually blows the rotor
away from it.
xvi. Yaw motor:
Powers the yaw drive.

9. ONSHORE AND OFFSHORE WIND TURBINES:
On the basis of place of setting up the turbine there are two types of wind turbine. One is onshore
wind turbine and the other is offshore wind turbine and another term, the near shore, is
sometimes added also.
The onshore wind turbines are set up on the land and the offshore wind turbines are set up over
the sea. Both of these two turbines have their advantages and disadvantages which is described
below.
9.1 Onshore Wind turbines:
Onshore Wind power is a well-established source of energy that provides clean, sustainable
power to many countries around the world. In 2014, in operation worldwide 240,000 commercial
size wind turbine producing 4% of the world’s electricity. Onshore installed wind power capacity
is 421,000 MW worldwide which is enough to power 38 Million American households for a year
[27].
Fig. 9.1: Onshore Wind Turbines
Because of increasing attention we are going to weigh up what we see as the potential
advantages and disadvantages of this form of renewable technology.

9.1.1 Advantages:
 People are familiar with onshore wind. We can point to many examples around the world
of how successful onshore wind can be. Denmark is receiving over 40 percent of their
electricity from wind and 75 percent of that comes from onshore turbines.
 A regular onshore turbine last for around 20 years
 Normally it takes about 2-3 months before the wind turbine has paid itself back. This also
includes the energy, which were used to produce, install, maintain and remove the wind
turbine.
 The infrastructure necessary to transmit electricity from onshore turbines is considerably
less expensive than that of offshore. Onshore wind is also competitive in the greater
renewable market, as it is the cheapest form currently available.
 Onshore turbine production could act as a boost to local economies. If turbines are
installed closer to their manufacturing sites, their value is likely to stay closer.
 There would be less emissions from transporting wind structures if they are installed
closer to the manufacturing site.
 Onshore wind speeds are more unpredictable than offshore. Because turbines are
optimized at a specific speed, they could lose efficiency if wind is too slow or too fast.
 Wind turbines are noisy. Each one can generate the same level of noise as a family car
travelling 70 mph
 Onshore wind direction changes much more often. Turbines must be facing the direction
of the wind to operate efficiently. Advances in technology have led to new turbines that
have some ability to pivot towards the wind.
 Onshore wind turbines are often criticized for their visual impact, ruining what
previously have been areas of natural beauty. They are typically spread out over larger
areas than other energy producing installations, and therefore have a larger impact on the
local environment.
9.2 Offshore Wind turbines:
Many coastal areas have very high energy needs. Offshore wind farms have many of the same
advantages as land-based wind farms – they provide renewable energy; they do not consume
water; they provide a domestic energy source; they create jobs; and they do not emit
environmental pollutants or greenhouse gases. The number of offshore wind turbines in Europe
at the end of 2016 is 3,589. The amount of offshore wind power installed globally at the end of
2016 is 14,384 Gigawatt [26].
The advantages and disadvantages of offshore wind turbine is discussed below.

Fig. 9.2: Offshore Wind turbines
9.2.1 Advantages:
 Offshore wind speeds tend to be faster than on land. Small increases in wind speed yield
large increases in energy production: a turbine in a 15-mph wind can generate twice as
much energy as a turbine in a 12-mph wind. Faster wind speeds offshore mean much
more energy can be generated.
 Offshore wind speeds tend to be steadier than on land. A steadier supply of wind means a
more reliable source of energy.
 Many coastal areas have very high energy needs. 53% of the United States’ population
lives in coastal areas, with concentrations in major coastal cities. Building offshore wind
farms in these areas can help to meet those energy needs from nearby sources.
 Offshore wind farms have many of the same advantages as land-based wind farms – they
provide renewable energy; they do not consume water; they provide a domestic energy
source; they create jobs; and they do not emit environmental pollutants or greenhouse
gases.
 Offshore wind farms can be expensive and difficult to build and maintain. In particular:

 It is very hard to build robust and secure wind farms in water deeper than around 200
feet (~60 m), or over half a football field’s length. Although coastal waters off the
east coast of the U.S. are relatively shallow, almost all of the potential wind energy
resources off the west coast are in waters exceeding this depth.
 Wave action, and even very high winds, particularly during heavy storms or
hurricanes, can damage wind turbines.
 The production and installation of power cables under the seafloor to transmit
electricity back to land can be very expensive.
 Effects of offshore wind farms on marine animals and birds are not fully understood.
 Offshore wind farms built within view of the coastline (up to 26 miles offshore,
depending on viewing conditions) may be unpopular among local residents, and may
affect tourism and property values.
9.3 Offshore or Onshore which one is suitable?
As we discussed above the wind power in the water areas is greater than that of in the lands [art.
6.1], it is clear that the offshore wind turbines are more efficient than the onshore wind turbines.
But the offshore wind turbine farms are more expensive than the onshore ones. So it can be said
that each turbine is suitable for different places and different situations.
Onshore wind turbines are suitable for the places where enough free places with strong wind
exist. But it is difficult for a country with a big population to manage such place. On the other
hand onshore places where the wind is strong and durable are not so available.
Fig. 9.3: The coastal area of Monaco

Offshore wind turbine are the best energy solution for the places which is densely populated but
have a large coastal area. But the most critical thing that have to be bear in mind is the
stabilization of an offshore wind turbine. To minimize the cost and attain the biggest power from
an offshore wind turbine, it have to be made floating.

10. STABILIZATION OF AN OFFSHORE FLOATING WIND TURBINE:
Much of the offshore wind resource potential in the United States, China, Japan, Norway, and
many other countries is available in water deeper than 30 m. In contrast, all the European
offshore wind turbines installed to date are on fixed-bottom substructures. These turbines have
mostly been installed in water shallower than 20 m by driving monopoles into the seabed or by
relying on conventional concrete gravity bases. These technologies are not economically feasible
in deeper water. Instead, space-frame substructures, including tripods, quad pods, or lattice
frames (e.g., “jackets”), will be required to maintain the strength and stiffness requirements at the
lowest possible cost. The Beatrice Wind Farm Demonstrator Project in the North Sea near
Scotland, where two 5-MW wind turbines are being installed on a jacket structure in 45 m of
water, is a good example of this technology. At some depth, however, floating support platforms
will be the most economical. This natural progression is illustrated in Figure [14]. Without
performing a dynamic analysis, Musial, Butterfield, and Boone [15] have demonstrated the
economic potential of one floating platform design.
Fig. 10.1: Natural progression of substructure designs from shallow to deep water
Numerous floating support platform configurations are possible for offshore wind turbines,
particularly considering the variety of mooring systems, tanks, and ballast options that are used

in the offshore oil and gas (O&G) industries. Figure illustrates several of these concepts, which
are classified in terms of how the designs achieve static stability. The spar-buoy concept, which
can be moored by catenary or taut lines, achieves stability by using ballast to lower the center of
mass (CM) below the center of buoyancy (COB). The tension leg platform (TLP) achieves
stability through the use of mooring-line tension brought about by excess buoyancy in the tank.
In the barge concept, the barge is generally moored by catenary lines and achieves stability
through its water-plane area. Hybrid concepts, which use features from all three classes, are also
a possibility [16].
Fig. 10.2: Floating platform concepts for offshore wind turbines
Because the offshore O&G industries have demonstrated the long-term survivability of offshore
floating structures, the technical feasibility of developing offshore floating wind turbines is not in
question. Developing cost-effective offshore floating wind turbine designs that are capable of
penetrating the competitive energy marketplace, though, will require considerable thought and
analysis. Transferring the offshore O&G technology directly to the offshore wind industry

without adaptation would not be economical. These economic challenges impart technological
challenges [16], which, in turn, must be addressed through conceptual design and analysis.
In the offshore environment, additional loading is present, and additional dynamic behavior must
be considered. Wave-induced (diffraction) and platform-induced (radiation) hydrodynamic loads,
which are the most apparent new sources of loading, impart new and difficult challenges for
wind turbine analysts. Additional offshore loads arise from the impact of floating debris or sea
ice and from marine growth buildup on the substructure. The analysis of offshore wind turbines
must also account for the dynamic coupling between the motions of the support platform and the
wind turbine, as well as for the dynamic characterization of the mooring system for compliant
floating platforms.

11. Global Status of Wind Power:
Fig. 11.1: Annual Installed Capacity by Region 2008-2016 [26]
Wind Power Chalks Up More Strong Numbers.
The 2016 market was more than 54.6 GW, bringing total global installed capacity to nearly 487
GW. Led by China, the US, Germany, and India; and with surprisingly strong showings from
France, Turkey and the Netherlands, the global market was nonetheless less than 2015’s record
total.
“Wind power continues to grow in double digits; but we can’t expect the industry to set a new
record every single year”, said Steve Sawyer, GWEC Secretary General. “Chinese installations
were an impressive 23,370 MW, although this was less than 2015’s spectacular 30GW, which
was driven by impending feed-in tariff reductions. Also, Chinese electricity demand growth is
slackening, and the grid is unable to handle the volume of new wind capacity additions; although
we expect the market to pick up again in 2017.” The Chinese offshore market began what many

hope is the sector’s long awaited take-off in 2016, with China passing Denmark to achieve
3rd
place in the global offshore rankings, after the UK and Germany.
US installations (8,203 MW) were nearly equal to 2015’s strong market, bringing the US total to
more than 82 GW. The US industry now employs more than 100,000 people and has more than
18 GW under construction or in advanced stages of development, a harbinger for a strong market
again in 2017. Canada (702 MW) and Mexico (454 MW) posted solid though modest gains.
India set a new national record with 3,612 MW of new installations, 2016’s 4th
largest market;
this brings the country’s total to 28,700 MW, consolidating its 4th
position in total cumulative
installations as well. “We have great expectations for the Indian market” continued Sawyer, “and
we look forward to seeing offshore making a contribution in India in the next few years.”
Europe had a surprisingly strong year, given the policy uncertainty which plagues the region,
posting modest gains with an annual market of 13,926 MW of which the EU-28 contributed
12,491 MW. Germany also had another strong year, installing 5,443 MW to bring its total
capacity to more than 50 GW, only the third country to reach that milestone. France had a strong
year with more than 1,500 MW, and Turkey broke the 1 GW barrier for the first time, installing
1,387 MW. The Netherlands entered the global top 10 in terms of annual market for the first
time, with 887 MW, most of which was offshore.
“The cost of wind power continues to plummet, and this is particularly the case for the European
offshore sector, which has met and exceeded its 2020 price targets by a substantial margin, and
five years early”, according to Sawyer.
Brazil once again led the Latin America market, although the country’s political and economic
woes resulted in a market which barely cleared 2 GW (2,014 MW), but which still pushed the
country over the 10 GW mark as it ended the year with 10,740 MW. Chile posted a record year
with 513 MW installed, bringing the country’s total to 1,424 MW, and Uruguay added 365 MW
for a year-end total of 1,210 MW. Peru (93 MW), the Dominican Republic (50 MW) and Costa
Rica (20 MW) also had significant installations last year. While Argentina had no new
installations in 2016, it now has a solid pipeline of more than 1,400 MW which will be built out
over the next couple of years.
Africa was quiet, with only 418 MW installed in South Africa, whose Renewable Power
Program is currently being held hostage to a power struggle between the president, his cronies
and Eskom on the one hand; and the energy regulator, the Ministry and the industry on the other.
Elsewhere, Morocco had a successful auction for 800+ MW of wind which will be built out over
the coming years, construction was nearly finished on the Lake Turkana project in Kenya; but
Egypt’s renewable ambitions seem to be stuck for the moment.

The Asia Pacific region was also quiet, with only Australia adding capacity (140 MW) although
there are signs of a strong revival in the Australian market.
“Overall, the industry is in pretty good shape” concluded Sawyer, “with new markets emerging
across Africa, Asia and Latin America, and the traditional markets in China, the US and
Germany continuing to perform well. We look forward to a strong 2017.”

12. WIND ENERGY POTENTIAL IN BANGLADESH:
Bangladesh is a small country in South Asia with a large population. As Bangladesh is a
developing country its energy demand is increasing at a significant rate. But the supply of energy
is less than the demand.
Table 12.1: Peak demand and peak generation 2008 – 2014 [17].
The primary electricity generation increased rapidly as can be seen in table 12.1 , with natural
gas and coal consumption growing at the fastest rates.
Fig. 12.1: Energy generation by source in Bangladesh in 2013 [18].

The amount of natural gas is not enough to support the present energy demand. Moreover, this
demand is constantly increasing. To meet actual demand, the Government of Bangladesh (GoB)
has established quick rental projects which are mainly dependent on diesel and furnace oil.
Besides these fossil resources, there is a small amount of hydroelectric power source in Kaptai
(figure 12.2).
The available sources are not enough to meet the challenge. To meet this drastically increasing
the sources of renewable energy like wind energy, solar energy etc. can play an important rule.
Fig. 12.2: Diversity in energy production sector [25].
To setting up different types of renewable energy plants first it has to be discussed about the
opportunity. The wind energy potential is discussed below.
12.1 Wind resources:
With its sub-tropical climate, with monsoon and typhoon seasons, Bangladesh is confronted with
large amounts of rainfall and periodically high wind speeds (gusts) during typhoon season. The
mean annual wind speeds in Bangladesh are not well documented and few data is available. The
readily available data shows that low wind speeds predominate on the Bangladeshi lands. Next to
onshore wind speeds, no (extensive) data is readily available concerning (far) offshore wind
speeds.
The ‘Solar and Wind Energy Resources Assessment’ initiative also calculated the annual wind
speeds in Bangladesh, this at a height of 50 meter. The data is shown in figure 11.4. The
maximum annual onshore wind speeds at 50 meters in Bangladesh do not outreach 5 meters per

second, and 6 meter per second for offshore wind. These can be considered as low wind
resources. During the typhoon season however, there can be wind gusts with speeds well over 35
meters per second (>1 26 km/h) [19].
Fig. 12.3: Annual wind speeds in Bangladesh [20].
US Government's Enhancing Capacity for Low Emission Development Strategies (EC-LEDS)
conducts a project consists of 9 sites where a two year wind speed metering program is in
progress at heights between 20 and 200 meters (with a met mast at 20, 40, 60 and 80 meters and
two SODAR’s up to 200 meters). The preliminary results of the measurement campaign are still
under embargo with the Ministry of Power. Final results of the measurement campaign are
expected to become public in 2018.
Also Vestas, a Danish wind turbine manufacturer, has been performing wind monitoring and site
assessments in Bangladesh; these results are not made public.

12.2 Available space for wind farms:
12.2.1 Onshore:
Bangladesh is a densely populated country and being situated in the Bengal Delta, which makes
large areas not usable for most activities, results in land being a scarce commodity. The vast
majority of the country is used for agricultural purposes (maintained by irrigation processes).
Bangladesh consists mainly of flat lands. Three-quarters of the land has no elevation higher than
30 meters. The north and southeast are more elevated, in which the division of Chittagong is the
most elevated land of the country.
In 2015 an assessment of electricity generating renewable energy technologies was carried out
with regards to the Investment Plan for the World Bank ‘Scaling up Renewable Energy Program’
(SREP). Several potential viable sites were identified and are shown in figure 3.4 Wind data was
derived from AWS Truepower Wind Navigator (2015). For a site to be potentially viable it is
required to be located within 20 km of a transmission line (see also paragraph 2.2.2). Land not
suitable for wind farm installation was excluded from the assessment such as steepness of the
land and flooding. Flooding is a concern for wind farms because softening of the soil could
compromise the foundation of the turbines. Two cases were developed by combining wind speed
data with GIS flood data, showing the resource potential when flood prone land is excluded
(Case 1) and when it is included (Case 2) [21].
Fig. 12.4: Result of assessment within SREP (Case 1 excl. flood prone land, Case 2 is included)

The resource data is an extrapolation of existing data. Although based on actual measurements, it
is not an accurate reproduction of the actual yearly average wind resources. Based on this
assessment, and a capacity factor between 20/25% and 25/30%, the following results were
presented in the SREP Investment Plan (table 3.1).
Table 12.2: Result of assessment within SREP (Case 1 excl. flood prone land, Case 2 is
included)
12.2.2 Accessibility of the terrain:
Large parts of Bangladesh are not well accessible with large trucks to transport modern wind
turbine parts, due to infrastructure limitations. An advantage is however the presence of rivers
that might be usable for transportation of heavy and large components.
12.2.3 Offshore:
As it is discussed above that the offshore wind turbines are the best solution the need of energy
for the countries which are densely populated and have a large water area. Bangladesh is such a
country which has a large coastal area, many river and large sea area in the Bay-of-Bangle.

Fig. 11.5: Bathymetry lines of Bangladeshi Bengal Bay [22]
With the active Ganges, the Brahmaputra and the Meghna rivers, fluvial sedimentation processes
are current throughout the coastal line, with an exception off of the Chittagong coast. Partly by
these processes, the first kilometers from the coast are relatively shallow. The 20 meter depth
line is at its farthest ca. 110 kilometers from the coast of Patuakhali (see figure 11.6). Being
fluvial sedimentation, it is anticipated that the soil of the seabed mainly consists of mud and
loose sand. Offshore form the Chittagong division, the sedimentation processes seem to be of a
lesser strength, but therefore the seabed is deeper, closer to shore. Next to this presumed solid
seabed, the harbor of the City of Chittagong is also nearby, which can be a useful base for
offshore contractors.
12.3 Wind energy projects:
Bangladesh began its first wind power project in 2005. There are two wind power generation
projects in Bangladesh, the Muhuri Dam wind power project and the project in Kutubdia Island.
Muhuri Dam Project is the first grid-connected wind plant in Bangladesh. The estimated annual
production from this 4×225 kW wind plant is about 2 GWh (for an equivalent of 2,500 hours of
full load/year). Kutubdia Island is Bangladesh’s other wind battery hybrid project located in

Chittagong. It produces 50×20 kW with estimated annual production of 2 Gwh (for an equivalent
of 2,500 hours of full load/year) [23].
12.3.1 Ongoing Projects:
Steps have been taken to install a 15 MW Wind Power Plant across the coastal regions of
Bangladesh after 1 year Wind Resources Assessment in Muhuri Dam Area of Feni,
Mognamaghat of Cox’sbazar, Parky Beach of Anwara in Chittagong, Kepupara of
Borguna and Kuakata of Patuakhali. Wind Mapping is going on at Muhuri Dam area of
Feni and at Mognamaghat of Cox’s bazar by Regen Powertech Ltd. of India [23].
Fig. 11.6: Wind turbines in Muhuri Dam Area of Feni.
Installation of Wind Monitoring Stations at Inani Beach of Cox's bazar, Parky Beach of
Anwara, Sitakundu of Chittagong and at Chandpur under USAID TA project is underway
[23].
7.5 MW off Grid Wind-Solar Hybrid System with HFO/Diesel Based Engine Driven
Generator in Hatiya Island, Noakhali [23].
12.3.2 Projects under Planning:
The following statements were found at www.bpdp.gov.bd. Further information on scope,
planning and actual status is absent.

BPDB has planned to implement 50-200 MW Wind Power Project at Parky Beach area,
Anawara in Chittagong on IPP basis [24]
BPDB has also planned to expand onshore wind power plants along the coastline of
coastal regions of Bangladesh [24].
In interviews held in Dhaka, August 2016, it became clear that no large scale wind energy
projects are on their way at the moment. Some projects have been started up but have been
cancelled due to a lack of mutual understanding between government and developer on the
power purchase agreement (PPA).

13. CONCLUSION:
In this report the history of using wind energy has been discussed. The causes of wind flow and
the power in wind has been illustrated. The wind turbines, its different types and their advantages
disadvantages, its construction has been described in details. The offshore and onshore wind
turbines were discussed here and the challenges of offshore wind turbines are described briefly.
The present global status of wind energy have also been mentioned. And finally the wind energy
potential and opportunities have been discussed.

REFERENCES
1. GTZ (2000) Wind Energy Projects in Morocco and Namibia. Eschborn, retrieved
08.01.2013 https://www.docstoc.com/pass/22042181]
2. GTZ (2000) Wind Energy Projects in Morocco and Namibia. Eschborn, retrieved
08.01.2013 [1]
3. Kaldellis J.K. (2010) Overview of stand-alone and hybrid wind energy systems, in:
Kaldellis J.K. (2010) Stand-alone and hybrid wind energy systems, Woodhead publishing
4. GTZ (2009) TERNA Wind Energy Programme 1997-2009 – Impact Report –. Eschborn,
Germany, retrieved 25.7.2011 [[2]]
5. Lucas, Adam (2006). Wind, Water, Work: Ancient and Medieval Milling Technology.
Brill Publishers. p. 105. ISBN 90-04-14649-0.
6. Lucas, Adam (2006). Wind, Water, Work: Ancient and Medieval Milling Technology.
Brill Publishers. p. 105. ISBN 90-04-14649-0.
7. www.metoffice.gov.uk
8. https://earth.nullschool.net
9. Tennekes, H. "The logarithmic wind profile." Journal of the Atmospheric Sciences 30.2
(1973): 234-238.
10. www.coursera.org
11. https://energy.gov/
12. http://centurionenergy.net/types-of-wind-turbines
13. Gaskell, Christopher Norman. "Ducted wind turbine." U.S. Patent No. 7,018,166. 28
Mar. 2006.
14. Musial, W. and Butterfield, S., “Future for Offshore Wind Energy in the United States,”
EnergyOcean Proceedings, June 2004, Palm Beach Florida, USA, NREL/CP-500-36313,
Golden, CO: National Renewable Energy Laboratory.
15. Musial, W., Butterfield, S., and Boone, A., “Feasibility of Floating Platform Systems for
Wind Turbines,” A Collection of the 2004 ASME Wind Energy Symposium Technical
Papers Presented at the 42nd AIAA Aerospace Sciences Meeting and Exhibit, 5–7
January 2004, Reno Nevada, USA, New York: American Institute of Aeronautics and
Astronautics, Inc. (AIAA) and American Society of Mechanical Engineers (ASME),
January 2004, pp. 476–486, NREL/CP-500-36504, Golden, CO: National Renewable
Energy Laboratory.
16. Butterfield, S., Musial, W., Jonkman, J., Sclavounos, P., and Wayman, L., “Engineering
Challenges for Floating Offshore Wind Turbines,” Copenhagen Offshore Wind 2005
Conference and Expedition Proceedings, 26–28 October 2005, Copenhagen, Denmark
[CD-ROM], Copenhagen, Denmark: Danish Wind Energy Association, October 2005,
NREL/CP-500-38776, Golden, CO: National Renewable Energy Laboratory.
17. Annual report Bangladesh Power Development Board.
18. (source: EIA).

19. Solar and Wind Energy Resources Assessment.
20. (source: NREL, 2007)
21. ‘Scaling up Renewable Energy Program’ (SREP) by World Bank.
22. (source: USGS, 2001).
23. Maarten Jaspers Faijer, Eric Arends . “Wind energy potential Bangladesh” (4th
April,
2017) Netherlands Enterprise Agency, 716044.
24. www.bpdp.gov.bd.
25. http://www.mpemr.gov.bd/news/details/774.
26. Global Wind Energy Council report 2016.
27. https://www.siemens.com/global/en/home/markets/wind/onshore.html

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