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					Wind           Energy


       Wind Energy
       Introduction
 Renewable energy course
Supervisor: Prof. Göran Wall
       Huijuan Chen
         Sep. 2006
[1]
Table of contents:


Introduction...............................................................................................5
    1.1 Wind resources ..............................................................................5
        1.1.1Origin of wind.........................................................................5
        1.1.2 World wind distribution .........................................................6
        1.1.3 Map of available wind energy ...............................................7
        1.1.4 Wind power class ...................................................................8
        1.1.5 The Wind as a Source of Energy ...........................................9
    1.2 The markets of wind power .........................................................9
        1.2.1 The wind power in the world.................................................9
        1.2.2 The wind power in china .....................................................12
Reference: ................................................................................................15
Foreword


According to the scientific
research on climate change,
more and more data suggest
that    carbon      dioxide
emissions     and     other
greenhouse gases could
increase    the     average
temperature and result in
global warming. It also
indicates that those gases can affect ecosystems, weather patterns, water resources,
and even cause the extreme climate. At the same time global energy demand is
growing, while the conventional fossil fuels, such as coal, oil and natural gas, are in

the situation of decreasing. Taking all these factors into consideration,we can arrive

the conclusion that searching and using renewable energy is imperative under the
situation. Nowadays many countries have done much work on the goal achieving the
sustainable supply, they are actively promoting the usage of renewable energy and
getting the greatest benefit from energy.
Wind energy is one of the leading renewable energy resources that are not exhausted
over time. It is a good resource for the reason that it can not only produces little or no
polluting emissions, but also can help to meet the growing energy demand .Over the
last decade ,the use of wind energy has increased remarkably. Currently there are
more than 20,000 wind turbines installed world-wide that provide electricity
generation. Wind energy and its advanced conversion technologies have become more
and more mature; it is able to compete with the traditional energy and has a bright
future in the energy market.
Chapter 1


Introduction


1.1 wind resources
1.1.1 Origin of wind
Wind is a kind of simple air motion .It is caused by the unequal heating of the earth
surface .Since the earth surface is made of different kinds of continents and oceans, it
absorbs the sun heat at different rates, and the different temperature could cause the

                                                                                 as
different pressure .During the day, the air above the land heats up more quickly, we

all know ,the warm air is light ,and it will expand and rise causing a low pressure
area ,where the heavier cooler air above the water will rush into and fill with, thus
creates a surface wind. However, at night, it is reversed because the air cools more
fastly over land than over water




                   Figure1:Where dose the wind come from [3]
1.1.2 World wind distribution
Wind is an intermittent resource, and it is difficult for us to locate the space that the
wind circulates, because the wind pattern is affected by many factors, including the
geographic factors, such as the seasons change, day and night change, humidity, the
irregular reflectivity of land and water and so on. As result, these effects could
complicate the flow of wind over the surface.




                        Figure 2: The global wind circulation [4]

Although there are many factors involving the wind pattern, we can identify the three
major wind belts in the world. It is classified according to the direction its blowing.
1. The first one is called the doldrums, which is the region that near the equator. It is
the intertropical convergence space where the hemispheres trade winds meet, and it
has calm wind in extremely low pressure.
2. The second one is a high-pressure area which lies about 30o latitude. In the region,
the two kinds of winds which are trades and westerlies separate from each other, and
they respectively flow toward the equator and pole direction. The belt is different
from the doldrums, it has little wind.
3. The third one is called the polar front, which lies about 60o latitude. However, for
the reason that the polar front flow towards south in winter and north in summer, so
the belt varies with the change of seasons.      There exists a great difference pressure,
for the contacting of polar easterlies and prevailing westerlies, the former is cold,
while the latter is hot, so it is easily to form the wind.


1.1.3 Map of available wind energy
From the above information, we’ve already know the global wind circulation, and it is
available for us to estimate the amount of the wind energy that can be used. Now
there is a map can be shown, it is “world-wide wind energy distribution
estimates”[12]
In the following figures, the white area means there is little wind energy, and the dark
blue means rich.




                 Figure 3: Wind resource in the Western Hemisphere [5]
             Figure 4: Wind Resource in the Eastern Hemisphere [6]

1.1.4 Wind power class




          Table 1: Classes of wind power density at 10 m and 50 m [7]
For example, Wind Power Class = 3 represents the Wind Power density range
between 150 W/m2 and 200 W/m2. [13]
Wind speeds generally increase with the height above sea level and the height above
ground. The power in the wind that available to us increases with the cube of the wind
speed. If the wind speed doubles, we are able to get the available power as much as an
eight times increase. Therefore, an average wind speed of 5 meters per second (m/s)
contains nearly twice power at 4m/s. [14]




1.1.5 The Wind as a Source of Energy
Wind is called a renewable energy source because the wind will blow as long as the
sun shines. It has been harnessed for thousands of years .The wind’s kinetic energy
can be converted into other forms of energy, either electrical energy or mechanical
energy .One of the oldest uses of wind energy is transportation, people use it to sail
ships ,and farmers also have been using wind energy to pump water ,grind grain.
More recently, it has been widely used for special purposes in the world, such as
generating electricity, and modern wind turbines are the machines which are
extremely efficient converting the wind energy into electricity. The existing
technology can offer different power ratings from a few kilowatts to several
megawatts. The areas in which the wind power density is at least 400 W/m2 at 30
meters above the ground wind resources can be available.




1.2 The markets of wind power
1.2.1 The wind power in the world
As wind technology has matured, the wind energy global market has been growing
rapidly. By the end of 2004, the capacity of wind energy installed globally had
reached the level of almost 48,000 MW. Europe accounts for 72% of the total

installed capacity,and other countries are taking their steps to develop the large-scale

commercial markets. In the world, more than 50 countries now contribute to the
global total wind market, and many people have been employed by the industry, the
number is estimated to be 90-100,000 worldwide. There are 8-10 primary countries
which take up the most part of the wind energy market; they are Denmark, Germany,
India, Italy, Netherlands, Spain, the United Kingdom, and the United States. [15]
Europe is the leader in the wind energy market; it has been growing during the past 6
years. Within Europe, Spain became the new market leader, with 2,064 MW of
capacity installed during 2004. It was closely followed by Germany, with 2,054 MW.
Germany still has the largest cumulative capacity both in Europe and global, with a
total of 16,649 MW by the end of the year. And recently, the European Wind Energy
Association has revised its wind capacity projections in 2010 which is from
4x104MW to 6x104MW.
In the United States, American market experienced a reduction of the global growth
rate during 2004. Now, its total capacity has reached 6,750 MW. Canada, with one of
the largest wind resources in the world, is looking increasingly promising as a market.
A total of 444 MW had been reached by the end of 2004, and many large projects are
progressing fast.
In Asia, the Indian market has revived strongly in the late 1990s. During 2004, almost
900 MW was installed, the third largest country market, taking the total up to 3,000
MW. Japan also registered an improved performance in 2004, reaching a total of 991
MW, whilst China moved up to 769 MW.
In Africa, both Egypt and Morocco have shown what is possible with national
planning and the backing of European developers. Morocco already gets 2% of its
electricity from a 50 MW wind farm and tenders exist for another 200 MW,
Egypt is continuing to develop sites along the Red Sea coast with the support
of German, Japanese and Danish aid agencies.[16]
 Figure 5: Top ten wind power markets 2004: annual MW installed [8]




Figure 6: Top ten wind power markets 2004: cumulative MW installed [9]
     Figure 7: Cumulative installation MW in the top ten wind power markets [10]


1.2.2 The wind power in china
China has the long history of using wind energy to generate electricity. It is the
country with the huge land and long coastline, which is abundant in wind energy. In
china, the areas rich in wind resources are mainly located along the southeast coast,
nearby islands and in Inner Mongolia, Xinjiang, Gansu Province’s Hexi Corridor, and
in some parts of Northeast China, Northwest China, North China and the
Qinghai-Tibetan Plateau. [17]
In recent years, the Chinese government has realized it is important to develop wind
power, because the electricity demand is increasing, and the pollution caused by fossil
fuel has become more and more serious. So, in 1994, the Chinese former Ministry of
Electric Power made a decision that developed wind farms as a new clean power
source. Now China has gained a great achievement in wind power development .By
the end of 2005, total installations had reached 1260 MW with an annual growth of 60
%.
Figure 8: Installed capacity of wind power in china [11]


From the achievements of using wind energy, China has shown the great interesting in
renewable energy. Although the cleaner coal-based technologies can reduce the
pollution and satisfy the electricity demand, the government seems to put official
hope in renewable energy, and sets the wind power target: its generation capacity
should account 12% in the total renewable energy generation capacity by 2020. In 14
provinces, more than 40 wind farms had been established up to December 2003;and
1042 wind turbines contribute to a total capacity of 567.4 MW. This action not only
reduces the reliance on foreign oil but also contributes China to be one of the leaders
in wind energy. Wind could become China's second-largest source of electricity
However, we should see some problems in China’s wind power development, such as
high price, high cost, low demand and small scale. There are several reasons can
account for them.
Although we have taken some actions to reduce the high taxation on wind power
operators, the tax from value-added and income for wind farms are higher than
ordinary power plants. So it is the tough thing for the operators to get low interest and
long term loan from commercial bank, and those banks consider wind power is a risk
industry. Also, there is a case in China which is normal in other western countries,
that is no favorable policy can allow wind power operators to accelerate the
depreciation of their facilities.
In addition, environment costs are not included in electricity generated by ordinary
power plant; cheap ordinary power electricity restrained the demand for cleaner but
more expensive wind power. Although utilizing wind power benefits the whole
society, the costs are carried by local power grid company. There is no mechanism to
share the cost among all the electricity consumers in the country.
Here, for the development of wind power in China we have some suggestions.
• Cut down tax rate.
• Assist financing activity of wind farm operators.
• Give subsidy to wind farms.
• Enforce power grid company to purchase the electricity generated by wind farms
through legislation.
• Determine wind power electricity price by market mechanism.
• Establish green certificate market to realize the environmental value of wind power
electricity.
In china ,the largest wind farm (100 MW) is under construction; the on-grid price had
been reduced to reasonable RMB0.478 /kwh, and the wind power capacity target in
2010 is 3,000 MW .we are happy to see these, and the future of China’s wind power
generation is bright
             Reference:
Figures:
[1] From the sustainability of wind energy A Global approach to wind power
[2] http://www.re-energy.ca/pdf/wind-energy-bg.pdf
[3] http://www.eia.doe.gov/kids/energyfacts/sources/renewable/wind.html
[4] From the sustainability of wind energy A Global approach to wind power
[5] From the sustainability of wind energy A Global approach to wind power
[6] From the sustainability of wind energy A Global approach to wind power
[7] From the sustainability of wind energy A Global approach to wind power
[8] http://www.gwec.net/index.php?id=49
[9]http://www.gwec.net/index.php?id=49
[10] http://www.gwec.net/index.php?id=49
[11]http://www.newenergy.org.cn/html/2004-12/20041611.html
Contents:
[12] From the sustainability of wind energy A Global approach to wind power
[13] From the sustainability of wind energy A Global approach to wind power
[14] From the sustainability of wind energy A Global approach to wind power
[15] Wind force 12
[16] http://www.ewea.org/index.php?id=196
[17]Management of Energy Resources in China
Conclusion
                              (Huijuan Chen)
In the part of introduction, we introduce some basic knowledge of
wind, wind energy and the wind market.
Wind is a simple air motion, it is mainly caused by the temperature
difference, which can leads to the pressure difference, and the warm
air will raise, the cool will rush into the space. It is a hard thing for
us to locate the wind distribution, because there are many factors
affect it, including geographic factors. However we can identify the
three major wind belts in the world, they lie in doldrums ,
30°latitude ,and polar front .Using wing energy to generate
electricity is a good way; it can not only meet the electricity demand,
but also can reduce the pollution. So, many countries are actively
developing the wind market ,and by the end of 2004, the total
installed capacity is almost 48,000 MW, and Europe is leaders
accounting for 72﹪ . In the wind market, there are 8- 10 primary
countries which have the big share, they are Demark, Germany, India,
Italy, Netherlands, Spain, the United Kingdom, and the United
States.
China is a country with rich wind, it has being developed in recent
years, and by the end of 2005 the total installations had reached 1260
MW. Although it has some problems, we should be optimistic about
its future.
                            Wind Energy
                        Environmental aspects
                         Renewable energy course
                        Supervisor: Prof. Göran Wall
                               Yilong Zheng
                                 Sep. 2006




1.   Renewable energy
     Renewable energy technology and products have great global market
     demands, especially wind and solar power. In the developing countries
     with considerable quantity of population, there are many peoples living in
     remote villages or isolated islands are not able to access electricity.
     Providing electricity service is on the top list of most developing countries.
     These technologies are having been proved mutual in rural electrification.
     It is a highly appreciated way transferring such technologies and
     localization of production to low the production cost, and it also will
     benefit both enterprise itself and beneficiary population, especially in
     poverty alleviation.

2.   Energy payback period for wind turbines

     Although wind energy systems involve a significant initial investment, they
     can be competitive with conventional energy sources. The length of the
     payback period – the time before the savings resulting from your system
     equal the cost of the system itself – depends on the system you choose, the
     wind resource on your site, electricity costs in your area, and how to use
     your wind system. wind power is commercially less viable than
     conventional power, despite being environmentally and socially more
               desirable. Compared to conventional power, which variable costs are very
               high . In capital investment, wind power has a higher share. In financial
               terms, wind power would be a slightly more expensive source of power than
               other conventional and 'green options'. In addition, the uncertainty of wind
               resources and insufficient data impose risks on the investor. Total power
               generation in any year depends on the prevailing wind speeds, which is the
               factor that beyond the investor’s control. Despite having a short gestation
               period, wind power projects have long payback periods compared to
               conventional power, which imposes a risk on the investor again .



          3. Birds
          Windrower’s environment-friendly technology makes it an attractive renewable energy
          resource. However, wind power projects can be hazardous to wildlife. Birds and bats are
          killed or injured when they collide with windrowers and blades. Windrower project
          construction also may destroy important wildlife habitat or affect wildlife during breeding,
          feeding or migration.
          4. Noise

Virtually everything with moving parts will make some sound, and wind turbines are no exception. Well designed
wind turbines are generally quiet in operation, and compared to the noise of road traffic, trains, aircraft and
construction activities, to name but a few, the noise from wind turbines is very low. Outside the nearest houses,
which are at least 300 meters away, and more often further, the sound of a wind turbine generating electricity is
likely to be about the same level as noise from a flowing stream about 50-100 meters away or the noise of leaves
rustling in a gentle breeze. This is similar to the sound level inside a typical living room with a gas fire switched on,
or the reading room of a library or in an unoccupied, quiet, air-conditioned office.

      Source/Activity       Indicative noise level aB (A)
   Threshold of hearing                   0
Rural night-time background             20-40
       Quiet bedroom                      35
    Wind farm at 350m                   35-45
  Car at 40mph at 100m                    55
    Busy general office                   60
 Truck at 30mph at 100m                   65
   Pneumatic drill at 7m                  95
    Jet aircraft at 250m                 105
     Threshold of pain                   140

Information taken from The Scottish Office, Environment Department, Planning Advice Note,
PAN 45, Annes A: Wind Power, A.27. Renewable Energy Technologies, August 1994

          5.    Wind Turbine Safety
                                                    The components of a wind turbine
are designed to last 20 years. This means that they will have to endure more than
120,000 operating hours, often under stormy weather conditions.
   Compare with other engine, it usually only operates only some 5,000 hours during
its lifetime. Large wind turbines are equipped with a number of safety devices to
ensure safe operation during their lifetime.
Sensors
One of the classical, and most simple safety devices in a wind turbine is the vibration
senso, which was first installed in the Gedser wind turbine. 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.
Rotor Blades
Safety regulations for wind turbines vary between countries. Denmark is the only
country in which the law requires that all new rotor blades are tested both statically,
i.e. applying weights to bend the blade, and dynamically, i.e. testing the blade's ability
to withstand fatigue from repeated bending more than five million times. You may
read more about this on the page on Testing Wind Turbine Rotor Blades.
Overspeed Protection
It is essential that wind turbines stop automatically in case of malfunction of a critical
component. E.g. if the generator overheats or is disconnected from the electrical grid
it will stop braking the rotation of the rotor, and the rotor will start accelerating
rapidly within a matter of seconds.
   In such a case it is essential to have an overspeed protection system. Danish wind
turbines are requited by law to have two independent fail safe brake mechanisms to
stop the turbine.
Aerodynamic Braking System: Tip Brakes
he primary braking system for most modern wind turbines is the aerodynamic braking
 stem, which essentially consists in turning the rotor blades about 90 degrees along
eir longitudinal axis (in the case of a pitch controlled turbine or an active stall
ontrolled turbine ), or in turning the rotor blade tips 90 degrees (in the case of a stall
ontrolled turbine ).
    These systems are usually spring operated, in order to work even in case of
 electrical power failure, and they are automatically activated if the hydraulic system
 in the turbine loses pressure. The hydraulic system in the turbine is used turn the
 blades or blade tips back in place once the dangerous situation is over.
    Experience has proved that aerodynamic braking systems are extremely safe.
    They will stop the turbine in a matter of a couple of rotations, at the most. In
 addition, they offer a very gentle way of braking the turbine without any major stress,
 tear and wear on the tower and the machinery.
    The normal way of stopping a modern turbine (for any reason) is therefore to use
 the aerodynamic braking system.
 Mechanical Braking System
                                 The mechanical brake is used as a backup system for
                                 the aerodynamic braking system, and as a parking
                                 brake, once the turbine is stopped in the case of a stall
                                 controlled turbine.
                                    Pitch controlled turbines rarely need to activate the
 mechanical brake (except for maintenance work), as the rotor cannot move very much
 once the rotor blades

         6. Environmental Barriers

 Generally, the environmental impact from a wind project that typically receives the
 most concern like birds colliding with wind turbines. However, some perspective is
 useful here—avian fatalities occur much more significantly from other
 commonly-accepted human-related activities, when compared to wind power. For
 example, it is estimated that roughly 2 billion birds die each year from house cats,
 colliding with buildings/plate glass, vehicles, and communication towers, plus other
 means, as shown on the graph below.

 Nevertheless, birds accidentally collide with wind turbines (as well as, other objects).
 Specifically, the number of avian mortalities in Altamont Pass, California can be
 presented in two ways: (1) avian mortality per wind turbine or (2) avian mortality per
 megawatt. As shown in the graph below, avian mortality per wind turbine in Altamont
 Pass is substantially less than other wind projects. However, the average of the range
 of estimated raptor mortality per wind turbine in Altamont Pass is about 6 times
 higher than other wind projects, apparently due to the unique climate, topography, and
 food sources (such as ground squirrels) that foster raptors. Further, if a comparison of
 avian mortality was presented on a per megawatt basis, avian mortality estimates in
 Altamont Pass would range from the same as other wind projects (which occur at
about three avian mortalities per megawatt per year) to 2.7 times more that of other
wind projects.
Further, avian collisions with
other wind projects are
common—it’s not just an
Altamont issue, and not just a
wind      power     issue    as
mentioned previously. For
example,         see        the
graph—Avian Mortalities per
Wind         Turbine         by
Project—showing            that
Altamont        Pass      avian
collisions per wind turbine are
relatively low compared with
other wind projects across the
nation (as reported by the Government Accounting Office, September 2005).

Beginning in 1988, in order to address avian collisions with wind turbines, and in
coordination with the U.S. Fish & Wildlife Service and/or other agencies, the project
owners in Altamont Pass have conducted and/or been involved with numerous studies
and implemented avian mitigation plans and procedures, including:

conducted/participated/cooperated in avian research studies in Altamont Pass
tested perch guards/platform screens on wind turbines tested electrical shock barriers
on wind turbines installed
nacelle screens on wind
turbines to prevent nesting

   in coordination with Boise
State University's Rator
Research Center, conducted
avian flight experiments of
raptor visual capacities
involving rock doves and
trained Red-tailed hawks
around large and small
turbines
   conducted video monitoring
of select turbines in the field
to try and understand the                       Click Graph to Enlarge
circumstamces surrounding avian collisions
    experimented with painting patterns on wind turbines blades to increase visibility
    experimented with bird flight testing, involving homing pigeons, to test potential
collision flight paths across Altamont Pass
     tested avian path obstruction structures particpated in Alameda County's rodent
control (prey management) program implemented power line anti-electrocution
modifications turning off certain turbines during nesting season when active nests are
found tracking and documenting avian injury and mortality under the Wildlife
Response & Reporting System
In addition, in coordination with the U.S. Fish & Wildlife Service and other agencies,
we are continuing our avian study efforts and developing additional adaptive
management plans for the purpose of reducing avian collisions, including:

     seasonal shutdown of all wind turbines, up to 3 1/2 months per year permanent
relocation and/or shutdown of the highest risk turbines, up to 4% continued
retrofitting of power poles to prevent bird electrocutions plus additional mitigation
measures implementation of a scientific monitoring program formation of a scientific
review committee to help assess the most effective methods to reduce avian collisions
commitment to repowering in the future, beginning in 2009, which is expected to
reduce avian collisions

It is anticipated that these latest avian adaptive management plans will cost the
Altamont Pass wind farm owners roughly $9 million per year or over $110 million
over the next 13 years--the most money ever committed in the world dedicated to save
birds in a wind power application. However, since we’re producing less renewable
energy, please recognize that we’re reducing bird impacts, but conversely, increasing
human health problems, that is, more fossil-fired power increases deaths and heart
attacks (see discussion above) — a decision made by local permitting officials.

Finally, wind energy is one of the cleanest, most environmentally friendly energy
sources in the world. Wind energy development protects air quality, reduces the
effects of global climate change, and displaces mining and drilling for natural gas,
coal, and other fuels. Wind energy is one of the least harmful energy options to
animals and humans. By offsetting the impacts from other energy sources, the use of
wind energy improves environmental conditions for humans, as well as, birds and
other wildlife.

With respect to concerns about avian impacts from wind power, the choice is not
wind or nothing—our society demands a large and steadily growing supply of
electricity. If that electricity does not come from wind, it will come from some other
source with almost certain more damaging environmental consequences. The question
we must all ask ourselves is: if not wind, then what? [source: AWEA]

For more information about the environmental, health, and economic benefits of wind
power, please visit our
References



1.   Scottish Office, Environment Department, Planning Advice Note
2.   EPA’s Design for the Environment Program
3.   Environment for Development http://grid2.cr.usgs.gov/greatlakes/
4.   The Introduction of Wind Turbine Safety Rules http://www.bwea.com/


                                                        Conclusion
    The mostly energy sources are from oil coal or nucleus. The question of oil crisis has become a world question,
but the coal will bring pollution that restricts the application of the coal. In recent two years, the price of oil has
become expensive that affects the world economic. Wind power is the renewable energy that can prevent the
pollution of the environment, and it must benefit for the environment.
Wind Energy - Economical Aspects
       Renewable energy course
      Supervisor: Prof. Göran Wall
               Yulu Mao




               Sep. 2006
Abstract
A wind turbine is the machine for converting the kinetic energy in wind into
mechanical energy. This topic gives a brief introduction of the situation of wind
turbine developing in countries both developing and developed included. And the
main wind turbine manufactories in world are also mentioned.
But which interests me is the wind turbine components developing situations and how
to supply more efficient on designing.


Words:   wind turbine, grid, component, BEM theory
Contents

Abstract..........................................................................................................................................25
Contents .........................................................................................................................................26
1. Introduction...............................................................................................................................27
2. Relationship between Frequency and Voltage ........................................................................29
3. Generation with Wind turbine.................................................................................................31
     3.1 Off-grid wind turbines.......................................................................................................31
     3. 2 the grid wind turbines ......................................................................................................33
4. Technical situation and main manufactories in the world.....................................................35
     4.1 Technical situation and installed capacity .........................................................................35
     4.2. The manufactory of wind turbine.....................................................................................36
5. The components of Wind Turbine and Basic Thesis ..............................................................39
     5.1 Blade .................................................................................................................................39
           5.1.1 Blade introduction..................................................................................................39
           5.1.2 Blade element theory..............................................................................................40
     5.2 Breaking System ...............................................................................................................42
     5.3 Others................................................................................................................................43
REFERENCES..............................................................................................................................46
1. Introduction
Wind energy utilization has increased in the past 10 years, in 2002 alone; the
utilization number of global market grew by more than 30%.

The biggest five countries are Germany, USA, Spain, Denmark and India, with over
1,000 MW of wind generating capacity (figure below). We could find a greatly
increase from 1995 to the end of 2002, the installed capacity of wind power plants
worldwide has grown from some 5,000 MW to over 31,000 MW. The potency of
wind energy is much greater, and it is supposed that the total installed wind generating
capacity will reach approximately 90,000 MW by 2010, and 60,000 MW of which
will be in Europe. [1]




                Figure 1: Global Leaders in Wind Energy, 2002 [1]
The mechanical energy is used directly by machinery, such as a pump or grinding
stones, the machine is usually called a windmill. If the mechanical energy is then
converted to electricity, the machine is called a wind generator.


                    It may be the oldest type of tools which convert the wind power
                    to the mechanical power. But it maybe more like a toy for kids
                    than a tool. When people blow to the face of windmill, the wind
                    will make the blades rotate.



                    The windmill   which we could find in
                    most of the     countries, as Holland,
Denmark ect. We could still         remember this scene:
SANCHO-QUIJOTE holding a           spear rushes at a big
windmill on the old horse.



Denmark is the country which leads wind power technology in the world. There is
more      than  20%    Danish
electricity of consumption is
supplied by wind power. There
is almost half of the wind
turbines produced all over the
world by Danish turbine
manufacturers.




It is reported from the China
Meteorological Administration (CMA) that, china will construct 10 big wind power
stations in the 15 years. In the 2020, installed capacity of wind power in China will be
2000 KW. There has been 14 wind power stations in Xinjiang, Inner Mongolia
Guangdong, Fujian, Zhejiang, etc. 260 power generations has been installed, the
installed capacity is over 5.7×104 kW.
But there still are some problems: In one hand, China has not the technique of making
the key components of wind turbines, in the other hand; the management of
constructing wind power station is lack of scientific techniques and standards.

England: It is reported by AJPLUS: Energy Saving House which was designed by
Hamilton Officer is examined and approved by Southwark committee. The whole
building will have 3 wind turbines with 9-diameter blades. It could supply the
electricity for light of the whole building
        2. Relationship between Frequency and Voltage

        From the figure by measure from a island wind farm in one windy night, it indicated
        that more frequently change in wind speed causes the voltage, which is generated
        from wind turbine, more decrease from ideal designed capacity of generate electricity.

Figure 2: Voltage variations and power output from the wind turbine during one night. [2]




   Svenska Hogarna rated power of 21 KW
                                                    Andros’s wind farm rated total power of 15MW
        The reason is: there is a small rang of speed of wind could be used by wind turbine,
        approx from 10~25 m/s. The utilization curve shows below.




                           Figure 3: Available wind power. Power from a
                    stall-regulated turbine and power from a pitch-regulated
                                            turbine. [2]


        This Figure indicated that:

        1. Even if there is huge wind power on some of areas, calculated in the ‘wind
        resource’, but it hardly transfers to electricity.
2. Choose a suitable wind turbine for locals is practical and realistic. Or there will be a
waste and low efficiency.
3. Speedy wind turbine's design can help a lot on wind resources utilization.
3. Generation with Wind turbine
3.1 Off-grid wind turbines
Using wind turbines without connection to the grid (off-grid), it is widely used for a
small application, housing light and charging a battery, etc. With a small wind turbine
and a certain wind speed, it could supply the convenient electricity power (a few kW
to around 10kW [3]). It is also good for rural electrification, telecom, and other
off-grid applications. The most obvious advantages of wind turbine of off-grid are
easy to construct maintenance and remove. These advantages make it able to be used
on the sea-ships, single houses and other buildings which are far from the main power
supply grid to fulfill the daily power need.
Smart wind turbine may be convenient for the small house to meet the daily energy
consumptions.
On the contrary, there would be a problem under some circumstances. For example,
there are 4 situations, we analyze these respectively with the number from 1 to 4
below.

                                  Wind
              Consumption                      Yes              No

                        Yes                      1               2
                        No                       3               4
                                Table 1: Choice situations

Obviously, the only situation [1, 4] could be the ideal situation; also we assume that
the energy which is transferred by the smart wind turbine could fulfill the need of the
house’s energy consumption.
How about Situation2? Unlikely, there is not wind or wind is unable to transfer
enough energy for house’s consumption.
There would be 2 solutions: looking for a supply of energy (or close the door of the
house to go to sleep or leave the house before the wind turbine supply energy again):
The people in the house could use a battery for the supply, and continue his work.
How long the energy could last depends on the capacity of the battery. But we know a
battery would charge a high price for a high capacity of electric storage. But obviously,
it is not good for long term. We must find a solution.
So, the solution for the problem, it is widely used to connect smart wind turbine to
grid to supply a gap. When there is enough energy from smart turbine, there would be
no need for electricity from main grid. When it is not enough, the house could use the
energy from grid for supplement. On the contrary, it could also transmit extra
electricity from smart turbine to the main grid.
But there may be some technical problem between main grid
and smart wind turbine, but it has a bright fortune.


Example 1: Off-grid wind turbine:

The New Micro-Wind Turbine
In the optimum conditions, the wind turbine which is made by Wern Micro-turbine,
could generate as much as 40KwH per month of electricity. It could be used widely to
charge the battery banks at 12 or 24 Volts DC, or use of others.


                      A service for battery charge is tested on the taxi of Japan
                      through a special wind turbine which set on top of the taxi. It
                      may solve the problem that people usually are affected by low
                      power of cell phones. [4]
3. 2 the grid wind turbines

If the wind development is grid connected, it is probable that the turbines will have a
capacity in the range of 50-500kW or perhaps higher- some developments now use
turbines with capacities of 1.3 MW or greater. [5]
Electricity which is generated by wind tends to be more valuable to the electrical grid
systems than if it were produced at a random level. The main problems at grid
disturbance are risks of over currents in the generators and the converter, and
exceeding voltage in the DC-link. [6] A poor grid of wind turbine will has greatly
influence on the quality of power. Esp.: the grid short circuit power and the X/R and
ratio of the grid.

Grid connected turbines must be connected to two power resources, one for power
control, and the other for power supply. The power which is used for controlling the
turbine is through start-up, operation of the wind turbine. The wind turbine starts to
generate power at a cut-in speed, for example around 4 m/s [5] for many modern
turbines. An excitation current is taken from the grid and used to keep the wind
generator in phase. This means that if the grid is out of action the wind turbine cannot
produce any power. During operation, electrical energy produced from the wind
turbine is fed directly into the electric utility grid.

Grid-connected developments also need 2 point factors: Abundant wind resource and
hence financial return on the sale of electricity.
To build a good wind farm in abundant wind resource, could not just need the big
turbines, which have the capacity of supply MW electricity. There are so many factors
affects the quality of the grid of wind power. For example: the location of the wind
turbine, the ways of connecting the turbines in a grid, and inter-connections of grid,
also, the material of wind turbine will be a factor. E.g.: A wind farm is a development
consisting of a cluster of several wind turbines often installed in rows, which are
perpendicular to the wind direction. Building a road will also be needed, it is not only
just for maintain the wind turbines, but also could be used for farming. Such wind
farms may use wind turbines with a generation capacity ranging from around 200kW
up to 1.5MW [5] or even higher. This type of system is becoming more and more
common to meet individual European countries targets to cut greenhouse.
To connect the grid network, how about the strength of the grid, whether it could
afford the power from the wind turbines and how much power the grid could afford,
must be considered. It is also one of the points before designing the wind turbine farm.
Besides the admission by the authorities would be a factor influent the designing of
wind turbine.
Grid connection costs will depend on the location and strength of the grid. If the grid
needs to be strengthened the capital cost will likely be high and could be prohibitive.
Regulations for connecting to the grid will vary from country to country therefore
contact the local network operator for details. [5]

For Turbine must be distant 7 times of length of the turbine’s blade from each
other, So a long blade also means a wider area of wind farm.
4. Technical situation and main manufactories in the world

4.1 Technical situation and installed capacity

The objects of improving the technical of turbine are to reduce the cost, increase the
efficiency of converting the wind power to the other powers, for example electricity,
and others, and make the energy supply convenient and safe.
At the present time, we use the Wind Partnerships for Advanced Component
Technology (Wind PACT) to lower the cost of designing and testing improvement the
components. And by these methods, we could get to know the potential barriers and
find a way to solve them. Working together of the whole industry could help us to
have a high speed of improving the technology of wind turbine.

To meet the energy need of our whole nations everywhere, it may be not easy.
Distributed Small Wind Systems may solve this problem at a certain extent. For the
contribution of distributed small wind systems, the rural areas which are far from the
energy supply system and rich of the wind power could fulfils the need of energy by
this method.

Besides, the horizontal axis wind turbine (HAWT) and vertical axis wind turbine
(VAWT) designs are used for wind turbine designing, which is also very efficient.
HAWT based on the theories of an aerodynamic model implementing the blade
element theory and evolutionary algorithm. The wind turbine designing software
become more and more powerful and more and more user-friendly the software
environments become. It makes an easy way to reduce the wind turbines’ cost, have
more durable, also more efficient.

The average size of a wind
turbine rose from 300 to             r       W
                                    P i ce/ K H
600 kW , the trend of               45
                                    40              40
developing is bigger and
                                    35
bigger. It is supposed that         30
the percentage of wind              25
power generated electricity         20
will increase from less than        15
1% at present to 20% in 50          10
years. By the increasing             5                          4               3
capacity of wind turbine             0
the     price      of    per                    1980         2000         2007-2010
Kilowatt-hour          have
decreased       from      40      Figure 4: The trend of price per kilowatt-hour [45]
cents/kWh in 1980 to 4 cents/kWh in 2000. The object of in 2007 to 2010 is
decreasing to 3 cent per kilowatt-hour.

The LM 61.5 P is the world’s longest wind turbine
blade, developed by LM Glasfiber in close
collaboration with REpower Systems – the German
manufacturer of the biggest wind turbine in the world.
These blades were a major challenge in every respect,
  and our engineers were able to expand the envelope for which is possible in blade
  production. In conjunction with developing the world’s longest blades, LM Glasfiber
  focused strongly on material selections. Our consistent strategy is to identify the best
  material for each tiny component of the large blade without incurring unnecessary
  extra costs. Using the somewhat more expensive carbon fibre is an example of this.
  Our engineers decided to integrate carbon fibre in a completely new way in some key
  areas. This actually kept the use of carbon fibre to the minimum by combining the
  best qualities of both materials. [7]

  SUPERTURBINE(TM), which is produced by the
  Slsam Off-Shore, could be a huge wind turbine but
  with many advantages. In one hand, it need not
  gear-box to shift the wind power to a certain speed,
  the generator directly is driven by the wind power.
  As a result, the most costly component could be
  eliminated, and the weight could be decreased either,
  the moveable could be increased. On the other hand,
  flotation near the surface forms a fulcrum, with the
  weight of the rotors and driveshaft balanced by a
  downward force from mooring below. As a result, It is combined with the wind
  force to define the projecting angle of the shaft. The rotors can be staggered, spiral,
  or in line. [8]



  According to the photos below, we could see that the Windside Wind Turbine is a
  vertical wind turbine. The turbine rotor is rotated by two spiral-formed vanes, based
  on sailing engineering principles. These differences are needed for use in different
  conditions. They are also designed without gears, thus it is much suitable to use on
  the sailing and have some of the advantages of Super-turbines.




  4.2. The manufactory of wind turbine

  There are the main capacities of wind turbines in the world with their manufactories.

Manufactories of Wind                                                                              Research about
                                                  Wind Turbine Service
     Turbine1                                                                                       Windturbine




  1
      Generally, most of manufactories not only product the turbine, but also do researches on the components.
•   ABB Ltd.
•   Airtricity
                               •   Det Norske Veritas
•   Ecotècnia sccl -
                                   Certification of wind turbines
•   Enercon GmbH,
                                   and wind turbine projects.
•   Eoltec
                               •   Hansen Transmissions Int.
•   Gamesa Corporacion                                                   •  EMD A/S
                                   Gear Units for Wind Turbines
    Tecnologica                                                            WindPRO
                               •   Natural Power
•   Hush Turbine                                                           software package
                                   International wind energy
•   LM Glasfiber A/S                                                       for project design
                                   consultancy services
•   PB Power                                                               and planning of
                               •   Pauwels Trafo Ireland
•   REpower                                                                turbines
                                   recently     celebrated    the
•   Selsam Innovations /                                                 • Garrad Hassan
                                   unveiling of the 200,000th
    Superturbine Inc.                                                       and     Partners
                                   transformer
•   Southwest Windpower                                                     Ltd.
                               •   Valmont Wind Energy, Inc.
•   Suzlon Energy Ltd
                                   the Valmont wind turbine is 4
•   Vergnet
                                   times       durable       than
•   Vestas
                                   non-galvanized tower.
•   Wind Prospect
•   Windside
•   WinWinD Oy




                Table 2: Main manufactories with their research areas.
                                           Wind Turbine Sizes     max Size      min Size
                                                                    (KW)         (KW)
                        ABB [10]                           250          5250
                       Airtricity [11]                     200            660
       Generators Productors
                    Ecotecnia Sccl [12]                     0.1            75
                  ENERCON GmbH [13]                        900            900
                        eoltec [14]                           6           250
                    Gamesa Eolica [15]                     850          2000
                      PB Power [16]                        200            750
                  Suzlon Energy Ltd [17]                   350          2000
                SouthwestWindpower [18]                    250            500
                       vergnet [19]                        250          5000
                        Vestas [20]                        850          4500
                     Wind Prospect [7]                     225          2000
Table 3: The Range of Generators in the Main Wind Turbine Manufactories of World




                               Wind Prospect [20]


                                      Vestas [19]


                                     vergnet [18]

                SouthwestW indpower
                       [17]

                Suzlon Energy Ltd [16]


                                    B ower [15]
                                   P P


                                am
                               G esa Eolica [14]


                                       eoltec [13]


                           N R O   m
                          E E C N G bH [12]


                               Ecotecnia Sccl [11]


                                     Airtricity [10]


                                            B
                                          AB [9]


                                                       0   2000   4000   6000    8000   10000   12000




Figure 5: The Range of Generators in the Main Wind Turbine Manufactories of World
5. The components of Wind Turbine and Basic Thesis


5.1 Blade

5.1.1 Blade introduction [6, 9]

Although there are so many kinds of wind turbine, and the number is increasing, the
elements of wind turbine are the difference of wind speed between blade sides. With
differences of wind speeds between blade sides, it causes a pressure to force blades to
continue revolving. (it will be discussed later)
There are 3 kinds of material of blades have being used: Wood, Glass fiber
Reinforced Plastic (GRP), Carbon Fiber Reinforce Plastic (CFRP). There into,
because of high expense, CFRP is not used for wind turbine widely.
It is most common used number of blades from 1 to 3. For the advantages and
shortages of ones is analyzed in the table below.

Number of             Advantages                        Shortage
 Blades
One       One blade wind turbine have a best May need a counterbalance
          cost of construction and potential and therefore it is not lighter
          reductions in maintenance costs.   than 2 blades one.
                        2
Two       Get more 6% efficiency compared
          with one blade wind turbine. [xx]
Three              Get     more     2-3%     efficiency More cost of potential
                   compared with two blades wind reductions in fabrication and
                   turbine.                               maintenance costs.
                   Have a aesthetic.
             Table 4: The advantages and shortages with different number of blades




2
    All efficiency be got on the tip blade speed at 60-70m/s.
5.1.2 Blade element theory [27]

The blade element theory generally used for aero elastic time calculation in based on the Blade
element momentum theory (BEM). The Blade Element Momentum (BEM) Theory is an efficient
and basic way to give good accuracy with respect to time cost.

As shown in the Figure [6]:

Vrel – relative speed
D – Drag force
L – Lift force, which perpendicular to the Vrel.

                             ρc
                    D=       2
                          Vrel C D
                        2
                       ρc 2
                    L=    Vvel C L
                       2

CD, CL – Drag and Lift airfoil coefficients
(generally given as function of angle of
incidence).
c – Blade cord length

So, it is easy to get the D, L.
                                                       Figure [6] : The local forces on the blade.
Then, we discuss the FT, FN.                           [28]

                FN = L cos φ + D sin φ
              FT = L sin φ − D cos φ
       φ = α + θ ( α >15o .the blade will stall)

                                      (1 − a )U ∞
              For:       tan φ =
                                      (1 + a ' )ωγ

a and a ’ uncertain, so we calculate them as follow:

                                  1
                  a=
                              sin 2 φ
                         4            +1
                             σC N + 1
                                 1
                  a' =
                           sin φ cos φ
                         4             −1
                              σCT                            Figure [7]: Velocities at the rotor plane.

                     C N = C L cos φ + C D sin φ
        In which:
                     CT = C L sin φ − C D cos φ
σ - The annular area of blade covered (certain by blade length)
So, we could get the normal force (T) and the torque (Q) on the control volume of thickness dr, is
since FN and FT are forces per length.
                                1   U ∞ (1 − a ) 2
                                      2
                   dT = NFN dr = ρN                cC N dr
                                2     sin 2 φ
                                    1   U 2 (1 − a)ωr (1 + a' )
                   dQ = rNFT dr =     ρN ∞                      cCT rdr
                                    2         sin φ cos φ

All necessary equations have now been derived for the BEM model, we could use computer to
simulate in different radius of blades.
5.2 Breaking System
Wind turbine needs to rotate in a certain speed in order to keep generating steady voltage
electricity. It is indicated in Figure [8], To Prevent from burning down the generator by high speed,
and limits the rotating speed in a range receivable. It is necessary to use braking system.
There are two type of brake systems defined by the material of braking components:

1: Aerodynamic Brake




                 Figure 8: Aerodynamic brake by: http://www.windpower.org/

The aerodynamic braking system now installed on most modern wind turbines for the
primary braking system. There are 2 methods to decelerate the rotation through
increasing the area of facing-wind to increase friction and decelerate the rotation. By
turning the rotor blades about 90 degrees along their longitudinal axis or in turning the
rotor blade tips 90 degrees for the case of a stall controlled turbine.
If the dangerous situation is over, the aerodynamic brake on the blades or blade tips
return.
They are also safe, efficient and, which is the most important, no damage on the
components of turbine.

2: Mechanical Brake




                                 Figure 9: Mechanical Brake

The mechanical brake is used as a backup system for the aerodynamic braking system,
and to stop the rotation for maintenance work completely.
The disc is made of special material which must be used in much high temperature,
700 centigrade approximately.



       Type of Braking System                   Merits and Validity
                                   Less stress be placed on the work components
         Aerodynamic Brake         Use to limit speed of rotation
                                   No damage on the components
                                   Complete stop the rotation
         Mechanical Brake
                                   Use for fixing on gear failure
       Table 5: The merits and validity with aerodynamic and mechanical brake
5.3 Others

        Controller
  The controller supervises the status of wind turbine ceaselessly to prevent from
  occurring to any problem when the wind turbine working include overheat of
  gearbox and generator. The controller can stop the wind turbine’s rotating and
  inform the operator of the turbine.

       Generators
  Usually be called
  inductive generator
  or       asynchronous
  generator.        The
  modern       generator
  usually     has    the
  capacity            of
  electricity     power
  output from 500 KW
  to 1500KW.


       Rotor
  The blades and the
  hub together are
  called the rotor.

       Gear box:                   Figure 10: The main components of wind turbine
  The gears box can
  shaft and increase the rotational speed from about 30 to 60rpm to about 1200 to
  1500rpm. It is much important, without the gears box, we could only use 1000rpm
  to 3000rpm of generator with 2, 4 or 6 electrodes for connecting the 50Hz AC
  electricity directly. There would be more than 2 times of velocity of sound on the
  endmost of the blades. Maybe we could make an AC generator with a lot of
  electrodes. But it will cost much, and has a much weight.
  So with the gears box, we could have a lower torque and a higher speed.
  To the 600KW or 750KW turbine, the scale of gears is 1:50 approximately.
  Anemometer and Wind vane: Measures the wind speed and transmits wind
  speed data to the controller. Measures wind direction and communicate with the
  yaw drive to orient the turbine properly with respect to the wind.

      Yaw drive
  yaw drive make the wind turbine face to the wind.

       Tower
  Tower is for holding the turbine at a high place. For the higher the location is, the
  higher speed the wind is. The modern 600KW turbine’s tower is from 40m to 60m.
  The shape would be a pipe or grid; it depends on the cost of construction of wind
  turbine. The pipe tower will cost more, but safer for the operator.
Figure 11: The process of generation of wind turbine
Conclusion
1. Wind power generation as a renewable energy will have a broader developing area
in the future.

2. The frequency of voltage not only depends on the energy of wind which is
extracted by the blade, but also depends on the frequency of wind speed.

3. An even more capacity of wind farm could make the frequency of voltage more
stabilization.

4. Wind turbine with grid will make the housing electricity supply more efficiency.

5. Three blades wind turbine is widely used in the wind power generation and have a
good balance between efficiency and cost of investment. But it still needs to consider
the fact when choice the different types of wind turbines.

6. The one of the most problem in wind generation is how to utilize the wind energy
in an excess wind speed condition. It is also the trend of wind turbine research.
REFERENCES
1. <Renewable Energy Projects Handbook>, by World Energy Council, 2004
2. <Grid Interaction and Power Quality Wind Turbine Generator Systems>, by Ake
    Larsson, 1997
3. http://www.windpedia.org/
4. http://www.autohome.com.cn/
5. <Wind Energy>, by ENERGIE, 2001
6. <A review of wind energy technologies>, by G.M. Joselin Herberta, S. Iniyanb,
    E.Sreevalsanc, S. Rajapandiand, 2005
7. http://www.windprospect.com/
8. http://www.selsam.com/
9. http://zhidao.baidu.com
10. http://www.abb.com/
11. http://www.airtricity.com
12. http://www.eco-web.com/register/00606.html
13. http://www.enercon.de
14. http://www.eoltec.com
15. http://www.gamesa.es
16. http://www.pbpower.net/
17. http://www.suzlon.com/
18. http://www.southwestwindpower.com
19. http://www.vergnet.fr/Accueil.php
20. http://www.vestas.com/uk/Products/
21. http://www.cma.gov.cn
22. http://www.scandinavica.com/
23. http://www.hushenergy.com.au/
24. http://www.eco-web.com
25. http://www.energyenv.co.uk
26. http://www.nrel.gov/
27. <Aero elastic Simulation of Wind Turbine Dynamics>, by A. Ahlstrom, 2005
28. <Basic Rotor Aerodynamics applied to Wind Turbines.>, by O. L. Hansen and D.
    J. Laino, 1998
            Wind Energy
Economical Aspects & Project Development
  With Real Best Practice Projects Data
             Renewable energy course
           Supervisor: Prof. Göran Wall
              Shahriar Ghahremanian



                   Oct. 2006
Abstract

In the economical aspects of wind energy, obviously energy production cost must be separated
from energy produced value. This section deals with wind energy production cost. Data for costs
are related to wind turbines connected to grid and with power 100 kWe to 300 kWe. Nowadays
this kind of turbines are most cost effective than smaller or bigger ones. Total energy production
cost of a wind turbine system depends on the below items:
     1. total investment cost
     2. effective life time of system
     3. operation and maintenance cost
     4. physical properties of wind and wind turbine output energy
     5. technical availability
Details of above mentioned aspects will be discussed and production cost per kilowatt hour as a
function of wind regime will be evaluated.

For any wind turbine installation, there are additional activities:
    1. construction of foundations an access roads
    2. electrical connections
    3. site erection
    4. project development and management

So the most important and the first thing are project development and management. Wind farm
development may be divided to number of phases:
      1. initial site selection
      2. project feasibility study
      3. planning application
      4. construction
      5. operation

At last in appendix B, a very good data gathering from 9 real wind energy case studies by RET
Screen software from many countries is illustrated.
Table of contents

Introduction
1- Economical Aspects
  1-1 Total investment cost
  1-2 Effective life time of system
  1-3 Operation / Maintenance Cost
  1-4 Physical properties of wind and wind turbine output energy
  1-5 Technical availability
  1-6 Total Production cost
  1-7 Cost Comparison with Other Energy Sources
2- Project Development
  2-1 Initial site selection
  2-2 project feasibility assessment
  2-3 the measure-correlate-predict technique
  2-4 site investigation
  2-5 Public investigation
  2-6 Preparation and submission of planning application
Appendix-A: Sample Wind Farm Costs
Appendix-B: 9 Wind Energy Project Analyses
References
Introduction
Wind energy is the most rapidly expanding source of
energy in the world today. Over the past decade, the
world-wide installed capacity of wind energy has grown
at an average rate of over 28% per year, leading to an
installed nameplate capacity at the end of 2002 of over
31,000 MW — enough to power 7.5 million average
American homes or 16 million average European homes.
As of January, 2003, Germany was the world leader in
wind energy installations, with 12,001 MW installed,
followed by Spain (4830); the U.S. (4685); Denmark
(2880); India (1702); Italy (785); the Netherlands (688);
the U.K. (552); China (468); and Japan (415). Although
wind power only supplies about 0.4% of the world’s electricity demand today, the size
of that contribution is growing rapidly. In Germany, the contribution of wind power to
electricity consumption is over 5%, and in Denmark it is approximately 25%. The
cost to generate wind energy has decreased dramatically from about $0.38 per
kilowatt-hour (kWh) in the early 1980s to the $0.03 to $0.06/kWh range in 2003, and
it continues to decrease.

1- Economical Aspects
As previously mentioned, wind energy is said to be the
fastest growing renewable energy in the world. Almost
40,000 MW of wind turbines were installed at the end
of 2003 in more than 50 different countries. The growth
of wind energy is impressive, especially in Europe
where about 28,000 MW of wind power is installed.
Growing indeed, but is the wind industry able to
support itself economically? If it is not, should the state
subsidise it to allow it to continue its growth? In this
regard, we try here to demonstrate that wind energy is
economically sustainable if it fulfils one of the two
following conditions. First, it should be cost
competitive compared to conventional energy sources.
If it were, this would be an important incentive to
develop it further so that it can reach its full potential
on the energy market. Second, in the case where wind
energy is not cost competitive and needs to be
subsidised to compete in the market, it must be
profitable for the society to promote it. Indeed, the
investment of state’s funds to promote the wind
industry has to bring gains to the society in return,
financial, social, or environmental ones.
1-1 Total investment cost
Total investment of wind turbine is divided to turbine manufacturing (ex-work),
construction like foundation, building and engineering and connecting to grid.
As reported by USA and the Netherlands approximately %75 of total investment is
related to turbine.

        Region             Power kWe      Turbine cost US$ per kWe
    United states[1]           200                1000 - 1200
European community[2]        100 - 400           1000 – 1300
  The Netherlands[3]           250                    800

So we can conclude that the total investment is about 900 – 1300 US$ per kWe. But
the experience in US shows that this cost can be decreased. Probably making the
turbine should be more cost effective than construction but connecting to grid are
increasing.

1-2 Effective life time of system
For economic considering, wind turbines often have 20 years economic life time and
this time is equal to system design. Although we should notice that the best turbines
have proven life time around 10 to 15 years.

1-3 Operation / Maintenance Cost
O & M costs are often considering as a percentage of total investment or electricity
production cost per kilowatt hour.
              Region                   O & M Cost US cent/kWh
 Europe ( scientific experiences)[2]               0.5
    European community study                        1
US department of energy & SERI[1]                   1
                                          0.6 (for first 2 years)
 Danish energy agency (1990) [3]         0.8 (for next 3 years)
                                            1 (after 5 years)

According to statistical surveys done by Risø National Laboratory using a model for
annual operation and maintenance costs, the percentage of the total investment
attributed to operation and maintenance costs rises as wind turbines become older
(Danish Energy Agency, 1999, p.19). Operation and maintenance costs are divided
into parts such as services, consumables, repair, insurance, administration, lease of
site (Danish Energy Agency, 1999, p.19).

Annual operational and maintenance costs in % of the investment in the wind turbine
(Danish Energy Agency, 1999, p.19)

Machine Size    Year 1-2   Year 3-5    Year 6-10   Year 11-15   Year 16-20
  150 kW          1.2        2.8          3.3         6.1          7.0
  300 kW          1.0        2.2          2.6         4.0          5.0
500-600 kW        1.0        1.9          2.2         3.5          4.5
1-4 Physical properties of wind and wind turbine output energy
Generally for simple comparison, output energy of wind turbine systems express
yearly. Average output energy per square meter of rotor swept per year is the below
form:
                              E = b(v 3 )      KWh/m2/yr
b: Efficiency Coefficient (this factor is an efficiency quality of wind turbines, is not
constant around the world and depends on average velocity of wind in a year and
wind distribution)
v: velocity average in a year

                            Efficiency Factor

    4
  3.5
    3
  2.5
    2
  1.5
    1
  0.5
    0
        1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991
                                       Year

Pic 4-1: improvement of efficiency factor of wind turbines [4]
This figure shows that technology development has increased the efficiency and under
Western Europe wind conditions, the maximum efficiency factor reached to 3.5.




Pic 4-2: Distribution function of wind velocity
This figure illustrates that many differences in wind conditions exist around the earth
and suitable locations should be considered precisely.
         1-5 Technical availability
         System availability is the portion of year that turbine can produce energy. A turbine
         may not produce energy all the year because of maintenance, unpredictable events and
         repairing.
         There are no records or reported experiences about unavailability. Only US (as figure
         5-1) showed that medium sized wind turbines (250 KWe) probably reached to desired
         availability and large scale wind turbines (> 300 KWe) are in first steps. The best
         wind turbines in US reaches to %95 availability level after 5 years operation.

                                   Technical Avaiability %


           120
           100

            80
            60
            40

            20
             0
                 1981   1982    1983     1984     1985    1986    1987     1988    1989
                                                  Year


         Fig. 5-1 Technical availability of best US wind turbines [5]

         1-6 Total Production cost
         Some studies have been done to reach the general characteristics of total production
         cost and here this is summary of them presented. SERI/DOE considered the large
         turbines and got information from local energy producers [3]. Data of EC based on
         the recent wind turbines installed in Europe [1, 2]. Denmark information is for 250
         KWe wind turbine [3].
                                        SERI / DOE [3]            EC [1,2]               DEA [3]
                                          400 – 500 US$/m2 =              400 – 600 US$/m2 =        5680 DKK/KWe =
     Total investment cost               1000 – 1200 US$/KWe             900 – 1100 US$/KWe            770 US$/KWe
   Average of wind velocity              6.6 m/s in 25 m height                    -               6.5 m/s in 30 m height
 Total gained energy per year             800 – 1070 KWe / m2                      -                   1000 KWe / m2
        Capacity factor                             -                           % 28.5                     % 22.3
          Availability                            % 95                           %95                          -
       Total energy loss                          % 23                             -                          -
                                                                                                    1 - 2 years : % 1.4
                                                                         % 2 of total investment
            O&M                                 1 cent / KWh
                                                                                per year
                                                                                                     3 – 5 years : % 2
                                                                                                    6 – 20 years : % 2.5
  Substitution cost of turbines               27000 – 40000 $
                                                                                    -                        -
     (after 8th & 20th yrs)            ( for 200 KWe wind turbine)
            Lifetime                              30 yrs                         20 yrs                   20 yrs
          Interest rate                           0.061                            -                         -
         Fixed cost rate                          0.102                            -                         -
Investment (real) rate of return                     -                        % 5 per year              % 7 per year
           Total Cost                        6.8 US cent/KWh             3.5 – 7 US cent/KWh         4.5 US cent/KWh
A lot of items can be discussed about this study. For example in EC capacity factor
almost considered high and in US long lifetime. Generally Danish study seems more
realistic. As a result, we can conclude total production cost is about 5 – 10 US cent /
KWh.

In general, the initial investment for a 1MW wind turbine project is about 1.1 million
EUR (S.E.I., 2004, p.4). As shown in the below table, the most expensive part of the
investment is the construction costs of the turbines themselves, accounting for 80 %
of the total installation cost [5].

Average cost of a typical 600 kW turbine project (Danish Energy Agency, 1999)

Component                 Average DKK   (600kW)
Turbine ex-works5         3 146 000
Foundation                149 000
Grid connection           288 000
Electrical Installation   20 000
Tele communication        14 000
Land                      103 000
Roads                     39 000
Consulting                36 000
Finance                   20 000
Insurance                 94 000
Total                     3 909 000


1-7 Cost Comparison with Other Energy Sources

Since the 1980s, the cost of wind energy decreased by approximately 90% and is
expected to continue to lower down with the constant growth of the industry
(A.W.E.A., 2002, p.1). Data from 1996 comparing the levelized (Include all capital,
fuel, and operating and maintenance costs associated with the plant over its lifetime
and divides that total cost by the estimated output in kWh over the lifetime of the
plant). Cost of wind energy to that of other energy sources are shown in below table.
It should be noticed that wind power, without the addition of subsidies, has a cost
level situated in the same range than conventional energy sources, such as coal or gas.
According to the same data, nuclear power appears to be much less competitive.
Furthermore, it has to be mentioned that the gas price has increased since that time to
reach 15 to 20 USD cents/kWh, while wind energy cost slightly decreased. (A.W.E.A.,
2004, p.1)
Levelized cost of different
energy sources Fuel Levelized
cost (1996) (USD cents/kWh)
Coal       4,8 - 5,5
Gas        3,9 - 4,4
Hydro      5,1 - 11,3
Biomass    5,8 - 11,6
Nuclear    11,1 - 14,5
Wind       4,0 - 6,0
However, Risø National Laboratory presents a different scenario. According to it,
wind power production costs are situated around 4 EUR cents/kWh, where coal and
natural gas would respectively cost around 3 and 3.8 EUR cents/kWh. (Morthorst,
2004, p.11) Another cost assessment done by the Belgian Ministry of Energy and
Sustainable Development (Pauwels and Streydio, 2000, p.18) also conclude that wind
energy is not fully cost competitive. It compared wind electricity production
onshore/inland, onshore/on coast, and offshore (Calculations were done considering
working times of 1800, 2600, and 3250 hours, respectively, the turbines functioning at
20% of their nominal value the rest of the time. The estimated depreciation rate is 5%
per year for 20 years of activity) to conventional fuels. The first column of below
table presents the basic production costs, demonstrating that even onshore/on coast
production in Belgium is not price competitive compared to coal, gas and nuclear
power.

Production, external and total costs of different energy fuels (Pauwel and Streydio,
2000, p.18).

                              Production cost         External cost           Total cost
          Fuels
                               ( EUR cents)           ( EUR cents)          ( EUR cents)
        Nuclear                    3.1                     0.1                   3.2
       Gas (CHP)                   3.2                     1.0                   4.2
         Coal                      3.4                     2.4                   5.8
  Wind onshore/inland              7.8                     0.3                   8.1
  Wind onshore/on coast            4.5                     0.1                   4.6
     Wind offshore                 5.8                     0.1                   5.9



Therefore, it appears that in the majority of the presented scenarios, wind energy
cannot compete in the market with traditional energy sources without the help of
financial support. Except in the A.W.E.A. data, wind energy is not price competitive
at the moment.
2- Project Development

The development of a wind farm has very similar process
to any other power generation project, but it requires that
wind turbines must be located in high wind speed sites to
maximize energy production. A turbines size makes visual
effect that is very important to environmental impact.
Three main elements of the wind farm project development
are identified as:
    1. technical and commercial issues
    2. environmentally considerations
    3. consultation
The dialogue and consultation process with local inhabitants and planning authorities
will guide to project success on environmental considerations. Technical and
commercial considerations are often straightforward.


2-1 Initial site selection

A study is carried out to locate a suitable site and as a potential for location of a wind
farm. The mean power production for a wind turbine is given by:

                                E = T ∫ P (U ) f (U ) dU
P (U): power curve of wind turbine
f (U): probability density function of the wind speed
T: time period

The power curve is available from turbine suppliers while an estimate of probability
density function may be obtained from wind atlas (European wind atlas, 1989). At this
stage of the project development only an approximate of the wind farm output is
required in order to confirm the potential of the site. However it will be useful to
supplement the wind atlas with an initial computer modelling.
If measured site wind speed data is available then energy yield of a wind turbine can
be estimated as shown in below figure by combining the wind speed distribution with
the power curve:
                                         i =n
                                   E = ∑ H (u i ) P (u i )
                                         i =1
H (ui): number of hours in wind speed
P (ui): power output at the wind speed

In addition to assessing the wind resource it is also necessary to confirm that road
access is available for transporting the turbines and other related equipment. Blades of
large wind turbines can be made up to 40m in length and so clearly can pose
difficulties for transport on minor roads. For a large wind farm, the heaviest piece of
equipment is main transformer if a substation is located at the site.
The initial technical assessment will be accompanied by a review of the main
environmental considerations. The most important constraints includes special
consideration of areas designated as being of value and ensuring that no turbine is
located so close to domestic dwellings that will cause e.g. noise, visual domination or
light shadow flicker. A preliminary assessment of visual effects is also required
considering the visibility of the wind farm particularly from important public
viewpoints. If there are areas of particular ecological value, then these need to be
avoided as well as any locations of particular archaeological or historical interest.
Communication systems like micro wave link, TV, radar or radio may be affected by
wind turbines and this needs to be considered at an early stage.
In parallel with the technical and environmental assessments it is normal to open
discussion with local civic or planning authorities to identify and agree the major
potential issues.


2-2 project feasibility assessment

Once a potential site has been identified then more detailed, and expensive,
investigations are required in order to confirm the feasibility of project. The wind
farm energy output, and the financial viability of the scheme, will be very sensitive to
the wind speed over the life of the project.
To establish a prediction of the long term wind resource, it is recommended to use the
measure-correlate-predict (MCP) technique. (Derrick, 1993, Mortimer, 1994)


2-3 the measure-correlate-predict technique

The MCP approach is based on taking a series of measurement of wind speed at the
wind farm site and correlating them with simultaneous wind speed measurements
made at a meteorological station. The average period of site-measured data is chosen
to be the same as that of the meteorological station data. In its simplest
implementation, linear regression is used to establish a relationship between the
measured site wind speed and long term meteorological wind speed data of the form:

                                  Usite = a + b Ulong-term

Coefficients are calculated for 12 30˚ directional sectors and the correction for the site
applied to the long term data record of meteorological station. This allows the long
term wind speed record to be used to estimate what the wind speed at the wind farm
site would have been over the last 20 years. This estimates which is used as a
prediction of the wind speed during the life of the project. Thus, MCP requires the
installation of cup anemometers and wind vane at the wind farm site. And if possible
one anemometer is mounted at the hub height of the proposed wind turbines with
others lower to allow wind shear to be measured. Measurements are made over at
least 6 month period and correlated with measurements made concurrently at the
meteorological station.

Difficulties:
    1. with modern wind turbines, high site meteorological masts are necessary also
       with planning permission
    2. availability of suitable meteorological station within 50-100 km
    3. the gaps and quality of meteorological station
2-4 site investigation

At the same time as wind speed data are being collected
more detailed investigations of the proposed site may
also be undertaken. These include:
    • A careful assessment of existing land use
    • How best the wind farm may be integrated with
        e.g. agricultural operations
    • The ground conditions for ensuring turbine foundations, access roads and
        construction areas
    • Local ground conditions for position of turbines
    • Hydrological study for determining whether spring water supplies of wind
        farm
    • More detailed investigation like bend radii, width, gradient and any weigh
        restrictions on approach roads
    • Discussion with local electricity utility concerning the connection to
        distribution network

The planning application requires the preparation of writing an environmental
statement and the scope of this generally agreed with civic authorities during project
feasibility assessment.



2-5 Public investigation
Prior the erection of the site anemometer the wind farm developer may initiate some
form of informal public consultation like local community organizations,
environmental societies and wildlife trusts.


2-6 Preparation and submission of planning application

Although environmental impacts is significant but the preparation of environmental
statement is an expensive and time consuming and requires the assistance of various
specialists. The purpose of wind farm environmental statement may be summarized:

   1.   physical characteristics of wind turbines and their land use requirement
   2.   environmental character of proposed site and surrounding area
   3.   environmental impacts of the wind farm
   4.   measures which mitigate any adverse impact
   5.   need for the wind farm and allowance for planning authority and general
        public decision on the application
Topics covered in environmental statement will typically include the following
(BWEA, 1994)

       policy framework
       site selection
       designated areas
       visual and landscape assessment
       noise assessment
       ecological assessment
       archaeological and historical assessment
       hydrological assessment
       interference with telecommunication systems
       aircraft safety
       safety
       traffic management and construction
       electrical connection
       economic effects on the local economy
       decommissioning
       mitigating measures
       non-technical summary
Appendix-A: Sample Wind Farm Costs

Capital cost are often quoted in "per
installed kW" and therefore depend on
the method used to rate the machine.

In a report from Redding Management
"Potential for Australian Capacity to
expand to meet the target –
Commonwealth Government’s
mandatory 2% renewable target",
January 1999, they suggested that a
better figure would be based on the
blade swept area which allows costs to
be compared with the annual energy production.

For example an indicative capital cost for a "turn-key" contract to supply, install and
commission a large wind farm, as shown in the table, based on 400 kW wind turbines
(and UK experience), is about A$850 - $1,050 per square meter of rotor swept area or
A$1.8 - $2.7 million per MW.

Project Initiation   Financing                              1% project cost

                     Planning Consent                       $10,000 to $50,000

                     Project development/ management        $50,000

Capital Costs        Ex-factory cost of machines            $550/sq.m swept area

                     Install and commission                 15% ex-factory cost

                     Infrastructure & connect               45% ex factory cost

Annual costs         Operation and maintenance              1.5% of capital cost

                     Metering                               0.64 c/kVArh

                     reactive power                         0.5% of capital cost

                     Insurance                              1.5% of gross revenue

                     Land rental Rates                      $13 per installed kW


The turbines, blades and other systems components represent about 60% to 70% of the total
project costs.
Appendix-B: 9 Wind Energy Project Analyses                                        (Data from Renewable Energy Technology Screen case studies, Canada), [11]

                                                    Remote         Wind farm        Green Power    Grid-Connected     Large Wind      Offshore       Isolated Island    Wind Power on       Grid-Connected
            Project name                  Unit
                                                   Community       Repowering        Production      Wind farm         Turbines       Wind farm        Community       Hydro Central-Grid    Wind Farm
                                                     Yukon,          Alberta,         Alberta,     Andhra Pradesh,   Niedersachsen,   Copenhagen,    Newfoundland,         Kennewick,           Wigton,
          Project location                 ---
                                                     Canada          Canada           Canada           India           Germany         Denmark          Canada                WA                Jamaica
    Annual average wind speed             m/s           6              6.5              6.2              6.2              6.4             7.2              6.5                6.6                 8.3
              Grid type                    ---     Isolated-grid   Central-grid     Central-grid     Central-grid     Central-grid    Central-grid    Isolated-grid       Central-grid        Central-grid
        Number of turbines                 ---          1              32                1               80                6              20               6                  49                  23
        Wind plant capacity               kW           150           19200              600            20000             9900           40000             390                63700              20700
   Unadjusted energy production           MWh          585           65375             1933            43022             18848          110599            908               181128              82133
   Pressure adjustment coefficient         ---         0.84            0.9              0.9             0.93               1               1              0.98                0.96               0.89
 Temperature adjustment coefficient        ---         1.08           1.03              1.03            0.96             1.02            1.02             1.04                1.03               0.98
      Gross energy production             MWh          530           60603             1792            38410             19225          112811            926               179100              71637
         Losses coefficient                ---         0.88           0.94              0.95             0.9              0.9            0.89             0.87                0.9                0.77
    Renewable energy delivered            MWh          469           57044             1704            34679             17372          99839             562               161842              55235
    Renewable energy delivered             GJ         1687           205360            6134            124845            62540          359422            2022              582630              198846
   Base case GHG emission factor        tCO2/MWh      0.472           0.513            0.491            0.559            0.861           0.898           0.925               0.559               1.019
Net annual GHG emission reduction         tCO2         210           25772              770            17045             13767          82513             494                79547              47044
            Initial Costs
                    Feasibility Study      %            5              0.1              2.9              0.3              0.5             1.3              2.4                0.3                  0
                    Development            %           4.6             0.2              4.5              0.8              3.5             4.1              4                  1.1                  0
                    Engineering            %           6.9             0.2              4.5              0.6              0.3              0               7.2                0.8                11.3
                    Energy Equipment       %           38.4           81.6              63.9            77.5             69.4            49.8             50.6                74.6               69.6
                    Balance of Plant       %           36.5           12.2              16.3            11.8             21.5            41.7              30                 12.1               10.1
                    Miscellaneous          %           8.5             5.7              7.9              9.1              4.8             3.1              5.7                11.1                 9
                    Feasibility Study      $         4 3,500         1 9,100          3 5,300          47413             36487          548804           30,000             245,200                -
                    Development            $         4 0,000         5 4,700          5 4,900          132604           281631         1735190           50,000             835,500                -
                    Engineering            $         5 9,800         5 9,300          5 4,600          112578            24334             -             90,000             610,500            195,000
                    Energy Equipment       $         331,750       2 4,250,400        7 82,200        13607274         5539156         21064398         632,040            59,275,016          1,206,192
                    Balance of Plant       $         315,000       3 ,635,000         2 00,000        2071877          1716806         17626301         375,000            9,638,000           175,500
                    Miscellaneous          $         73,576        1 ,702,904         9 6,437         1595178           386016         1299375           71,211            8,829,119           156,093
         Initial Costs - Total             $         863,626       29,721,404        1,223,437        17566925         7984431         42274068        1,248,251           79,433,335          1,732,785
     O&M Annual Costs - Total              $         26,074          81968             47662           319831             230             725            22.071            2,557,215            50,050
          Simple Payback                   yr          41.6           11.4              13.8             6.3              7.4             7.3              7.2                11.3                 7
     Year-to-positive cash flow            yr      more than 25       20.1              15.6             7.6              6.8             7.1              6.9             immediate              5.4
     Annual Life Cycle Savings             $          69489          464025            2 ,012         1220962           253446         1472728            2861             1,229,164            37,231
      Benefit-Cost (B-C) ratio             ---         1.15           0.47              1.04            3.18             1.45            1.34             0.98                 -                 1.34
       Avoided cost of energy            $/kWh         0.1            0.06              0.08           0.0901            0.075           0.046            0.19               0.0439             0.0033
References



     1. J.M. Cohen , Methodology for computing wind turbine cost, American energy
         association , 1989
     2. H.N. Nacfaire, Demonstration program for wind energy, United Kingdom, EWEC,
         1999
     3. Danish energy agency: wind energy in Denmark, 1999
     4. N.C. van de Borg, The energy production of wind turbines, The Netherland, 1999
     5. H.J.M Beurskens and E.H.L. Lysen, Perspective of wind energy, European wind
         energy association, 2001, www.ewea.org


     6. British wind energy association, best practice guidelines for wind energy
         development, 2001, www.bwea.com
     7. European wind atlas, Risø national lab, 1999, www.wind-power.dk
     8. International energy agency, wind turbine, 2000, www.iea.org
     9. The wind atlas analysis and application program, www.wasp.dk
     10. D. Taylor, wind energy and the environment, IEEE energy, www.ieee.com
     11. Renewable Energy Technologies Screen International Clean Energy Decision
         Support Centre, www.RETScreen.net
      Wind Energy
And Comparison with other
Renewable energy resources



       Renewable Energy Course
   Supervisor: Prof. Göran Wall




        Setareh janbakhsh
            Oct. 2006
Abstract


Renewable energy sources, or RES, are those energy sources which are not destroyed
when their energy is harnessed. Renewable energy sources are distinct from fossil
fuels, which must be consumed to release energy.

The target of this project is introducing renewable energy and comparison between
them in developed countries and developing countries, including Barriers and Success
factors in wind, biomass, solar, hydro, and geothermal by showing in which countries
is more common. Comparison is figured out energy markets of renewable energies
and Summary of Installed Capacity Costs. Then it is illustrated the Specific Daily
Delivered Electricity and Specific Capital Cost.
Table of contents:



Introduction

       History
       Renewable energy today

1- Leading Renewable Energy Resources

     1-1 Wind energy

     1-2 Biomass energy

     1-3 Geotermal energy

     1-4 Solar energy

     1-5 Hydro energy

2- Resources and Technology Summaries

3- Policies, Economics, Social Considerations and Environment

4- Global leaders in renewable energy resources

5- Resource availability

6- Installed capacity capital cost

7- Operation and maintenance (O&M)

8- Specific daily delivered electricity/specific capital cost

       Daily delivered electricity
       Cost of delivered power

9- Life –cycle cost of energy

10- Environment consideration
Introduction

History

What is now thought of as renewable energy has been exploited by man since his
earliest beginnings. The burning of biomass for heat and light has been practiced
throughout recorded history, not to mention the use of organic foods as energy for
survival. The beginning of the development of wind technology can be dated back to
the late 19th Century and experiments in Denmark. From the 1950s onwards,
photovoltaic (solar) cells saw investment as a result of their usefulness in space craft,
with resulting improvements in the technology and knowledge of materials, along
with reductions in price to levels acceptable to some consumers. The main motivation
for the expansion of renewable energies came with the oil crises of 1973 and 1979-80.
Concern by political leaders in a host of countries saw increases in support for
research and development of new technologies. Wind, wave and solar energy
technologies all benefited from this investment with an increase in the range of their
application.

Renewable energy today

Around 80% of energy requirements in western industrial societies are focused around
heating or cooling buildings and powering the vehicles. However, most uses of
renewable power focus on electricity generation.

Figure 1- World Total Primary Energy Supply, 2002[1]




                                                                   Other includes
                                                                   geothermal, solar,
                                                                   wind, heat, etc.)



Figure 2:2001 products’ shares in OECD renewable energy
Supply , as from IEA (2003).
    1- Leading renewable energy resources[2]

    1-1 Wind Energy

Wind is a widely distributed energy resource.
Between 30ºN and 30ºS, air heated at the equator
rises and is replaced by cooler air coming from
the south and the north. This is the so-called
Hadley circulation. At the earth’s surface this
means that “cool” winds blow towards the
Equator. The air that comes down at 30ºN and
30ºS is very dry and moves eastward, because the
earth’s rotational speed at these latitudes is much
slower than at the Equator. Between 30ºN(S) and
70ºN(S) winds are predominantly western. These
winds form a wavelike circulation, transferring
cold air southward and warm air northward. This
pattern is called Rossby circulation.



Figure3: Global Circulation of Wind over the Earth [3]




Wind energy is today the most rapidly developing renewable energy in the world.
Wind resources will play a larger role in future. There are great expectations for the
future of “offshore technologies”: the installation of turbines with 1.5- 5 MW rated
capacity per unit in wind farms with the total capacity of up to 1,200 MW in coastal
waters. This technology offers a number of advantages: excellent wind conditions
with reduced turbulence at sea, as well as low visual disturbance and noise.
Maintenance and repair of the turbines, however, is more difficult and expensive than
on-shore.
 Although the concept of wind turbines is old, a large-scale development of a new
generation of turbines for power generation only began in the mid-seventies, as a
consequence of the energy crisis of 1973. Technology concepts of modern wind
turbines can be distinguished by two basic characteristics: “power limitation” and
“rotor speed”. The scheme of power limitation can either be active “pitch” or passive
“stall. The rotor speed can be designed as constant or variable. The control of active
and reactive power and the rotation speed is crucial for the operation of the turbines
and their integration into the grid.
1-2 Biomass
Modern biomass is expected to become the renewable
equivalent of fossil fuels of the future. Resources suitable
for energy production cover a wide range of materials.
 (From fire wood which collected in farmlands and natural
woods and forestry crops)
Biomass can be divided into four sub-categories:
              wood
              animal dung
              solid industrial waste
              landfill biogas (it dependent on environmental)
Mainstream Technologies for Biomass
        direct combustion processes
         thermo chemical processes
          biochemical processes
Heat from biomass
Combustion of biomass for steam is used globally: advanced domestic heaters or
district heating, with heat efficiencies of over 70% and with strongly reduced
atmospheric emissions are widely used in Scandinavia, Austria and various Eastern
European countries.

Electricity from biomass
Combustion of biomass for electricity generation is widespread across the world.
Advanced combustion technologies, such as the application of fluidised bed
combustion and advanced gas cleaning allow efficient production of electricity and
heat in Combined Heat and Power installations (CHP). Within the range of about
50-80 MWe , electrical efficiencies of 30-40% are possible today.
Biomass integrated gasification/combined cycle systems (BIG/CC) combine
flexibility of final characteristics with a high electrical efficiency. Electrical
conversion efficiencies up to 40% are possible on a scale of about 30 MWe on the
short term small scale, fixed bed gasifiers coupled to diesel/gas engines (typically for
100-200 kWe systems with an approximate electrical efficiency of 15-25%) are
commercially available on the market.

1-3 Geothermal Energy
Geothermal energy is a renewable and
sustainable energy resource.
Geothermal heat is concentrated in regions
associated with the boundaries of tectonic
plates in the earth’s crust.
On average, the temperature of the earth
increases by about 3ºC for every 100 m in
depth. This means that at a depth of 2 km, the
temperature is about 70ºC, increasing to
100ºC at a depth of 3 km, and so on. However,
in some places, tectonic activity allows hot or
molten rock to approach the earth’s surface, thus creating pockets of higher
temperature resources at easily accessible depths.
Geothermal power generation technologies
There are several types of geothermal energy conversion processes:
    Dry Steam Plants: produce energy for vapour-dominated reservoirs with a typical
      unit capacity of 35 – 120 MWe.
   Flashed Steam Plants: produce energy from liquid-dominated reservoirs which are
     sufficiently hot to flash a large proportion of the liquid to steam. Typical units
     have a capacity of 10 – 55 MWe.
     Binary-Cycle Plants: for low-enthalpy resources binary plants based on the use of
       Organic Rankin Cycles (ORC) are utilised to convert the resource to electricity.
       _ Combined Cycle: the steam first flows through a backpressure steam turbine and
       is then condensed in the organic turbine vaporiser. The condensate and brine are
       used to preheat the organic fluid as in the two-phase binary configuration.
       Geothermal Combined Cycle Plants have electric efficiencies of 10-25%, while
       the capacity factors are frequently above 90%; the plants are independent of
       climate and seasons and can be operated 24 hours a day.

  .1-4 Solar Energy
  Solae heat
    Low-temperature thermal solar energy (LTSE)
  is used to heat water, air or another medium, for
  domestic or professional use. The system
  basically consists of a solar collector, a thermal
  storage and the necessary distribution systems.
     Solar heat pumps are used to convert the energy
  available in solar-heated ambient air into useful
  low temperature heat.
      “Solar architecture” - This passive solar energy
is designed to reduce energy consumption for space heating, lighting, etc. by utilising
the building structure itself for solar energy collection, distribution and storage.
Solar electricity
Photovoltaic (PV) solar energy is the direct conversion of sunlight into electricity
  The solar modules used are a number of solar cells connected in series. The efficiency
  Of practical solar cells is determined by the number of loss mechanisms. The typical
  flat-plate modules achieve efficiencies between 10 – 15%.
  -Solar thermal-electric is used to produce
  high-temperature heat, which is converted into
  electricity. The specific technologies applied are Solar
  Pond Power Plants (SPPP), parabolic trough solar
  power plants, parabolic dish combined with Stirling
  engines and central receiver combined with heliostats.
  The SPPP can achieve an electric efficiency of 10%,
  whereas the dish-Stirling combination can convert
  sunlight into electricity with an efficiency of 30%.


1-5 Hydro Energy
The main civil works of a hydro development are the dam.
The dam directs the water into the powerhouse through
water passages. The powerhouse contains the turbine with
the mechanical and electrical equipment required to
transform the potential and kinetic energy of the water into
electrical energy. Many rivers and streams are well suited
to small hydro-power installations (<10 MWe capacity) and
in large parts of the world there is a need for electric power
in remote areas where these resources are available. New
small hydro developments are usually run-of-river developments .
2- Resources and Technology Summaries [4]

Table 1: Main Characteristics of Different Technologies

                                                   Scale Range,            Efficiency,
Category          Conversion System                                                                   Availability
                                                      MWe                      %

                 Combustion/stand alone             20.0 – 100.0          20–40 (elect.)

                                                                             60–100
                    Combustion/CHP                    0.1 – 10.0
                                                                             (H+P)

                     Co-Combustion                    5.0 – 20.0          30–40 (elect.)

 Biomass            Gasification/Diesel                                                             climate dependent
                                                      0.1 – 1.0           15–25 (elect.)
                         Turbine

                Gasification/Gas Turbine              1.0 – 10.0          25–30 (elect.)

                  Gasification/BIG/CC               30.0 – 100.0          40–55 (elect.)

                 Digestion/Wet Biomass              Up to several         10–15 (elect.)

                                                                                                Highly variable, weather
   Wind           Modern wind turbines                  ~ 5.0                                           dependent
                                                                                                   ( load factor 23%)

                     Dry Steam Plants               35.00 – 120.0

                  Flashed Steam Plants              10.00 –- 55.0
                                                                                             Constant (capacity factor over
Geothermal                                                                10–25 (elect.)
                                                                                                         90%)
                   Binary Cycle Plants              0.25 – 130.0

                 Combined Cycle Plants              10.00 – 130.0

                                                                                                  Hydrology dependent
                       Run-of-River                0.1 - 14,000.0          80-93 (elect)
                                                                                                 (capacity factor 40-90%)
  Hydro
                                                                                                20-90% utilisation factor
                     Reservoir storage             1.0 - 18,000.0          80-93 (elect)
                                                                                                 (peaking and baseload)

                    Photovoltaic (PV)             0.05 – 1.00 kWp         10–15 (elect.)       Daily, , weather dependent

                                                  0.50 – 5.00 kWp

   Solar                                          10 kWp–several
                                                      MWp

                      Thermal SPPP
                                                          <5
                     Parabolic trough
                                                        100.0
                      Dish - Stirling
                                                          5.0


Notes:
     1.    In electrical engineering a load factor is the average power divided by the peak power over a period of time.
     2.    The capacity factor of a power plant is the amount of electricity that it produces over a period of time.
     3.    Gasification is a process that converts carbonaceous materials, such as coal, petroleum or biomass into carbon
           monoxide and hydrogen.
     4.    Digestion is the process of metabolism whereby a biological entity processes a substance, in order to chemically and
           mechanically converts the substance into nutrients.
     5.    Binary is consisting for two parts
    3- Policies, Economics, social considerations and Environment

    Table 2: Technology Specific Barriers and Success Factors [5]

                                                   WIND

                     Barriers                                           Success Factors

-Lack of good wind conditions                          -Sites with sufficient wind-potential
-Uncompetitive technology in the short and             -Political will to introduce subsidies
medium run                                             -decreasing kWh costs from wind by the Kyoto
                                                       protocol

 Developed Countries         Developing Countries      Developed Countries      Developing Countries

- Limited sites onshore     - Lack of financial        - Heavy dependence     -High energy demand
- Unstable production       resources to subsidy       on imported energy     growth rates in
of power                    wind turbine               resources Available    combination with
                                                       offshore sites         shortages of capacity
                                                                              Hybrid solutions suitable
                                                                              for rural electrification

                                                   Biomass
                     Barriers                                           Success Factors

-Dispersed form of energy, variety of                  -Distributed energy production
technological solutions                                -CO2 emissions neutral resource
-Competition from higher value applications            -Reducing fossil fuel imports
- private investors                                    -Private sector involvement in deploying
-Difficulties due to collection and transportation     bioenergy
-Deforestation
-Bioenergy is very land-intensive
-Low load factors increase energy system costs
  Developed Countries         Developing Countries     Developed Countries      Developing Countries

-Perceived depletion of     -Minor influence on        -Distributed energy    -Service to rural
natural resources (wood)    nation’s                   resource               households
-Small-scale resources,     energy supply              -Utilisation of        - Increased production
difficulty in creating      -Not “modern enough”       indigenous energy      capacity in income
economies of scale                                     resources              generating activities,
                                                        -Diversification of
                                                       energy mix

                                                   Hydro

                     Barriers                                           Success Factors

- High upfront investment

 Developed Countries         Developing Countries                Renewable energy source
                                                             No GHG emissions during operation
-Best sites have already    -lack of water resource          Widely distributed around the word
been                        -supply Competition
developed                   for water from other
                            economic sectors
                                             GEOTHERMAL

                      Barriers                                          Success Factors

- Early development and production difficulties        -Quantities of potential geothermal resource.
- Early mismanagement of resource by                   -Some 40 million tones of CO2 emissions can be
overproduction limited the life of the resource (not   saved by doubling geothermal power capacity (of
sustainable)                                           over 8000 MW)
- Drilling technology difficulties                     -Economically viable energy resource; can
(high-temperature environments)                        compete with small thermal or internal
- High up-front investment                             combustion power plants.
-In the past “old” traditional technologies causing
certain environmental problems by direct release
of geothermal steam into the atmosphere or hot
water into rivers and difficulties to use water
dominated resources
 Developed Countries        Developing Countries        Developed Countries          Developing Countries

-Small resources with     -Financing constraints       -Reliable, field proven,    -Over 620 million
minor influence of        due to high up-front costs   -zero pollution energy      people in 39 developing
nation’s energy           -Competition from fossil     resource                    countries could be
                          fuel power plants.           -Significant base-load      100% supplied by
                                                       resource in sites with      geothermal power
                                                       indigenous geothermal
                                                       resources

                                                    SOLAR

                     Barriers                                           Success Factors

-Low energy density                                    -Clean, distributed power solutions
-Resource available only during daytime, sensible      -Thermal electric technologies success for larger
to atmospheric                                         solar stations
and weather fluctuations (influence on low solar       Grants and subsidies for solar energy For Solar
plant factor)                                          Heating
-Costs of solar PV electricity considerably higher     -Vast roof area available
than other renewable sources, high capital costs,      Energy security
long payback periods for Solar Heating
-Few large industrial suppliers
  Developed Countries        Developing Countries      Developed Countries          Developing Countries

-Not cost effective for     -High costs, low           -Low maintenance           -Off grid applications in
grid electrical power       availability of PV         requirements               remote rural areas where
for Solar Heating           electricity For Solar      -High reliability          small amounts of energy
-Volatile production        Heating                    systems For Solar          are required
Necessary integration       -Lack of financial         Heating                    for Solar Heating
in buildings                capability to              -Heavy dependence          -High growth rates in
                            subsidy renewable          on energy sources          combination with
                            energy projects                                       shortage
 4- Global leaders in renewable energy resources

 Table 3: Main Countries with Renewable Energy Resources [6]

                    Biomass              Wind          Geothermal       Solar        Hydro

                 US                                    US
                 Japan                                 Japan                      Canada
                                   Coastal and                        US
                 Germany                               Italy                      Australia
                                   mountainous                        Japan
 Developed       Scandinavia                           Austria                    US
                                   locations –                        Australia
 Countries       Australia                             Germany                    EU
                                   (practically in                    Germany
                 and practically                       Australia                  Scandinavia
                                   all countries                      Italy
                 in                                    Canada                     New Zealand
                 every country                         France

              Brazil               Coastal and
 Developing                                            China
              Russia               mountainous                                    Russia
Countries and                                          India
              and practically      locations –                        India       China
Economies in                                           Mexico
              in                   practically in                                 Europe
 Transition                                            Russia
              each country         all countries



 Figure4: Global Leaders in Wind Energy, 2002[7]
                                                        Figure5: Global Leaders in PV Installed
                                                        Capacity, 2002[7]




 Figure6: Global Leaders in Geothermal Power Generation, 2002[7]
5- Resource availability [8]

The basic four different markets are:
       Off-grid markets in developing countries
        Grid markets in developing countries
         Off-grid markets in developed countries
          Grid markets in developed countries

Off-grid markets in developing countries
The off-grid electricity in remote rural areas can be generated in several ways, both by
fossil-fired power generators (mostly diesel) and by renewable sources. Geothermal
energy, modern biomass or hydro can generate the base load,. Solar and wind sources
are suitable as basic off-grid power resources .
Grid markets in developing countries
Power grids in developing countries are today powered mostly by fossil-fuelled power
plants or by large hydropower. Other renewable sources can play a significant role.
The base load can also be provided by geothermal energy and modern biomass. Their
roles are often defined by resource availability and economical considerations, such as
the distance from grid distribution lines.
Grid markets in developed countries
These markets are already highly developed, and based mostly on fossil fuels, large
hydro and nuclear power. Geothermal, hydro are capable of contributing continuous
energy input to the baseload, while biomass will feed the Intermediate load and solar
and wind the peak load
Off-Grid markets in developed countries
All renewable resources can be deployed, sometimes in multiple utilisations,
combining systems for generation of electricity, heat and refrigeration.



Table 4: Renewable in Energy Markets [9]
                                               Biomass   Wind   Geothermal   Solar   Hydro


                                distant
                              communities        X        X         X         X       X


                  off-grid       in-house
                                                 X        X                   X
                                electricity
   Developed                   stand-alone
   Countries                                                                  X
                                  power

                                base load                           X                 X

                   grid       intermediate
                                                 X
                                  load

                             hybrid systems      X        X         X         X       X

                               cooking and
  Developing                                     X                  X         X
                                 heating
   countries
                  off-grid
                             small base load     X                  X                 X
                                  base load        X                X                X
                    grid
Figure7: Off-grid markets in developed countries [10]
The economic case for renewable has
been improving rapidly over the past
few years. Some renewable energy
technologies are maturing rapidly and
becoming increasingly cost
competitive. For example, wind, hydro,
geothermal power is already
competitive in many wholesale
electricity markets. Other technologies,
such as solar PV, solar water heaters
and biomass are often cost-effective
options to provide services in off-grid
areas in developing countries.
Biomass-fired combined heat and
power (CHP) plants are used in several
European countries; in developed
countries solar powered devices, such
as emergency roadside telephones,
roadside crossing sites, parking meters or traffic lights, can be found in remote as well
as urban areas.
 The following section compares the costs of electricity-generating systems
employing renewable technologies

6- Installed Capacity Capital Cost [11]
The basic starting point for comparison is the installed capacity capital cost. It
includes all planning, design, equipment purchase, and construction and installation
costs for a turnkey plant, ready to operate. In the case of a wind-farm, it would include
the electric power collection system; in a geothermal project the geothermal field
development and geothermal fluids gathering system; the installed capacity capital
data vary due to the resources they are applied to utilize, as well as due to local
variables.

Table 5: Summary of Installed Capacity Costs for Renewable
                                           Installed Capital Cost
                  Category
                                             (US$/kW installed)

        Biomass        Energy crops                 2,900

                           Landfill              900 – 1,000

        Wind               Onshore               900 – 1,200

                           Offshore                 1,600

        Geothermal                              2,000 – 2,500

                   Solar thermal power              2,900
        Solar
                             PV                22,000 – 35,000

        Hydro                                   1,500 – 3,500
Table 6 - Cost of Delivered Power [12]

 Category      Cost of Delivered Power
                      US ¢/kWh

 Biomass                3.0 - 8.5

   Wind                 4.5 – 6.5

Geothermal              3.0 – 8.0

   Solar                  17.0

  Hydro                 2.0 – 8.0


The cost competitiveness of renewable is increasing steadily and is expected to
continue improving in the future, as their market shares grow. Solar energy costs
today can only be acceptable in “niche markets”, where other alternatives are for
some reason unattractive or not feasible. The wind energy industry has made
significant progress in decreasing costs to become economically viable. Large
wind-farms will contribute even more to this trend in the future. Geothermal energy is
already economically viable and can compete in the electricity markets, as is hydro
and some types of biomass (e.g. landfill gas utilisation).

7- Operation and Maintenance O&M

The O&M costs for a modern renewable energy power generating project are
generally low; since the projects are mostly automate.
The O&M cost element includes other routine costs:
       property and other taxes
       land-use payments
       insurance
       transmission access and wheeling fees

Table 7: Typical O&M Ratio [13]
                                                      Category             O&M Ratio

                                          Biomass                         1.0% - 3.0%

                                                            Onshore       2.5% - 4.5%
                                           Wind
                                                            Offshore      3.5% - 5.5%

                                         Geothermal                       2.0% - 3.0%

                                                       solar thermal power 1.0% - 2.5%
                                           Solar
                                                                 PV       1.5% - 2.5%

                                           Hydro                          1.5% - 3.0%
8- Specific daily delivered electricity/specific capital cost

Figure 8: Specific Daily Delivered Electricity/Specific Capital Cost [14]




Table 8: Specific Daily Delivered Electricity/Specific Capital Cost [15]

                                                         Specific Daily
                                                                              Specific Capital Cost
                Category         Plant Load Factor    Delivered Electricity
                                                                                (US$-year/kWh)
                                                       kWh/kW installed

           Energy crops                 75%                   18.0                   0.40
Biomass
              Landfill                  90%                   22.0                   0.12
              Onshore                   25%                    6.0                   0.45
 Wind
              Offshore                  28%                    7.0                   0.62
       Geothermal                       90%                   22.0                   0.28
        Solar thermal power             15%                    4.0                   1.98
 Solar
                 PV                     10%                    2.5                   27.40
               Base-Load               40-90%               10.0-23.0              0.23-0.54
 Hydro
              Peaking Plant            20-60%                4.8-14.4              0.36-1.08

The cost of delivered power is measured in cents per kWh.
 9- Life cycle of energy

Table 9: Typical Payback Time on Investments in Renewable Energy Projects
 (Based on 5% for 20 years)[16]
                Category          Years
                     Onshore       5 - 10
             Wind
                     Offshore     10 - 15
               Geothermal          4 - 10
              Solar thermal       12 - 15
                 Hydro            10 - 30

10 – Environment Consideration
Each renewable energy category has certain environmental disadvantages:
            solar projects require large land areas, the PV industry uses some polluting
       materials, there is an issue of used battery disposal
       wind implies impacts such as visual intrusion, noise, bird mortality and
        telecommunications interference
        geothermal unless used in binary closed cycles with fluid reinjection –
       includes small quantities of dissolved gases including H2S and CO2 and
       problems with disposal of used concentrated brines
         biomass may negatively influence local bio-diversity and environment
          small hydro may have low impact on streams.

 Table 10:CO2 Emissions from Different Power Generating Technologies [17]
                     CO2 emissions at various energy production stages (tonnes per GWh)
                                                             Fuel
Technologies                                              Extraction     Construction   Operation   Total
Conventional coal-fired plant                                  1               1          962        964
Fluidized Bed Combustion plant                                 1               1          961        963
Integrated Gasification Combined Cycle plant                   1               1          748        751
Oil-fired plant                                                -               -          726        726
Gas-fired plant                                                -               -          484        484
Ocean thermal energy conversion                               N/a              4          300        304
Geothermal steam plant                                        <1               1           56        57
Small hydropower                                              N/a             10           N/a       10
Boiling water reactor (Nuclear power plant)                   -2               1            5         8
Wind energy                                                   N/a              7           N/a        7
Photovoltaic                                                  N/a              5           N/a        5
Large hydropower                                              N/a              4                      4
Solar thermal                                                 N/a              3           N/a        3
Wood (sustainable harvest)                                   1509              3          1346       160

Resource Exploration Risks
Renewable resources comprise different resource exploration connected risks:
      - Biomass energy is dependent on uncertain delivery of energy resources,
          which can be influenced by alternative utilisation
      - Wind energy is intermittent, highly dependent on climate and weather
          conditions
      - Geothermal energy resource must be identified, its sustainability may be
          influenced by reservoir degradation, well scaling, pressure drops
      - Solar energy is highly dependent on weather conditions
      - Hydro is dependent on water inputs, highly dependent on climatic
          conditions.
   References

   [1]-IEA/OECD Statistics 2002
   [2]- Renewable energy projects handbook
   [3]- New Renewable Energy Resources, WEC 1994
   [4]- WEC Committee on Renewable
   [5]- www.worldenergy.org & WEC Committee on Renewable
   [6]-Survey of Energy Resources, WEC 2004
   [7] Survey of Energy Resources, WEC 2002
   [8] www.worldenergy.org
   [9] WEC Committee on Renewable
   [10] Bitsch, R, Intelligent Decentralized Energy Supply, COSSP, May-June 2002
   [11] 1. Landfill Gas, the Case for Renewable Energy, CDC, 1998
           2. Wind Energy Costs, National Wind Coordinating Committee
           3. ORMAT Data
           4. BP Projects in the Philippines, 2002
           5. New Renewable Energy, Kan Energy AS, Norwegian Developments, 1998
[12] WEC Committee on Renewable
   [13]
   1- Based on EU data – Scientific and Technological References, Energy Technology
   Indicators, 2002
   2- ORMAT
   [14] The Case for Renewable Energy in Emerging Markets, W-J van Wijk, CDC,
   ORMAT
   [15] WEC Committee on Renewable
   [16] www.worldenergy.org
   [17] WEC Committee on Renewable

				
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