2. Introduction
-
- Course Contents & Day-wise Schedule
3. Course Objective
- The course objective is to ensure learning on fundamentals of
Wind Power Generation
- Upon completion of this training one will be able to identify,
distinguish and apply principles of Wind Power Generation.
4. Methodology
- Trainer-led classroom lectures giving individual attention and
encouraging one- to-one and group discussions
- MS-PowerPoint presentation slides to handle teaching &
learning processes efficiently and effectively
- Workbook containing tests and exercises to stimulate cognitive
capabilities for effective learning
- Familiarising Wind Power related keywords and acronyms
5. Day-wise Schedule
-
- Orientation to Power & Energy
-
- Conventional V/s Non-conventional Energy Sources
-
- Power Production from Wind
6. Day-wise Schedule
-
- Basic Components of Wind Energy Conversion System
-
- Aerodynamic Principles of Wind Turbines
-
- Performance of Wind Turbines
7. Day-wise Schedule
-
- Wind data & Energy Estimation
-
- Wind Energy Site Selection Consideration
-
- Wind Energy, Power Generation Data
8. Recalling the Fundamentals
-
- Rate of doing work(Work done / Time taken)
-
- Independent of thetotal work to be done
-
- Electrical power is usually measured in watt (W), kilowatt
(kW), megawatt (MW)
-
- Capacity of doing work (at certain Rate) (Power x
Duration)
-
- Energy can neither be created nor consumed nor destroyed
-
- Energy, however may be converted or transferred to different
forms
-
- 1 kWh (kilowatt hour) = 3,600,000 Joule
9. Energy
- Everything what happens around is the expression of flow of
energy in one of its forms
- Energy is an important input in all sectors of any country's
economy
- Present Energy Crisis scenario
-
- Standard of living is increasing
10. Energy
- Per Capita energy consumption per annum
- USA with 7% of world's population consumes 32% of the total
energy consumed in the world.
- India with 20% of world's population consumes 1% of total
energy consumed in the world.
11. Energy
- Developing countries like India at present export primary
products such as food,coffee, tea, jute and ores etc.
- This does not give them the full value of their resources
- To get better Value, the primary products should be processed
to products for export
12. Growth of Energy Requirement
- Energy Required (x 10 8Tonnes Eq. Of Coal)
13. Sources of Energy
- Primary Sources of energy
- Secondary Sources of energy
-
- Coal Oil Natural Gas Nuclear (Uranium)
-
- Solar Energy Wind Energy Tidal Energy
14. Commercial / Conventional Energy Sources
- Agricultural & Organic wastes
Source: www.eia.doe.gov 0.3% Waste 1.2% Dung 8% 6.6% Wood 2.0%
Hydro 0.13% Uranium 92% 19.0% Gas 38.5% Oil 32.5% Coal Total Energy
Consumption Source 15. Non-commercial /Non-conventional Energy
Sources
16. Non-commercial /Non-conventional Energy Sources Several
multiple megawatt wind turbines are in operation and many more are
in construction. There are number of small wind turbines and wind
Pumps in use. Electricity Mechanical Energy(Pumping Transport) Wind
The kinetic energy Millions of solar water heaters and solar
cookers are in use.Solar cells and Power Towers are in operation.
Low temperature heat (Space heating water heating and electricity)
Solar Total solar radiation absorbed by the earth and its
atmosphere is 3.8 x 10 24 J/Yr. Comment From / Application Resource
17. Non-commercial /Non-conventional Energy Sources There are
million of biogas plants in operation, most of them are in China.
Bio-gas (Cooking, mechanical power etc.) The worlds standing
bio-mass has a energy content of about 1.5X10 22J Biomass
(principally wood accounts for about 15% of the worlds (commercial
fuel) Consumption; It provides over 80% of the energy needs of many
developing countries.High temperature heat (Cooking, Smelting)
Biomass Total solar radiation absorbed by plants is 1.3X10 21J/Yr
Comment From / Application Resource 18. Non-commercial
/Non-conventional Energy Sources Installed capacity Is more than
2500 MW but output is expected to Increase more than seven fold by
2000. Electricity The total amount of heat stored in water or steam
to a depth of 10 km is estimated to be 4 X 10 21J that stored In
the First 10 km of dry rock Is around 10 27J/yr Geothermal energy
supplies about 5350 MW of heat for use in bathing principally in
Japan, but also in Hungary Ice land and Italy. More than one lakh
houses are supplied with heat from geothermal wells. The installed
capacity is more than 2650 MW (thermal) Low temperature heat
(Bathing space and water heating) Geothermal The heat flux from the
Earth's interior through the surface is 9.5 X 10 20J/Yr. Comment
From / Application Resource 19. Non-commercial /Non-conventional
Energy Sources The Japanese wave energy research vessel, the
Kaimel. has an Installed capacity of about 1 MW. There are In
addition several hundred waves powered navigational buoys designs
after large prototypeElectricity WaveThe amount of energy stored as
Kinetic Energy in weaves may be of the order of 10 18 JOnly one
large tidal barrage is in operation (In France) and three are small
schemes In Russia and China total Installed.Capacity is about 240
MW and the out put around OS TWh/Yr. In addition China has several
small tidal pumping stations.Electricity TidalEnergy dissipated In
connection with slowing down the rotation of the earth. Comment
From / Application Resource 20. Non-commercial /Non-conventional
Energy Sources Large hydro schemes provide about one quarter of
worlds total electricity supply and more than 40% of the
electricity used in developing counties. The installed capacity is
more than 363GW. The technically usable Potential is estimated to
be 2215GW or 19000 TWh/Yr There are no accurate estimates of the
number of capacity of small hydro-plants currently in operation.
Electricity Hydro The annual precipitation land amounts to about
1.1 x 10 17Kg. of water. Taking the average elevation of land area
as 840 m. The annually accumulated potential energy would be9 x 10
20 J Comment From / Application Resource 21. Economies of Wind
Power Wind Power cost v/s conventional Power Cost Years of
Operation 22. Green Power
- Wind Farm of 1MW capacity saves 200 MT of Coal annually
- Wind Farm of 1MV avoids emission of pollutant gases annually as
under :
-
- Nitrogen dioxide 1 2.4 MT
-
- Carbon dioxide 300 500 MT
-
- Particulate like fly ash 150 280 kgs.
- Average temperature rise of around 1-3.5 0C by year 2100 a rate
of warming greater than at any time over the last 10,000 years
23.
- Energy Content of Fuels GJ per tonne
- LPG (Liquefied Petroleum Gas: Propane, Butane) 46.0
- JP1 (Jet aircraft fuel) 43.5
- Diesel / Light Fuel oil 42.7
- Natural Gas 39.3 per 1000 Nm 3
- Household Waste 1995 10.0
-
-------------------------------------------------------------------------------------------------------------------------------------------------
- CO 2-Emissions kg CO 2per GJ / kg CO 2per kg fuel
- Petrol (Gasoline) 73.0 / 3.20
- Diesel / Light Fuel oil 74.0 / 3.16
- Heavy Fuel Oil 78.0 / 3.15
- Natural Gas (methane) 56.9 / 2.74
- Coal 95.0 / 2.33 (steam coal), 2.52 (other)
Green Power 24. Wind
- Which prime source is responsible for the origin of Wind ?
- Temperature Differences Drive Air circulation
- CoriolisForce Affects Global Winds
- How a Wind turbine taps Wind energy ?
Coriolis Force 25.
- Windresults from Air in motion
- Air in motion arises from a pressure gradient
- Solar radiation heats the air near the equator
- This low-density heated air is buoyed up
- At the surface this air is displaced by cooler more dense
higher-pressure air flowing from poles
- In the upper atmosphere near the equator the air thus tend to
flow back toward the poles and away from the equator.
- The net result is a global convective circulation with surface
winds from north to south in northern hemisphere.
Wind 26. Wind is much more complex due to:
- Earth's rotation causes Coriolis force resulting in
-
- an easterly wind velocity component in the northern
hemisphere
- Boundary layer frictional effects between the moving air and
the earth's rough surface (mountains, trees, buildings and similar
obstructions )
-
- Differential heating of land and water. Unequal solar
absorption and thermal time constants of land and water. During
daylight the land heats up rapidly compared to nearby sea or water
bodies and there tend to be a surface wind flow from the water to
the land. At night the wind reverses, because the land surface
cools faster than the water.
-
- Hills and mountainsides. The air above the slopes heats-up
during the day and cools down at night more rapidly than the air
above the low lands. This causes heated air during the day to rise
along the slopes and relatively cool heavy air to flow down at
night
- 2% of all solar radiation falling on the face of earth is
converted to kinetic energy of wind. 30% of this occurs in lowest
1000m elevation of the atmosphere.
Diurnal (Night and Day) Variations of the Wind 27. Wind Energy
use
- Conversion of kinetic energy of wind into mechanical energy
that can be utilised to perform useful work or to generate
electricity.
- When the wind blows against the vanes or sails they rotate
about the axis and the rotational motion can be made to perform
useful work.
- Because wind turbines produce rotational motion, wind energy is
readily converted to electrical energy by connecting the turbine to
an electric generator.
Wind Turbines Deflect the Wind 28. The power from wind
- Three factors determine for deriving power form wind
- Cross-section of wind swept by rotor
- Conversion efficiency of the rotor, transmission system and
generator
29.
- It is not practical to extract all of the wind's energy because
the wind would have to be brought to a halt and this would prevent
the passage of more air through rotor.
- A 100% efficient aero-generator would therefore only be able to
convert up to a maximum of around 60% of available energy in the
wind into mechanical energy.
- Well-designed blades will typically extract 70% of the
theoretical maximum but losses incurred in conversion mechanism
could decrease overall efficiency to 35% or less.
The power from wind Mean (Average) Power of the Wind 30. Energy
contained in Wind
- Energy available in wind is kinetic energy
- Kinetic energy of any particle is equal to one half of its mass
(M) times the square of its velocity (V) : P a= MV 2
- The amount of air passing in unit time, through an area (A),
with velocity (V) is A*V; and its mass (M) is equal to its volume
multiplied by its density ( ) of air (1.225 kg/m 3at sea level) M =
AV a = AV * V 2 Pa = AV 3Watts Available Wind energy is
proportional to thecubeof thewind speed
31. Energy contained in Wind
- Available wind energy is proportional to thecubeof the
windspeed.
- It is thus evident that a small increase in wind speed can have
a marked effect on the power in the wind.
- Wind power is also proportional to air density (1.225 kg/m 3at
sea level).
- It may vary 10-15% during the year because of pressure and
temperature change.
- It changes negligibly with water contents.
32. Power Production from Wind
- The wind power is proportional to the intercept area. Thus an
aero turbine with a large swept area has higher power than a
smaller area machine.
- Area is normally circular diameter (D) in horizontal axis
machine
- This indicates that the maximum power available from the wind
varies according to the square of the diameter of the wind area or
square of the rotor diameter.
- Thus doubling the diameter of the rotor will resulting a
fourfold increase in the available power
- Wind machines intended for generating substantial amount
ofpower should havelarge rotorsand be located in areas ofhigh wind
speeds.
33. Power Coefficient
- Power coefficient (Cp), describes that fraction of the power in
the wind that may converted by the wind turbine in to mechanical
work
- Cp =Power output from Wind Machine
- It is the fraction of power in a wind stream that can be
extracted.
- It has a theoretical maximum value of : Cp (max)=
0.593(popularly known asBetz coefficient )
34. Power Generatedand wind Speed 35. Wind Turbine Power
- P = 0.5 xx A x Cp x V 3x Ng x Nb
- P = Power in watts (746 watts = 1 hp) (1,000 watts = 1
kilowatt)
- = Air density (about 1.225 kg/m 3at sea level, less higher
up)
- A = Rotor swept area, exposed to the wind (m 2 )
- Cp = Power coefficient (.59 {Betz limit} is the maximum
theoretically possible, .35 for a good design)
- V = Wind speed in meters/sec (20 mph = 9 m/s)
- Ng = Generator efficiency (50% for car alternator, 80% or
possibly more for a permanent magnet genertor or grid-connected
induction generator. Induction generator efficiency is more than
95%)
- Nb = Gearbox/bearings efficiency (depends, could be as high as
95% if good).
36. Cp / Relationship
- Where : Cp = Power coefficient
- Also, = Rotor tip speed / Wind velocity
- Where = Rotational speed of rotor
- V= Wind speed in meters/sec
- Power coefficient of a rotor (Cp) is maximum for a unique Tip
speed ratio ( )
37. Basic Components of a Wind Turbine Aero Turbine Gearing
Coupling Electric Generator Wind Output Power Controller Yaw
Control & Pitch control Wind Speed & Direction Speed Speed
& Torque 38.
- What makes the rotor turn ?
- Stall Controlled Wind Turbines
- Pitch Controlled Wind Turbines
Aerodynamic Principles of Wind Turbines 39. Types of Wind
machines
Savonious Type Downwind Type Darries Type Three Blade Two Blade
40. Characteristics of Wind Machines
- - Complex in complete conversion System
- - Subjected to continuous cyclic gravity loads
- - Structural Support is Critical
- -Can be active for Wind from any direction
41. Forces acting on the Blade
- V T :Wind velocity due to the blade turning
- F T :Torque producing component
- V R :Resultant wind velocity
- F R :Resultant force on the blade
F W F R F T a V T V R Plane of Rotation V 42. Performance of
Wind Machines 43. Yaw Control
- To keep the swept area perpendicular to the predominant Wind
direction
-
- The wind turbine is said to have a yaw error, if the rotor is
not perpendicular to the wind. A yaw error implies that a lower
share of the energy in the wind will be running through the rotor
area.
44. Wind Turbine Towers
- The tower of the wind turbine carries the nacelle and the
rotor.
- Towers for large wind turbines may be either tubular steel
towers, lattice towers, or concrete towers.
- Guyed tubular towers are only used for small wind turbines
(battery charges etc.)
Tubular Tower Lattice Tower Concrete Tower Guyed Tubular Tower
45. Blade & Tower
- To avoid hitting the tower at high wind speeds
1.5 m. gap as per international compliance 5 0tilt Rotor Blades
Lift Direction 46. Choosing between low and tall Towers
- The optimum height of the tower is a function of :
- How much the wind locally varies with the height above ground
level, i.e. the average local terrain roughness (large roughness
makes it more useful with a taller tower)
- The price the turbine owner gets for an additional kilowatt
hour of electricity.
47. Reasons for Choosing Large Turbines
-
- Larger machines are usually able to deliver electricity at a
lower cost than smaller machines.
-
- The reason is that the cost of foundations, road building,
electrical grid connection, plus a number of components in the
turbine (the electronic control system etc.), are somewhat
independent of the size of the machine.
-
- Maintenance Costs are largely independent of the size of the
machine.
- Difficult sites Locations
-
- In areas where it is difficult to find sites for more than a
single turbine, a large turbine with a tall tower uses the existing
wind resource more efficiently.
48. Reasons for Choosing Smaller Turbines
-
- Several smaller machinesspread the riskfailure
-
- Thelocal electrical grid may be too weakto handle the
electricity output from a large machine. This may be the case in
remote parts of the electrical grid with low population density and
little electricity consumption in the area.
-
- Wind fluctuations occur randomly, and therefore tend to cancel
out. Again, smaller machines may be an advantage in a weak
electrical grid.
-
- A large machine really does not attract as much attention as
many small, fast moving rotors.
-
- The cost of using large cranes, and building a road strong
enough to carry the turbine components may make smaller machines
more economic in some areas.
49. Wind Machine Transmission
- To increase greatly the rates of rotor rotation
- Fixed Ratio gears are recommended for top mounted Wind machines
due to their high efficiency, known cost and minimum system
risk
- For ground mounted Wind machines which requires right-angle
drive the transmission cost might be reduced substantially by using
large diameter bearing with ring-gears mounted on the hub
50. Why to use a Gearbox ?
- If we used an ordinary generator, directly connected to a 50 Hz
AC three phase grid with two, four, or six poles, we would have to
have an extremely high speed turbine with between 1000 and 3000
revolutions per minute (rpm).
- With a 43 m. of rotor diameter that would imply a tip speed far
more than twice the speed of sound !!
- Another possibility is to build a slow-moving AC generator with
many poles. But it may need a 200 pole generator to arrive at a
reasonable rotational speed of 30 rpm.
- Another problem is, that the mass of the rotor of the generator
has to be roughly proportional to the amount of torque (moment, or
turning force) it has to handle. So a directly driven generator
will be very heavy (and expensive) in any case.
` 51. Gearbox : Less Torque, More Speed
- The practical solution, which is used in the opposite direction
in lots of industrial machinery, and in connection with car engines
is to use a gearbox.
- With a gearbox you convert between slowly rotating, high torque
power which you get from the wind turbine rotor -and high speed,
low torque power, which you use for the generator.
- The gearbox in a wind turbine does not "change gears". It
normally has a single gear ratio between the rotation of the rotor
and the generator.
- For a 600 or 750 kW machine, the gear ratio is typically
approximately 1 to 50.
52. Choice of Generators and Evacuation
53. Wind Machine Electrical GeneratingSchemes
- Constant Speed frequency (CSCF)
-
- Large Generator Connected to Grid
- Variable Speed constant frequency (VSCF)
-
- Small generators for autonomous application
- Variable Speed variable Frequency (VSVF)
-
- Stand alone power application
54. Wind Machine Electrical GeneratingSystems
- Type of the Load (Battery, Grip, Inverter etc.)
-
- Small Generator ( =< 100 kW )
-
- - Permanent Magnet, DC Generators
-
- Medium Generator ( =< 1000 kW )
-
- - DC Generator, Synchronous Generator,Asynchronous
Generator
-
- Large Generator ( >= 1000 kW )
55. Key Parameters of Wind Turbine Generator
- Machine Availability Hours Number of hours WTG is available
without any breakdown / problem for power generation
- Grid Availability Hours Number of hours state electricity board
common grid is available.
- Export of Power kWh KWh exported to the grid and metered at
Electricity Board (Tri-vector Meter). These units will be billed
for further commercial proceedings.
- Import of Power kWh KWh consumed by WTG components like space
heater, fan, yaw motor, hydraulic pump motor etc. from the
grid.
56. Key Parameters of Wind Turbine Generator
- Export of k VARh Reactive Power supplied to grid e.g. over
compensation.
- Import of kVARh Reactive power drawn from Grid e.g. for
magnetizing current of generator (These units of kVARh charged as
penalty to the owner by State Electricity Board at a rate decided
by respective SEBs)
57. Electrical Generators used in WTGs
- The wind turbine generator converts mechanical energy to
electrical energy.
- Wind turbine generators are a bit unusual, compared to other
generating units you ordinarily find attached to the electrical
grid.
- One reason is that generator has to work with a power source
(the wind turbine rotor) which supplies very fluctuating mechanical
power (torque).
58. Basics of Electrical Power Generation
- Vrms / phase = 2.22 x F x Z x
N S 59. Choice of Generators
- Synchronous Generators Synchronous generators have their own DC
excitation system and hence can work with or without grid
supply
- Asynchronous Generators Induction generators require excitation
power from the grid and hence cannot work without grid supply.
60. Synchronous Generators
- If the magnet is forced around, it is discovered that it sends
alternating current into the STATOR windings.
- It requires more powerful magnet or more stator conductors to
produce much electricity.
- It requires a constant rotational speed in order to produce
alternating current with a constant frequency
61. Synchronous Generators
- The reason why it is called asynchronousGenerator is that the
magnet in the centre will rotate at a constant speed which is
synchronous with (running exactly like the cycle in) the rotation
of the magnetic field.
- Consequently, with this type of generator you will normally
want to use anindirect grid connectionof the generator.
62. Synchronous Generators
- All 3-phase generators use a rotating field.
- The fluctuation in magnetism corresponds exactly to the
fluctuation in voltage of each phase.
- When one phase is at its peak, the other two have the current
running in the opposite direction, at half the voltage.
- Since the timing of current in the three magnets is one third
of a cycle apart, the magnetic field will make one complete
revolution per cycle.
- With a 50 Hz grid, the needle will make 50 revolutions per
second,i.e. 50 times 60 = 3000 rpm (revolutions per minute).
63. Synchronous Generators
- In practice, permanent magnet synchronous generators are not
used very much.
- There are several reasons for this.
-
- One reason is that permanent magnets tend to become
de-magnetized by working in the powerful magnetic fields inside a
generator.
-
- Another reason is that powerful magnets (made of rare earth
metals, e.g.Neodynium) are quite expensive, even if prices have
dropped lately.
- Wind turbines which use synchronous generators normally use
electromagnets in the rotor which are fed by direct current from
the electrical grid.
- Since the grid supplies alternating current, they first have to
convert alternating current to direct 1 current before sending it
into the coil windings around the electromagnets in the rotor.
Grid Connection of Offshore Wind Parks 64. Synchronous
Generators
- If we double the number of magnets in the Rotor, however, we
can ensure that the magnetic field rotates at half the speed.
- This generator has four poles at all times, two South and two
North. Since a four pole generator will only take half a revolution
per cycle, it will obviously make 25 revolutions per second on a
50Hz grid, or 1500 revolutions per minute (rpm).
- When we double the number of poles in the Stator of a
synchronous generator we will have to double the number of magnets
in the Rotor, as you see on the picture. Otherwise the poles will
not match.
65. Asynchronous Generators
- Most wind turbines in the world use a so-called three phase
asynchronous (cage wound) generator
- Also called aninduction generatorto generate alternating
current.
- This type of generator is not widely used outside the wind
turbine industry, and in small hydropower units
66. Asynchronous Generators (Induction Generator)
- It is the rotor that makes the asynchronous generator different
from thesynchronous generator.
- The rotor consists of a number of copper or aluminum bars which
are connected electrically by copper or aluminum end rings, as you
see in the picture to the right.
- The rotor is provided with an "iron" core, using a stack of
thin insulated steel laminations, with holes punched for the
conducting aluminum bars.
- The rotor is placed in the middle of the stator, which in this
case, once again, is a 4- pole stator which is directly connected
to the three phases of theelectrical grid.
67. Asynchronous Generators (Induction Generator)
- When the current is connected, the machine will start turning
like a motor at a speed which is just slightly below the
synchronous speed of the rotating magnetic field from the
stator.
- If we look at the rotor bars from above we have a magnetic
field which moves relative to the rotor. This induces a very strong
current in the rotor bars which offer very little resistance to the
current, since they are short circuited by the end rings.
- The rotor then develops its own magnetic poles, which in turn
become dragged along by the electromagnetic force from the rotating
magnetic field in the stator.
68. Asynchronous Generators (Induction Generator)
- Now, what happens if we manually crank this rotor around at
exactly the synchronous speed of the generator, e.g. 1500 rpm
- Nothing. Since the magnetic field rotates at exactly the same
speed as the rotor, we see no induction phenomena in the rotor, and
it will not interact with the stator.
- But if we increase speed above 1500 in the rotor. The harder
you crank the rotor, the more power will be transferred as an
electromagnetic force to the stator, and in turn converted to
electricity which is fed into the electrical grid.
- The speed of the asynchronous generator will vary with the
turning force (moment, or torque) applied to it. In practice, the
difference between the rotational speed at peak power and at idle
is very small, about 1 per cent. This difference in per cent of
thesynchronous speed , is called the generator's slip.
69. Asynchronous Generators (Induction Generator)
- Thus a 4-pole generator will run idle at 1500 rpm if it is
attached to a grid with a 50 Hz current. If the generator is
producing at its maximum power, it will be running around 1510
rpm
- It is a very useful mechanical property that the generator will
increase or decrease its speed slightly if the torque varies.
70. Asynchronous Generators (Induction Generator)
- Why Induction Generators ?
- The feature of stand alone is not advantageous. Power is not
required in remote areas where normally windmills are installed. It
has to be fed into the grid.
- Induction Generators are :
- Moresuitable for the highly fluctuating power input.
- Simple and rugged in construction (no excitation)
71. Indirect Grid connection of Wind Turbines Rotor, Gearbox,
and Generator VariableDirectIrregularGrid
FrequencyCurrentSwitchedFrequency AC(DC)ACAC 72. Indirect Grid
Connection : Variable Speed
- The advantage of indirect grid connection is that it is
possible to run the wind turbine at variable speed.
- Disadvantages of Indirect Grid Connection is cost . The turbine
will need a rectifier and two inverters, one to control the stator
current, and another to generate the output current.
- Other disadvantages are the energy lost in the AC-DC- AC
conversion process
- The power electronics may introduce harmonic distortion of the
alternating current in the electrical grid, thus reducing power
quality. The problem of harmonic distortion arises because the
filtering process mentioned above is not perfect, and it may leave
some "overtones" (multiples of the grid frequency) in the output
current.
73. Wind Data and Energy Estimation
- Wind speedsare usually measured as 10 minute averages
- Wind roses :vary from one location to the next As an example,
take a look at this wind rose : Although the primary wind direction
is the same, Southwest, you will notice that practically all of the
wind energy comes from West and Southwest, so on this site we need
not concern ourselves very much about other wind directions.
- Isovents : Contours of constant average wind velocity, (Monthly
/ Quarterly / Yearly average )
- Isodynes : Contours of constant wind power ( Watts / m3 of the
area@ perpendicular to thewind flow )
- Seasonal Changes (magnitude & direction)
- Instantaneous changes (magnitude & direction)
74. Wind Data and Energy Estimation
- Factors which affect the nature of the wind close to the
surface of the earth
-
- Scale of the hour, month or year
75. Wind Data and Energy Estimation
- Hourly mean Wind velocity basic data (for many years), provides
the data for establishing the potential of the place for tapping
the wind energy.
- The scale of the month is useful to indicate whether it is
going to be useful during particular periods of the year.
- The data based on scale of the hour is useful for mechanical
aspects of design.
-
- Hourly Mean wind velocity
-
- Spell of low wind speeds (for alternatives / storage)
-
- Gusts ( structural design, safety measures )
76. Site Selection Consideration
- High annual average wind speed Strategy for siting-
-
- Survey of historical wind data
-
- Contour maps of terrain and wind are consulted
-
- Potential sites are visited - Best sites are visited
-
- Best sites are instrumented for one year
- Availability of anemometer data
- Availability of wind velocity curve at the proposed site to
predict the electrical power
- Wind Structure at the proposed site, for knowing departure from
homogeneous flow of the wind in direction and velocity.
- Altitude of the proposed site to examine the air density and
power in wind.
- Terrain and its aerodynamics
Anemometer 77. Site Selection Consideration
- Local ecology; bare rock, trees, grass, vegetation etc.
- Distance to roads or Railways
- Distance to local users , transmission line length, losses,
costs
- Nature of ground for foundations, corrosions
- Site ambient parameters - temperature, dust, humidity, icing,
salt spray etc.
78. Site Selection Consideration
- Best sites are found off-shore and at sea coast. Average 2400
kWh / m 2per year
- Second preference can be the sites in mountains. Average 1600
kWh / m 2per year.
79. The Characteristics of a good Wind Power site
- The characteristics of a good wind power site :
-
- The site should have a high annual wind speed
-
- There should be no tall obstructions for a radius of 3 km.
-
- An open plain or an open shore line may be a good location
-
- The top of a smooth, well rounded hill with gentle slopes
laying on a flat plain or located on an island in a lake or
sea.
-
- A mountain gap which produces to wind tunneling is good
80. Wind Energy Worldwide World Leaders in Wind Capacity
December 2003 Country Capacity (MW) Germany 14,609 United States
6,374 Spain 6,202 Denmark 3,110 India 2,110 Netherlands 912 Italy
904 Japan 686 United Kingdom 649 China 568 81. Wind Energy
Potential in India State-wise Power Installed Capacity in India (As
on 31 stDecember, 2003) Source: MNES 82. Wind Energy in India
Source: MNES 83. Wind Power Projects Source: MNES 84. Wind Energy
Potential & Installation (State-Wise) Source: MNES 85. Wind
Energy Potential & Installation (State-Wise) Source: MNES 86.
Question & Answer Session 87. Thank You Basics of Wind Energy
THE END