Changes
* It requires cheaper foundations
* Easily intergrated integrated with the electrical- grid network
* cheaper Installation and access during the construction phase.
* It can be operated and maintained easily and cheaply
so, large turbines can be installed
* Noise pollution is also not a factor because these are too far from shores
* Less affected to turbulance turbulence in wind and low wind shear<br/>
|-
| Disadvantages
* Neagtive Negative visual impact or noise.* Limted avaliability Limited availability of lands* Restrictions asscociated associated with obstructions like buildings, mountains, etc.
* Noise pollution
* Afftected Affected to more turbulanceturbulence
Sources:[http://library.thinkquest.org/06aug/01335/wind%20Power.htm Wind Power],[http://www.ehow.com/list_5938067_types-wind-farms-there_.html Types of Wind Farms]
| Disadvantages:
* Installing offshore windturbines wind-turbines is much more complex and costly
* Connection to the utility grid is also much more complex and expensive
* Operation and maintanances maintenance is also a complex task with off shore wind turbines
Source:[http://www.offshorewindenergy.org/ca-owee/indexpages/Offshore_technology.php?file=offtech_p2.php Offshore Technology]
|-
===Tower===
A tower that supports the nacelle and rotor hub at its top. These are made from tubular steel, concrete, or steel lattice. Height of the tower is an important in design of HWAT. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity. Generally output power of the wind system increase with increase in height and also reduces the turbulance turbulence in wind. The theoritical theoretical view of tower height versus power out is shown in figure 7 .
click on the link to get more about size of the towers
|[[Image:turbular.jpeg|200px|center|thumb|Fig 8(a) [http://americanrenewableenergycorp.com/towers Tubular tower]]]
|-
| '''Lattice tower''': A Lattice tower can be constructed with perfectly shapped shaped steel rods that are put together to form a lattice. These towers are very strong and inexpensive to manufacture and easy to transport and erect.
|[[Image:lattices.jpeg|center|200px|thumb|Fig 8(b) [http://www.mywindpowersystem.com/2010/03/wind-power-stats-quiet-critics/ Lattice tower]]]
|-
|[[Image:guyed.jpeg|center|200px|thumb|Fig 8(c) [http://itgiproducts.com/energy/windTowers.asp Guy tower]]]
|-
| '''Tilt up wind towers:'''These type of towers are used for consumer wind energy. These turbines have locking system, while working the turbine is locked. It can easily ulocked locked and lowered to ground to perform repairs.
| [[Image:tiltup.jpeg|center|200px|thumb|Fig 8(d) [http://itgiproducts.com/energy/windTowers.asp Tiltup tower]]]
|-
| It requires more complex design due to sustain of wind shocks. It is also less stable. It saves the cost and weight of one rotor blade.
[[Image:two.jpeg|center|300px|thumb|Fig 9(b) [http://www.trendir.com/green/?start=15 Two blade turbine]]]
|Modern wind trubines turbines uses three blade concept. Because this structure have hight strength to withstand heavy wind stromsstorms. Less effect due to towe tower shadow. Produces high output
[[Image:three.jpeg|center| 200px|thumb|Fig 9(c) [http://www.china-windturbine.com/wind-turbines-blades.htm Three blade turbine]]]
|}
'''Hub'''
A rotor hub is provided for coupling a wind turbine rotor blade and a shaft. The hub assembly consists of hub, bolts, blade bearings, pitch system and internals
. Rotor hubs are made with welded sheet steel, cast iron, fored forged steel. The types of rotor hubs are * Hingeless Hinge-less hub
* Teetering hub
===Anemometers===
Wind speed is the most important factor for determing determining the power content in the wind. The power content in the wind is directly proportional to cube of the wind velocity. Measuring wind speed is important for site selection. The device which is used for measuring wind speed is called anemometer. These are usally usually located on top of the nacelle.
[[Image:windvane.png|center|300px|thumb|Fig 14 [http://www1.eere.energy.gov/windandhydro/wind_how.html Anemometer & Wind vane]]]
