Wind turbines are the main elements of a wind farm (wind farm) and used to produce wind energy. Since the beginning of widespread use of commercial wind turbines in 1980, there has been a tremendous increase in terms of characteristics, efficiency, capacity and design them.
In the past two decades, wind turbines have increased in size by a factor of more than 100 times (from 25kW to 2500kW and so on), energy costs have been reduced by a factor of more than 5 times the rotor diameter wind turbines and increased by a factor of 8 times. The biggest wind turbines in operation currently has a rotor diameter of 126m and capacity of 7.58 MW (Enercon E126).
The evolution of the design of wind turbine technology is based on increasing reliability and efficiency, noise reduction, compatibility with the grid network and propeller aerodynamics effective. Over the years, different designs have been made of his prototype and today most of the commercial turbine design uses three blades horizontal axis. Vane rotor is connected to the transfer of power to a generator which in turn transmits electrical power to the transformer and eventually into the grid. Wind turbine rotor blades start spinning when the wind speed reaches 7.5 to 9.5 mi / h and continues until 50-55 miles / hour, the point where the wind is too strong.
Offshore wind turbines have a greater capacity to be explored. They are placed in the ocean to a depth of 30m in the form of wind and gain a stronger and more constant. At present, offshore wind power capacity is greater than about 50% of wind power on land. Until now offshore wind farms using wind turbines with a capacity of up to 5MW. Design of larger wind turbines are being explored and is expected to give impetus to build offshore wind farms are larger. Onshore wind turbines typically have a capacity in the range of 1 – 3mW.
Potential and new innovations in wind turbine design are constantly being exploited and mainly concentrated on the design of a propeller that is lighter with better aerodynamic features. This will allow the wind turbine has a higher performance (which also can take advantage of low wind speed) with increased reliability and better compatibility when connected to the grid. The concept of wind turbines today are based on the design of horizontal axis with three blades, variable symmetry and speed is the variable that most accounted for. Overall, the wind energy industry made substantial progress over the past two decades and this will play an important role in its aim to increase electricity production from renewable energy sources.