Wind power has always supplied the driving force to sailing ships and Stata and used to operate the windmills. The use of this type of Energy Sector and later fell into disuse with the Electric Energy Transmission and Availability EXTENDED with a low cost of engines powered by fossil fuels.
However, the recent attention given to Climate Change, the need to increase the share of clean energy and fears of a future decrease in oil Availability Have Promoted a Renewed interest in the Production of Electricity from Renewable Sources and then also from wind .
This type of energy, in comparison to other renewable energies, Require Lower investment and uses a natural resource generally available everywhere and particularly usable In temperate areas, where the majority of industrially developed nations.
During the last decade of the 20th Century sono stati built and tested Several wind turbine models: with horizontal and vertical axis rotors, with varying number of pale, with the rotor placed upwind or downwind of the tower, etc.
To the horizontal axis turbine with a three-bladed upwind rotor is shown and the type usually more appropriate and has therefore Had a
Significant development, marked by SIA A Rapid Growth in size and power, SIA wide dissemination.
For good to take advantage of the kinetic energy of the wind and converts it into electricity Available for the feed-in or for the supply of parallel loads, A wind turbine uses diversification components mechanical and electrical.
In particular the rotor (pale and Hub) extracts the wind energy to generate mechanical energy of rotation and is the “first mover” dell’aerogeneratore, WHILE mechanical Energy Conversion into electricity and performed by an electric generator Second appropriate configurations.
In summary , the major components that make up an aerogenerator GreenStorm horizontal axis are :
- the blade support
- pitch angle actuator
- main support
- Aircraft warning lights
- mechanical brakes
- Power converter and electric devices of control and protection
- The structure of the spacecraft
- Tower of support
- The drive for the yaw organ
A wind turbine or wind turbine converts the kinetic energy of wind into electrical energy without the use of any fuel and passing through the conversion stage into mechanical rotation energy carried by the blades.
The turbines can be to “lift” or “resistance” in the function of which of the wind-generated power and exploited as a “driving force.”
To understand the principle of operation of a wind turbine we refer to the turbines currently most widespread, namely those to “lift”; in them, compared to those for “resistance”, the wind flowing on both faces of the blade, which present different geometrical profiles, thus creating at the upper surface of a low pressure area than the pressure on the lower face.
This pressure difference produces on the surface of the wind blade a call aerodynamic lift force, analogously to what happens for the
aircraft wings. The lift on the wings of an airplane is able to lift it from the ground and to support it in flight, while in a wind turbine, as the blades are placed on the ground, determines the rotation around the hub.
Simultaneously it generates a resistance force that opposes the motion and is perpendicular to the lift.
In correctly designed turbines, the lift-to-drag ratio is high in the field of normal operation.
A wind turbine requires a minimum wind speed (cut-in) of 3-5 m / s, and delivers the design power at a wind speed of 12-14 m / s. At high speeds, generally higher than 25 m / s (cut-off) the turbine is stopped by the braking system for safety reasons.
The block can be done with real mechanical brakes which stop the rotor or, for variable pitch blades “hiding” the same to putting wind in the so-called position “flag.”
The main advantages of wind power plants can be summarized as:
- distributed generation
- Efficient conversion of wind energy into electrical energy ( rendimentoteorico 59% )
- no emission of polluting substances
- saving of fossil fuels
- reduced operating costs ( there is no fee for the delcombustibile supply ) and maintenance
- Easy dismantling of the wind turbines at the end of life ( 20-25 years )
- The production capacity dell’aerogeneratore varies from a few hundred to a few MW DIW , to meet the needs of both singoleabitazioni , both industrial use or placing on the network (via wind farms)
The variability and unpredictability of the wind instead represent the overwhelming disadvantages of electricity derived from wind power .
To estimate the energy producibility of a wind turbine is not sufficient to know the average wind speed at a given site , but important is also good to have data available that indicate , for a given period ( eg . 1 year) , the histogram of percentage duration of the different wind speeds , which are generally the average measured value in 10min through anemometers installed on anemometer towers .
The overall energy producibility of a wind farm is obtained by adding the producibility of the individual turbines installed and multiplying the result by the appropriate corrective factors to take into account the possible aerodynamic interference between turbines and losses in the connection between the various units and between plant and the electricity grid .