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Wind turbines use some of the very latest technology – mechanical, electronic, IT, composite materials – enabling the transformation of kinetic energy into electric energy.
Wind turbines consist of :
- a tower, usually made of metal, coloured white to meet aeronautical requirements, with a diameter of about 4 to 5 meters at the base and between 40 and 100 meters in height.
- a rotor with 3 blades made of composite materials, each being 30 to 50 meters long and fixed to the center. The blades pivot around an axis to regulate the speed of rotation of the rotor (between 8 and 18 rotations a minute in production).
- a nacelle (or pivoting pod) which orients itself automatically to the direction of the wind. The rotor which turns the alternator is within the nacelle. The nacelle is accessed via the interior of the tower
The main characteristic of a turbine is the power of its alternator, which is measured in kilowatts. Turbines that are currently being installed generate between 1,500 and 3,000 kilowatts (or 3 megawatts).
The choice of machine is crucial and depends on the particular wind characteristics of a given site.
To begin operating, a turbine requires a minimum wind speed of 10 km/hour. The optimal speed is between 40 and 45 km/hour. Over 90 km/hour the turbine stops and goes into protection mode. Braking is assured by the pivoting of the blades. In addition, a security brake can block the axis of the rotor.
The energy produced by a turbine is measured in kilowatt hours. It depends on the average wind speed on the site.
A computer system coupled to the telephone network is used for remote management of all the wind turbines in the park.
For an average site with an average wind capacity of 7 meters per second, the electricity production of a farm of 4 turbines of 2 MW can supply the electricity needs (without electrical heating) of around 12,000 people (on the basis of 2,000 kWh per year per person). |
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