II / It is necessary to have an uniform, frequent and rather strong wind to let the wind turbine turn.

For example, in France, to be profitable, the annual average speed of the wind must be between 21 and 25 kilometers.

- There are three primary different types of wind turbines: savonius VAWT ,Modern HAWT , Giromil VAWT

- It works as a bicycle dynamo : the wind induces the blades, then, the dynamo starts out. This system produces electricity which is stocked.

- The recoverable power of electricity producted by a wind turbine is calculated by this formula :

- [pic]

ρ= density of the air

S= surface

V= speed of the wind

Cp= performance coefficient

the maximum yield of a wind turbine is about 60% (percent) even if there are wastes of energy in the machine.

III / Denmark: 600 watts per person

Spain: 425

Germany: 292

USA: 89

French: 56

We can build wind turbines : in sea, on earth, where the wind blows sufficiently, as in the plains, in the cyclones’ zones, in altitude. However, in sea they produce more electricity : 5 MW against 3 MW on earth (we speak about wind turbine offshore). France does not possess any offshore park but projects are in runs.

IV / The energy produced by a wind turbine is a renewable energy: it is durable and clean, it does not use some fuel, it is not a greenhouse gas. Moreover it helps to reduce the transmissions of CARBON DIOXIDE. That is why every megawatt per hour helps to reduce of 0,9 ton the rejected transmissions of CARBON DIOXIDE per year by the electricity production of thermal origin.

Nevertheless that creates sonorous nuisance (when there are wind turbines next to houses) and visual nuisance but it is an energy that is only auxiliary. That creates radars' and television's