The first renewable source used has been wind power, that takes its name from Eolo the mythological Greek god of the wind.
The first use are in the maritime field of navigation and later in the agricultural field through the use of wind mills. The first wind mills were used in the 7th century AD by the Persians that were using wind turbines to water the fields and milling grain.
In Europe the first wind mills appeared in the Medieval age during the crusades, in particular in The Netherlands. The structure was made by a tower made of rocks, with on top of it a wooded rotating roof sustaining the post and the gearwheel system of the wind mill. From the top part stuck out an horizontal shaft to which was fixed an helix made of four or eight blades.
Subsequently the wind mill’s structure became technologically more complex with higher performances thanks to the discovery of the naval dynamic: by taking advantage of the lift (usable power perpendicular to the wind speed) instead of resistance, the result was an increase in energetic performances. Towards the middle of the 19th and the beginning of the 20th century thousands of wind mills became operational in Europe and in the USA, reinforcing their importance for agricultural and domestic usage.
In those years saw the light the first installation of power generators and the first wind plant was installed in the USA by Charles F. Brush. Afterwards with the increase of the power, thanks to the use of aerogenerators with higher performances, were realised the first horizontal axes plants with 1 to 3 blades.