Mankind is using renewable power of wind with the help of windmills from over the period of time. A windmill is a machine or structure which converts wind energy into mechanical energy with the help of blades known as sails, which is used to grind grain; saw timber and pumping of water for irrigation and water supply.
The first working windmill was found in 9th century in Persia and was a vertical type of windmill with six to twelve sails. Such kinds of windmills were pretty familiar in Most of the Islamic countries and later the European countries knew about it by Islamic Spain. In 13th century vertical shaft windmills with rectangular sails were found in China.
In 12th century different design was introduced in northern France and that became standard for Europe. The design was such that the horizontal shaft was mounted to a vertical body that could be turned to face the way of wind.
In thirteenth century, windmills were mostly built up of brick with a wood cap that can be rotated rather than the body of a mill and this made possible to build taller windmills along with larger sails to work even at low wind.
At the rear of the cap, a small supporting set of sails, called as fantail helped sails facing the direction of wind. As industrial revolution began windmills became less important and were mostly replaced by steam and the internal ignition engines. By the end of 19th century, 100,000 windmills were present in Holland but today there are only 1000 windmills remain. In US there were six million windmills by the end of 19th century of which only 15,000 remain.
In current scenario windmills are more probably called as wind turbines which are used to generate electricity from wind power. The biggest turbine can generate up to 6 MW of power.