Wind energy has long been recognised as a potentially abundant source of clean and renewable mechanical and electrical power. History records that wind energy has been harnessed by man since about the year 2000 BC when windmills were used for energy production in Babylon and China. An ancient Persian vertical-axis windmill of about 7th century vintage is shown in Fig. 1. Windmills appeared in Europe in the 12th century and flourished until the 19th century as one of the few forms of rotary mechanical power. The Dutch windmill achieved lasting fame as the subject of paintings and etchings by the Dutch Masters including Rembrandt and van Ruisdael. Rembrandt's etching ‘The Windmill’ shows the fine detail of a 17th century windmill in Amsterdam.

The final versions of Dutch and English windmills were relatively sophisticated machines, well suited to the tasks of grinding grain and other materials, pumping water and sawing wood. Steam power came to displace wind power in the 18th century, and windmill numbers diminished rapidly during the late 19th and early 20th centuries. Nevertheless, working examples of traditional windmills can still be seen in Holland, England and on the Greek islands.