Wind power is the use of energy to generate useful work. Historically, wind power was used by, and, but today it is mostly used to generate. This article deals only with wind power for electricity generation. Today, wind power is generated almost completely using, generally grouped into and connected to the. The windwheel of (10–70 CE) marks one of the first recorded instances of wind powering a machine. However, the first known practical wind power plants were built in, an Eastern province of (now Iran), from the 7th century. These were vertical-axle windmills, which had long vertical with rectangular blades. Made of six to twelve covered in ree.