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WIND ENERGY TECHNOLOGIES

This chapter describes the operation of wind turbine technology and provides an
overview of its applications. Some of this material also can be found on the Web sites
of the American Wind Energy Association, the U.S. Department of Renewable Energy
Laboratories, and the Danish Wind Turbine Manufacturers Association.

History of Wind Power

VERTICAL-AXLE WINDMILLS
The earliest historical reference describes a windmill that was used to power an organ
in the first AD, which is credited to Hero of Alexandria. Also, as early as the ninth
century AD, vertical-axis windmills were used in Sistan, located in present-day eastern
Iran. The ancient Iranian windmill designs consisted of 12 sails covered with reed mat-
ting or cloth material. The windmills were used to grind cereals and pump water.
Similar types of vertical windmills, with rectangular blades, were used for irrigation
in the thirteenth century AD in northern China during the Jurchen Jin Dynasty.

HORIZONTAL-AXLE WINDMILLS
Horizontal-shaft windmills were used extensively by the ancient Greeks for grinding
flour. It has been recorded that on the island of Cyclades, millers received flour as pay-
ment for their services.
In the twelfth century AD, Flanders, France, and England used windmills extensive-
ly to grind flour. At present, there are many ancient Dutch windmills that are still
operating.
With the advent of the industrial revolution, the use of windmills as primary industrial
energy sources was replaced by steam and internal combustion engines. However,
steam engines had a lesser effect on some of the remotely located mills in England,
which were used as drainage pumps until the middle of the twentieth century.
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