People have been harnessing the power of the wind since around 1000 B.C. The oldest and first known use of wind power was in sailing ships. This led to the development of the earliest sail-type windmills. The first windmills were used to grind, or mill, grains, thus the name windmill. The earliest known wind mills were built in Persia around 500 A.D.; they were used to process grains and pump water. The early windmills were vertical access designs, meaning they rotated parallel to the ground.
In the 1300’s some of the first windmills begin to appear in Europe; these were the earliest horizontal access windmills. No one really knows why there was a sudden shift from vertical to horizontal access windmill designs. It probably has a lot to do with the fact that the wind can only strike half the blades of the vertical windmill result in half the power transferred from the wind, rather than being able to strike all the blades on a horizontal design.
The horizontal mills did add complexity to the design as they required gearing mechanisms to transfer the horizontal rotation of the main shaft into the vertical rotation needed for turning the mill stones. The early mills used the gear mechanisms from horizontal water wheel driven mills. The Dutch were the first to offer new designs from the early post mills to tower mills. The primary difference between the post mills and the tower mills were the additional floors, with equipment powered by the post style mill atop the tower. The top floor of the tower mill could be rotated manually to make the blades face the wind, and the speed of the mill could be controlled by adjusting the angle of the blades in the wind. The sails were removable to protect the mill from strong winds during the stormy season, and the windsmith usually resided in the mill itself.
Over the course of about 500 years, these mills were incrementally improved, dramatically increasing their efficiency. By the time this process was complete, these early mills from the 1870s had most of the features of modern wind turbines. These mills were the “electric motors” of pre-industrial Europe. The applications of the windmills ranged from water well pumps; irrigation and drainage systems; grinding grain; sawing timber; processing spices, cocoa, paints, dyes, and tobacco; and even operating sewing machines. In the early 1900s, large steam engines began to replace the windmills.
During the next 120 years, between 1850 and 1970, over six million mostly small (one horsepower or less) mechanical output windmills were installed in the U.S. alone. These were primarily used across the Midwest to pump water from wells and ponds for watering livestock. The larger mills were used to pump water into towers for early steam trains, which provided the primary source of commercial transportation in areas where there were no large rivers. The first windmills to generate electricity began appearing around 1850, nearly 50-years after the invention of the electric light.
The first commercial wind-farm to generate electricity was built in Cleveland, Ohio, in 1888 by Charles F. Brush. It was a post mill with a multi-blade “picket-fence” rotor that was 56 feet in diameter and featured a large “tail” that was used to turn the rotor out of the wind. It was the first known windmill to use a gearbox to increase the rotational speed of the mill to the 500 RPMs needed to properly turn the generator. The mill was in operation for 20-years and produced 12 kilowatts of power. It was not nearly as efficient as newer turbine designs of equal size that are capable of producing 70 kilowatts, but it goes to show that wind power is not the new kid on the block.
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