Introduction - Wind Energy: Renewable Energy and the Environment - page 2

FIGURE 1.1 Dutch windmills, World Heritage Site, Kinderdijk, The Netherlands.
so the rotor would be perpendicular to the wind. Others would have a small fan rotor to yaw the big
rotor. The rotational speed and power were regulated by the amount of sail that was on the blades. The
miller and his family lived in the bottom of the windmill, and the smoke from the fireplace was vented
to the upper floors to control insects. For the thatched windmill, fire was a major hazard.
1.1.2 F ARM W INDMILL
Farm windmills were one of the primary factors in the settlement of the Great Plains of the United
States [4]. From 1850 on water pumping windmills were manufactured in the tens of thousands.
The early wood machines ( Figure 1.3 ) have largely disappeared from the landscape, except for an
isolated farmhouse or in museums.
By 1900, almost all windmills were made of metal, still with multiblade vanes, and the fan
or blades were 3-5 m in diameter ( Figure 1.4) . Although the peak use of farm windmills was
in the 1930s and 1940s, when over 6 million were in operation, these windmills are still being
FIGURE 1.2 Thatched Dutch windmill. Notice water flow at bottom of windmill into the canal. Author in
much younger days next to helical pump.