6.3.3 Two types of wind turbines

1) Horizontal-axis design has two or three blades that spin upwind of the tower. A horizontal axis machine has its blades rotating on an axis parallel to the ground.

2) Vertical-axis turbines has vertical blades that rotate in and out of the wind. The vertical axis turbine has its blades rotating on an axis perpendicular to the ground. This drag-type turbine turns relatively slowly but yields a high torque. It is useful for grinding grain, pumping water and many other tasks, but its slow rotational speeds are not optimal for generating electricity. Vertical-axis turbines do not take advantage of the higher wind speeds at higher elevations (100 feet and so) above the ground vis-a-vis horizontal axis turbines.