The horizontal is used more often than the vertical. Listed below are the two types of axis turbines and how important each of them is to the world of wind power.
The horizontal axis wind turbines or commonly known as HAWT consist of a main rotor shaft and a generator for power that is set on top of a long tower and has to be pointed in the up direction into the wind. An old-fashioned wind vane points the smaller turbines. The larger turbines have a wind sensor along with a servomotor. The majority of the larger turbines have a gearbox that can control the rotation of the turbine blades. They can go from slow to fast just by adjusting the gearbox.
Some of the horizontal turbines are called Windmills, American style farm windmills, Common modern wind turbines, ducted rotor turbines, co-axial multi rotating. They all have a special purposes and special uses.
The vertical axis wind turbines also called VAWT have a main rotor shaft that runs vertical. The advantage over the horizontal turbines is that the way the turbine is arranged the generator and gearbox can go on the bottom, near the ground and the tower doesn’t have to be used to support the axis. But there is a downside too, the torque pulsates and it is very difficult to mount vertically.
Some of the vertical axis wind turbines are the Darriues windmill, the Giromill (which is part of the Darriues) and the Savonius windmill. Each on of these has a specific purpose and presence. The vertical turbines have some advantage over the horizontal but eventually it is the horizontals that are used more often.
