A wind turbine is a rotary device that draws energy from the wind. This is different from a windmill, which draws energy from the wind but that energy is directly converted into mechanical energy used by some sort of machinery. Wind turbines are converted into raw electricity.
There are two main types, horizontal and vertical axis, of which the horizontal axis is more common. What are the differences between these two? Horizontal-axis turbines have the main rotor shaft and generator at the top of the tower. Horizontal axes must be pointed into the wind in order for them to work properly. However, the structure of the blades facing the wind also gives them a great angle of attack, which is the angle at which they have contact with the wind. This insures that the blades will be very efficient when converting wind to energy. Vertical-axis turbines are basically the same, except the axis is vertical, and they have the advantage of not having to face the wind.
Wind turbines are made up of three main components, the rotor component, generator component, and structural support component. The rotor component makes up about 20% of the cost, and consists of the blades. The generator component makes up 34% of the cost, and consists of the electrical generator, the control electronics, and usually a gearbox component for converting the low speed incoming rotation to high speed rotation which is better for generating electricity. Finally the structural support component makes up about 15% of the cost and consists of tower and rotor yaw mechanism.
Installing wind turbines can be a great way to save money on your electrical bills and create your own energy. They can be bought pretty inexpensively or you can even build your own and get the supplies to do it for even cheaper. If you are interested in building a basic wind turbine to see how it works, you should buy an educational wind turbine kit to get you started.