According to the Department of Energy, wind turbines generate electricity when the wind moves the fan blades, which are connected to an electric generator via a central shaft. As the blades turn, they turn the generator, creating an electric current.
The heart of a wind turbine is its generator, a machine that converts the rotational energy of the fan blades into electrical power. It does so through the movement of conductive wire inside a magnetic field, with the wire loops or brushes connected to the central shaft of the turbine's propeller. When the wind turns the blades at an appropriate speed, the moving wire becomes charged in the generator's magnetic field, producing an electric current. Turbines may be horizontal, in which case they look like giant pedestal fans, and often have the capacity to turn to follow the direction of the wind for maximum power production. Vertical turbines look like eggbeater blades, and can function when the wind hits them from any direction. The electricity from wind farms flows only when the wind is blowing, which is why many regions of the country that have invested in wind power use it as a supplemental source along with conventional or other renewable methods of energy generation.