A small wind turbine is a device that converts the kinetic energy of wind into clean electricity and has a capacity rating not exceeding 100 kilowatts. The turbine's rotor collects kinetic energy from the wind and turns it into rotary motion that powers a generator.
Most small wind turbines have two to three blades attached to a rotor. When air blows over the blades, they lift and rotate, causing the rotor to spin. The rotor is attached to a low-speed shaft and a high-speed shaft. The two shafts are joined inside the gear box, which increases rotational speed by up to 300 percent to produce the number of cycles needed to drive the generator. The generator then produces 60-cycle AC electricity.
Small wind turbines are usually in close proximity to the locations that they are powering, including water pumping stations, telecommunications dishes and single-family homes. They are also used to provide electricity to schools, communities, farms, ranches and industrial facilities. When connected to photovoltaic systems, batteries or diesel generators, they are useful in environments where utility grids are unavailable.
There were over 150,000 small wind turbines installed by the end of 2012, and as of 2015, the U.S. Energy Department continues to work on improving the reliability and cost effectiveness of wind turbine technology.