nacelle, parts of a wind turbine

The nacelle is the housing of a wind turbine that contains the key components of the turbine, including the gearbox, and the electrical generator. Service personnel may enter the nacelle from the tower of the turbine. To the left of the nacelle we have the wind turbine rotor, i.e. the rotor blades and the hub.

Kinetic wind energy is converted to electric energy by a wind turbine. In a typical, modern, utility scale wind turbine, the kinetic energy in the wind is converted to electricity by the rotational motion of a two or three-bladed rotor assembly. The rotor turns a shaft which transfers the motion into the nacelle (the large housing at the top of a wind turbine tower). Inside the nacelle, the slowly rotating shaft enters a gearbox that greatly increases the rotational shaft speed. The high-speed shaft is connected to a generator that converts the rotational movement into electricity at medium voltage (a few hundred volts). Electricity flows down heavy electric cables inside the wind turbine tower to a transformer, which increases the voltage of the electric power to the distribution voltage (a few thousand volts). The reason that voltage is “stepped-up” is that higher voltage electricity flows more easily through electric lines, generating less heat and power loss. The distribution-voltage power is then sent to an electrical grid substation where the voltage is again increased dramatically to transmission-voltage power (a few hundred thousand volts) and transported via long distance transmission lines to distant cities and factories.