Wind-generated electricity is becoming an increasingly attractive source of power, as it is recognized as providing an environmentally compatible source of electricity. Wind energy is the world’s fastest growing energy source on a percentage basis (with an annual increase approaching 32%) and its growth is forecast to continue at a double-digit pace into the next decade. The process of the wind turbine is a fairly simple one. The wind is used to generate mechanical power or electricity. A range of different wind speeds passing over the blades is converted into mechanical power. Wind turns the blades and the power from the rotation of the wind turbine rotor is transferred to the generator through the nacelle that houses the gearbox, low and high speed shafts, generator, controller, and brake. To get the most reliable energy production possible, machines have to be kept in excellent condition. Lubrication is another important aspect that contributes to turbine reliability and long service intervals.