As wind turbines increase in size, numbers, and their operating conditions become more extreme, a number of current and future tribological challenges exist. The supervisory control and data acquisition system (SCADA) installed at individual wind turbines records turbine specific information. Quite often, the information recorded by the SCADA systems is used reactively when a failure occurs the wind turbine. This Book presents approaches to utilize SCADA system prognostically. A variety of ways in which the wind turbine data can be utilized in performance monitoring are discussed with real failure cases. Approaches discussed here provides a cheap, but effective ways to fault prognosis and performance monitoring of wind turbines.