In recent years, wind energy is the fastest growing clean and renewable energy source in the world. However, most of the wind farm development has been limited to the land space and shallow water regions. Recently, several European countries (including Spain), USA and Japan started to plan floating offshore wind farms. In June of 2009, the first floating offshore wind turbine (Hywind) of the world was installed by Statoil-Hydro and Siemens on the coast of Karmøy, near the port of Bergen, Norway. In general, floating offshore wind farms are considered to be more difficult to design and install. However, in deep waters they are less sensitive to the space availability, noise restriction, and visual pollution, among others. Moreover, the wind power generation is more effective due to that floating offshore wind farm are exposed to a much stronger and steadier wind field.