Design and Construction Considerations for Offshore Wind Turbine Foundations in North America

The wind energy sector is rapidly growing driven by the growing demand for sustainable energy. The past years have seen the wind industry develop and test not only more efficient, but also much larger wind turbines than those currently in use. These large wind turbines will place large demands on the support structures and foundations. As an increasing number of wind farms are being planned offshore in water depths of over 50 m, the combination of water depth, the increased windmill tower heights and rotor blade diameters will create loads that make foundation design very complex. Moreover, offshore foundations are exposed to additional loads such as from ocean currents, storm waves, ice and potential ship impact. All of these factors pose significant challenges in the design and construction of wind turbine foundations. This paper presents the various issues facing the designer in designing and constructing offshore wind turbine tower foundations. Current practices are examined and summarized to assist developers in foundation type selection and design.