The geotechnical challenges facing the offshore wind sector

The offshore wind sector is undergoing rapid expansion across Europe, driven by the demand for renewable energy and uncertainties regarding fossil fuel supplies. The proposed wind farms are creating significant geotechnical challenges, particularly in terms of efficient foundation design. The majority of wind farms constructed to date have been founded in water depths of less than 30 m. However 70 of wind farm developments to be undertaken over the next 10 years will be located in water depths of between 30 and 70 m. In addition, because of developments in turbine technology, larger 5 MW turbines are coming into operation. The combined effect of larger structures and greater water depths leads to significantly increased vertical, lateral and moment loading on turbine foundations. This paper considers some aspects relating to the reliability of design methods for monopile and jacket structure foundations used to support the next generation of wind turbines.