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 the uncertainty regarding fossil fuel supplies. The proposed wind farm developments 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 thirty meters. However 70% of the proposed turbines over the next 10 years will be located in water between 30 and 70m, which increases the lateral loads and moments applied to the foundations. This paper outlines the geotechnical design considerations for turbines located in relatively deep water. The empirical design models commonly used for monopiles and jackets are briefly discussed, in order to highlight the limitations in existing design procedures, originally formulated for the oil and gas sector.