When Monopiles Don’t Work: Fixed Wind Foundation Selection

Presentation Description: Monopiles are the de facto solution for offshore fixed wind developments for good reason. They are a simple low-cost solution with well-established fabrication, transportation and installation procedures. However, the industry drive for larger higher power turbines and expansion into deeper waters is pushing the technical limits and feasibility of this field proven industry solution. As an example, the overturning moment for a 15MW turbine more than doubles in comparison to a 10MW turbine, necessitating much larger diameter monopiles and associated installation vessels and hardware.
Alternate solutions to conventional monopiles include jacket based structures or the use of alternate seabed interfaces such as suction pile or gravity based systems. For cases where monopiles prove to be technically challenging these alternates can be evaluated. In this evaluation consideration of the turbine size, water depth, geotechnical conditions, available installation vessels and local regulatory requirements can all factor in to select the optimum solution. The resulting foundation selection is becoming increasingly development specific.
This presentation will discuss each of these considerations and their importance. A methodology will be described that will take into account the full life cycle of the foundation and weight each factor (e.g. manufacturability, installation, decommissioning, etc) allowing the different foundation solutions to be ranked and the optimum solution selected.