Integrated Nature-Inclusive Design of the Innovative Tri-Suction Pile Caisson Offshore Wind Turbine Foundation

Abstract The Tri-Suction Pile Caisson (TSPC) is an innovative Offshore Wind Farm (OWF) foundation that will be installed with proven noiseless suction technology. To further enhance its ecological advantages for marine ecosystems such as the Southern North Sea, in this study we focus on incorporating Nature-Inclusive Design (NID) in the early design phase of the foundation. To that end, tailored ecological components are conceptually designed aiming to increase cost-efficiency, address technical interfaces and upscale desired ecological impacts. As opposed to conventional add-on design approaches, ecological components are designed to be well integrated on the TSPC foundation, requiring no further offshore installation works after the foundation has left the assembly yard for installation, thereby significantly reducing costs. This paper first presents the economic, technical and ecological criteria considered in the design phase as well as the four integrated conceptual NIDs developed for the TSPC. While the ecological performance of the proposed NIDs will have to be verified in the field, in this study we perform a verification of the hydraulic performance of the NID-enhanced TSPC, by conducting basin experiments that represent typical offshore conditions involving waves, currents and a mobile seabed. By accounting for NIDs already in the design phase, we show that technical risks and economic investments can be better managed thereby improving the ecological return on investment. This design approach contributes to a seamless upscaling of the desired ecological impact for marine ecosystems.