Torus Hull Articulated Tower for offshore wind turbines

Abstract

Recent years have witnessed significant advancement in offshore wind energy production. In order to achieve cost-effective solutions for intermediate water depths, there is a growing demand for wind turbine support structures with less steel compared to the existing ones. This study introduces a novel articulated tower concept termed “Torus Hull Articulated Tower” (THAT) for supporting an offshore wind turbine at a water depth of 75 m. The proposed concept incorporates a torus hull connected to a centrally located column with a system of pre-tensioned tethers. The preliminary technical feasibility of the concept has been checked by numerical analysis considering operating and parked conditions. A fully coupled analysis approach has been adopted for solving the associated aero-hydrodynamics-multibody mooring system problem. Acceptance criteria in terms of the maximum acceleration at the nacelle level and the platform pitch angle have been considered. The results show that the current concept can satisfy the required acceptance criteria. It has been concluded that the proposed structure could considerably reduce structural steel consumption compared to the existing concepts available in the literature. A sensitivity study on the structure's performance with respect to its major parameters is also included.