Design and Analysis of a Novel Semi-submersible Floater Supporting a 5MW Wind Turbine

Abstract

The wind industry has been rapidly evolving in recent years, moving from onshore to offshorelocations. For deep waters, floating wind turbines are more cost-effective than bottom-fixed ones,and semi-submersible floating wind turbines are especially advantageous compared to other con-cepts because of their relatively small draft and good towability for installation. This masterthesis focuses on preliminary design and analysis of a novel semi-submersible floating wind turbinesupported by a twin fish floater and positioned by a single-point mooring system. Hydrostaticand hydrodynamic analysis are first carried out to select a floater with decent dynamic properties.Then, a two-component mooring system is designed with a turret connected to the twin fish floater.Dynamic analysis of the coupled wind turbine-floater-mooring system is performed under a few ex-treme environmental conditions. Results identify the motion characteristics of the twin fish floaterwith single point mooring and show that the extreme mooring line tensions satisfied the designcriteria. This study contributes to a better understanding of the proposed novel system underwave conditions. In future, detailed structural analysis will be included in a more comprehensivestudy to evaluate the feasibility of the concept.