Naval Architecture Methods For Floating Wind Turbine Installation

Floating offshore wind turbines are becoming an important part of renewable power generation, offering an opportunity to deliver green energy, in new areas offshore. The floating nature of the substructures permits wind turbine placement in deep water locations. This paper presents the naval architecture design methods requirements for the installation of floating offshore wind turbines. It is expected that floating offshore wind turbines will become an important part in the production of renewable energy. Naval architects have a role in the design, construction and offshore installation of floating offshore wind turbines. This paper considers the installation phase of floating offshore wind turbines, including the load-out, fit-out, tow-out and connection of moorings and dynamic cable. The results show that port facilities for the construction and fit out are limited by alongside water depth, laydown area and quay strength for large onshore cranes. This paper covers port requirements, different floating offshore wind turbine substructures and various installation vessel requirements (FOWT). Most existing floating offshore wind turbines are barge, semi submersible and spar types and their installation use methods developed for offshore structures. Naval architecture calculations considered are weight control, ballasting intact stability, one compartment damage stability, ocean tow motions and bollard pull. In addition there are mooring calculations required for temporary conditions plus installation of export and dynamic cables. The Tension Leg Platform (TLP) floating wind turbine are being considered as an option but have minimum water plane area and hence have low intact stability during ocean tow and thus TLPs may require modified crane vessels for offshore installation or temporary buoyancy which improves intact stability. The weather window limitations for the various substructure types for the transportation to and from the offshore site and during the connection of mooring lines and electrical cables are included in the paper. The paper will present recent advances in the installation of floating offshore wind turbines.