Design and Installation of an Innovative Tension Leg Platform for 2 MW Offshore Wind Turbine at Baltic Sea

摘要

The Offshore Wind Resources in deep water, but also the currently experienced issues with conventional foundations, are driving the solution requirements for new offshore wind power platforms. The latest monitoring results of German offshore wind farms show the challenges the industry is facing. Ecological impacts as well as foundation technology issues are forcing the sector to look for alternatives. The presentation will introduce a technology of a floating TLP-structure with a specific mooring line configuration as an innovative foundation concept for offshore wind turbines suited for water depths greater than 30 meters. The unique aspect of the GICON TLP is its modular, frame-work structure which allows buoyancy and load transfer functions to be decoupled from each other and instead be applied to the specific structural elements. In contrast to classic TLP designs and semi-submersible floaters, additional stabilizing effect achieved by this additional bracing minimizes the movement of the entire system. Due to this stable behavior of the TLP standard offshore turbines as currently available in the market should be usable for this platform. Furthermore results from model basin tests will be described. Also the comparison of calculated and experimental data obtained by extensive tank experiments with a scale model of an offshore turbine at Maritime Research Institute Netherlands (MARIN) in summer 2013 will be presented. These experiments include wind and wave loads that represent different sea states of the proposed location for the full scale prototype. In numerical simulations the dynamic behavior of the TLP under linked hydrodynamic and aerodynamic loading is taken into account also regarding different geometric configurations of the mooring line system and various types of anchorage systems at the sea floor. Using characteristic Campbell-diagrams structural stiffness of each component is optimized aiming at a soft-stiff design of the TLP-structure. The results of the scaled tests at MARIN have confirmed that a superposition of internal forces of the moored structure in operation for wind and wave loads can be assumed. Numerical modeling validation is confirmed by tank tests. Data and video from the tank tests will be shared as part of the presentation. GICON researchers plan to install a full-scale pilot plant in the German Baltic Sea in 2016.