Beneficial Wave Motion Response for Wind Turbine Support TLPs with Synthetic Rope Tendons

As the offshore wind industry matures and projects begin to expand to deeper water regions, various floating systems are being considered to support wind turbines. This paper explores the feasibility of a Tension Leg Platform (TLP) support system anchored with synthetic rope tendons attached to a gravity base template to provide a platform for a wide range of water depths with acceptable operating nacelle accelerations. In this paper, the NREL 5MW wind turbine is selected in order to provide a comparison to previous studies of steel tendon TLPs. A fully-coupled numerical modeling tool is used to assess the effects of extreme irregular sea loads on the TLP. A series of numerical simulations are carried out to compare the response of a Single Column (SC) TLP for three different water depths and three different environments. The responses are compared with the steel tendon model. The use of synthetic rope tendons potentially offers more efficient installation options and enlarges the range of acceptable water depths. The use of a gravity base/suction pile foundation may improve the installation cost and schedule. The fully coupled nonlinear, time domain analysis tool used provides a unique look into the fully operating wind turbine under stable motion characteristics of the TLP.