Optimal layout design of floating offshore wind farms

Abstract

This paper proposes a method to optimize the layout design of floating offshore wind farms (FOWFs), in order to maximize the energy efficiency over a year. It is assumed that each wind turbine be installed on a semi-submersible platform, and that each floating platform be repositioned depending on wind conditions. The platform repositioning is realized by the aerodynamic force applied on the turbine's rotor, and the force vector on each turbine is adjusted by manipulating the axial induction factor and the nacelle yaw angle of each turbine. The design parameters for FOWF layout optimization are the neutral positions of the platforms, the anchor distance and angle, and the cable length. For a site with specific sea depth and wind rose, the layout design problem is formulated as a constrained optimization problem and is solved using an iterative optimization procedure. It is demonstrated that the developed method increases energy generation of a 6 × 6 FOWF by 2.4% compared to the regular layout, and gives comparable results with a published result that assumes a repositioning mechanism with additional actuators.