Techno-economical Layout and Turbine Type Optimization for Floating Offshore Wind Farms: A ScotWind Portfolio Study

Abstract

Abstract This paper explores state-of-the-art modelling and optimization methods for floating offshore wind farms. A case study is performed on three ScotWind lease areas, where the optimal turbine type and layout is assessed in terms of Annual Energy Production (AEP) using a multiple-step optimization strategy. The numerical setup relies on TopFarm (DTU), ORBIT (NREL) and Peak Wind’s in-house codes and expertise. The portfolio study reveals that across all sites, using wind turbines of higher single capacity (15MW against 11MW and 14MW) is more optimal, as the scaling-up of the nameplate power allows to save costs. The LCOE decreases to around 100$/MWh, which is consistent with the predictions for commercial floating wind projects in the coming years. The optimal layouts show an alignment of the turbines perpendicularly to the prevailing wind direction, in which their spacing is also greater to minimize the wake losses. Sensitivity analyses are carried out on key project-specific parameters and optimization inputs, such as the initial positions of the turbines, showing how a multiple-start strategy explores the whole design space and allows to validate the optima found.