Effect of cost elements on optimum layout of an offshore wind farm

• Considering only turbine cost as the wind farm cost will result in an unrealistic optimum layout. • Optimized layout for LCOE may be different from the optimum layout for COE. • Non-homogenous farms impose a higher LCOE which makes them less appealing to developers. The main goal in wind farm layout optimization is to minimize the cost of energy (COE). This can be achieved by reducing the costs associated with the wind farm and/or increasing the power output, as both factors directly impact the COE. In this study, we focus on minimizing the levelized cost of energy (LCOE) by comprehensively considering all costs throughout the lifetime of a wind farm. To investigate the impact of the LCOE on optimization process, we examine a non-homogeneous wind farm. Consequently, we let the optimization process choose between two distinct categories of commercially available turbine sizes. The proposed cost model includes expenses associated with the key components involved in design, construction, and operation and maintenance processes throughout the wind farm's lifespan. Considering the change in wind speed, we first study two cases of identical turbines and a combination of different sizes of turbines by single and multi-objective optimization processes to minimize LCOE. While varying turbine sizes contribute to an increase in power production of the wind farm, the significant rise in elements of cost makes it impractical from a developer's perspective. Finally, we investigate the significance of considering different elements of cost in the objective function and emphasize the importance and superiority of the LCOE over the traditional COE.