Offshore wind farm optimization, investigation of unconventional and random layouts

Abstract

This project aims at investigating whether or not unconventional and/or random offshore wind farm layouts lead to better performance of the farm. The determination of each solution is based on the estimated value of the Levelized Production Cost, thus the cost per produced unit of energy (i.e., ecents/kWh). For the purposes of the current research a previously developed Matlab code is used. Due to some restrictions that had been adopted by the original composer of the code, the tool was updated and extended so that it is able to evaluate more random-shaped offshore wind farms. The optimization of an offshore wind farm layout is a multidisciplinary problem, which includes several design variables. In addition various restrictions should be considered if the purpose of setting the problem on a more realistic basis is desired. In this study due to the limited time as well as narrow computational resources, only some of these parameters are considered. Among others they include, the wake effect, electrical losses and a site specific wind rose. A reference offshore wind farm is set, and in detail is investigated, by a deterministic and stochastic approach, the effect of a) different separation distance for each row and column of the wind farm, b) displacement of individual wind turbine(s), c) discard of specific wind turbine(s). These alterations try to achieve the increase of the energy production, either by maximizing the energy output of the wind turbines, due to the decrease of the losses caused by the wake effect, or by minimizing the electrical losses. Moreover, a better layout design could be realized by reducing the costs which refer to the overall project. In addition to the aforementioned listed alterations the case of the Horns Rev offshore wind farm is studied. This case is investigated by the deterministic and stochastic approaches, as the previous cases and the results are compared to the ones included in already published bibliography. Overall, it was shown that the layout design according to the characteristics adopted in this research could lead to a more efficient offshore wind farm. In the majority of the cases it is seen that the decrease of the LPC is mainly a result of the cable cost and losses. When the small test wind farm is considered, it is noticed that the structured approach of unconventional layouts resulted in better values for the LPC in comparison with the more random approach.