Optimization of offshore wind farm power cable routing

Up to now methods to optimize cable route layout are only based on a flat seabed and do not take the seabed dynamics into account (Jenkins et al., 2013; Morelissen et al., 2003). The result of this approach is that power cable coverage is not guaranteed over wind farm design lifetime. Cable optimization is mainly executed based on shortest routes instead of cost reduction over the entire design lifespan. The aim of this research is to develop a Matlab based tool, which optimizes power cable route design based on expected morphological behaviour in the design lifetime of an offshore wind farm

Cable route optimization for offshore wind farms in morphodynamic areas

The aim of this paper is to optimize power cable routing in a wind farm based on the expected morphological behaviour in the design lifetime of an offshore wind farm. Up to now methods to optimize cable route layout in offshore wind farms are only based on a flat seabed and do not take the seabed dynamics into account. For offshore wind farms, migrating seabed features in the form of sand waves are of great importance and may significantly alter the position of the seabed over the life time of the wind farm. This paper discusses the optimization of power cable routing in a morphodynamic seabed by assessing the power cable burial depth in both the vertical plane, e.g. buried deeper in areas where future seabed lowering is expected, and in the horizontal plane, e.g. diverting the power cables around risk prone areas. Outcomes of the proposed method showed both cost and risk reductions for the Hollandse Kust (zuid) Wind Farm case study compared to state-of-the-art optimization based on a fixed burial dept

Numerical modelling of the migration direction of tidal sand waves over sand banks

Tidal sand waves are large-scale bed forms found in shallow sandy seas, which show a migration of several meters per year. Field data from the Dutch part of the North Sea revealed a migration pattern causing bidirectional migration of sand waves over a sand bank, resulting in sand wave migration uphill from both sides of the sand bank. In order to understand the physical mechanisms behind this migration behaviour, we study the inclusion of a sand bank under a sand wave field using the numerical model Delft3D. First, the schematized model set-up (i.e. schematized bathymetry and simple tidal forcing) showed that the alteration of the tidal flow by a sand bank resulted in tide-averaged horizontal flow towards the top of the sand bank, causing the bidirectional migration of sand waves over the sand bank. Second, a case study was performed in which a more complex model set-up was used (bathymetry and tidal forcing identical to a study site in the North Sea where an offshore wind farm is developed). Here, the model results revealed migration directions comparable to field observations. The results open opportunities to explore modelling migration patterns of sand wave fields for offshore wind farm development in areas with complex bathymetric environments