Numerical and experimental modelling for wave energy arrays optimization

Many wave power conversion devices, especially point-absorbers, do not provide alone the necessary amount of converted electricity to be cost effective, instead they are designed to be deployed in arrays of many units. Such arrays, or parks, can satisfy a large-scale energy demand, reduce the costs of the produced electricity and improve the reliability of the system. The performance of a wave energy park is affected by multiple and mutually interacting parameters, and the complex problem that arises during its design is called array optimization. The scope of the present thesis is to study such systems and their design, by the development of an optimization routine able to predict the best layout of a wave energy park under fixed constraints. The wave energy converter considered is the point-absorber developed at Uppsala University, which consists of a linear electric generator located on the seabed and a floating buoy at the surface. An optimization routine based on a genetic algorithm was created, which allows simultaneous optimization of the geometry of the buoys, the damping coefficient of the linear generators and the geometrical layout of the park. Finally, an experimental campaign with a single device and three arrays of six devices was conducted in order to compare the theoretical results with experimentally acquired data. The results identify optimal configurations of wave energy arrays, and highlight the effect of optimizing upon different objective functions, including economical ones. In the experiments, standard models and common assumptions used for wave energy park optimizations were tested against realistic conditions