Numerical Modelling of Wave Energy Converters
Introduction In the last century, research into renewable energy resources became more and more important. Where wind and solar energy are already commercially viable, wave energy is a rather new, but promising development. The power within ocean waves is dense, can efficiently travel long distances and is sufficient to contribute significantly to the energy market. Wave energy from ocean waves is absorbed by using Wave Energy Converters (WECs). WEC development is characterised by a large
... y of device types; differentiation is made based on the location, device geometry, mooring type and operating method. In this research, focus is put on wave activated bodies. These are floating devices, located nearshore or offshore, producing energy directly from their own kinetic and potential energy, in response to the incoming waves. In order to extract a considerable amount of wave power at a location in a cost-effective way, large numbers of WECs are arranged in farms using a particular geometrical configuration. Interactions between the individual WECs (near field effects) affect the overall power production of the farm. In response to an incoming wave, a floating body starts moving in six degrees of freedom. As a consequence, the device itself starts creating waves, called radiated waves. Additionally, because of the presence of a structure in the wave field, the incoming waves are partially reflected and diffracted. The total wave field around a WEC is thus a combination of incoming, radiated, reflected and diffracted waves. This results into zones with higher wave elevations and zones with lower wave elevations compared to the incident wave field. One should thus avoid that one WEC is positioned in the wake region of another WEC. By arranging the WEC park layout with the individual WECs positioned in zones with amplified wave elevations, the total power production can be significantly higher. In combination with these near field effects, the installation of a WEC park also influences the wave climate further away (far field effects). The wave height reduction behind an entire WEC farm affects other users in the sea, the environment or even the coastline. When installed close enough to the shoreline, a WEC farm can be used as a first-line coastal defence mechanism.