Overtopping wave energy converters: applications and optimization of power capture

Among renewable energies, wave energy has a great potential and the technology behind the different concepts is reaching maturity and is able to full fill the requirements of reliability and power production.

Overtopping wave energy converters utilize the potential energy in the overtopping water of incoming waves: the water is stored in a number of reservoirs at a higher level then mean sea water level. In its natural way back to the sea, the water passes through turbines generating electricity.

One of the most important parameters in an overtopping device is the crest level at which the overtopping water is captured that is directly proportional to the stored power. The slopes leading to the reservoirs have to optimize the run up: a mild slope will generate breaking i.e. loss of energy while a too steep slope may represent an obstacle to storage. Other factors like orientation of the ramps toward the main wave direction, the draught of the run up rump and the overall dimensions of the device will influence the power capture.

The study proposed in this PhD thesis aims to find a standard method for defining the optimal setup for crest levels in overtopping devices in different locations and sea states and to detect the influence of a number of parameter on the hydraulic efficiency of such a wave energy converter. The study is supported by laboratory tests on performance of multilevel overtopping devices and numerical simulations.