Development of a composite sea wall wave energy converter system

The cost-effective utilization of wave energy is still a major engineering challenge. Shoreline locations for Wave Energy Converters (WECs) offer lower wave energy densities when compared with offshore locations, but give significant advantages from the points of view of construction, maintenance and grid connection. This article provides a first analysis on the viability of a very low-head hydropower plant, in which waves accumulate water into a shoreline reservoir created by a steep detached ramp. The system is particularly suitable for micro-tidal environments such as the Mediterranean Sea and has the additional advantage of protecting shorelines, seawalls and coastal assets from wave action. Physical model tests, conducted with regular waves, have been used to get a preliminary estimate of the average water flux overtopping the ramp in a sea state; a novel low-head hydropower machine, developed at Southampton University, has been considered for the conversion of the hydraulic energy into electricity. The site of Porto Alabe, located along the West coast of Sardinia (Italy), has been chosen as a first case study. Based on the inshore wave climate, the layout of the ramp has been designed as a tradeoff between the needs of maximizing the energy production, providing the coastal area with an adequate protection and making the plant a desirable investment to either private or public players. The results are interesting both from a technical and an economic point of views and encourage a further deepening on the response of this kind of WEC.