A Simple Model to Assess the Performance of an Overtopping Wave Energy Converter Embedded in a Port Breakwater

Luca Cavallaro,Federico Castiglione,Enrico Foti,Rosaria Ester Musumeci,Claudio Iuppa

doi:10.3390/jmse8110858

Luca Cavallaro, Federico Castiglione + Show 3 more

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https://doi.org/10.3390/jmse8110858

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Abstract

A numerical model for the optimization of the performance of an innovative overtopping breakwater for wave energy conversion is proposed. The model is based on the stochastic description of the overtopping phenomenon based on the results of extensive laboratory tests, and it is able to simulate the behavior of the device operating under any assigned sequence of sea states, thus allowing to easily obtain results that would otherwise require time consuming and costly physical model tests. The model is used here to identify the main geometrical parameters affecting the performance of the device and to optimize such parameters in order to maximize the average yearly output power. An application to a device embedded in the breakwater of Pantelleria Port (Sicily, Italy) is presented. The model is also proved to be useful to verify the possibility of further increasing the output power through the implementation of specific control strategies concerning the operation of the turbines. The work provides a better understanding of the influence that such a system could have on the energy system of small Mediterranean islands, for example in terms of contribution to the CO2 emission reduction.

Highlights

Ocean tides and waves represent an exceptionally large and untapped source of energy which could be efficiently exploited, together with the most common renewable sources of energy, to achieve a more sustainable world energy system (IEA-OES [1]).Nowadays the installation and maintenance costs of the Wave Energy Converters (WECs) are high compared to other renewable sources of energy
In other to reduce these costs, WECs can be embedded in port breakwater and two main technologies of these devise exist: the Oscillating Water Column (OWC) and the Overtopping BReakwater for Energy Conversion (OBREC)
In order to estimate the performance of an OBREC device, whose main geometrical parameters are described in Figure 1, in the present paper the energy produced by the device was estimated through two steps

Summary

Introduction

Ocean tides and waves represent an exceptionally large and untapped source of energy which could be efficiently exploited, together with the most common renewable sources of energy (i.e., solar and wind power), to achieve a more sustainable world energy system (IEA-OES [1]).Nowadays the installation and maintenance costs of the Wave Energy Converters (WECs) are high compared to other renewable sources of energy. In other to reduce these costs, WECs can be embedded in port breakwater and two main technologies of these devise exist: the Oscillating Water Column (OWC) and the Overtopping BReakwater for Energy Conversion (OBREC). The present work concentrates on the Overtopping BReakwater for Energy Conversion (OBREC) Such a device has been designed to extract energy from the overtopping process which occurs at harbour rubble mound breakwaters. It consists of a concrete frontal ramp that reduces the friction of the breakwater and facilitates the overtopping of the waves into a reservoir located above sea level; the water flows back to the sea through one or more low-head turbines [4,5,6]

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