Coastal Defence Integrating Wave-Energy-Based Desalination: A Case Study in Madagascar

Abstract

In arid, coastal cities, water demand is often met through large-scale desalination systems. However, the energy required to run desalination plants remains a drawback. Further, numerous low-density population areas lack not only fresh water availability, but in most of the cases electrical grid connection or any other energy source as well. The challenge, consequently, is to ensure adequate fresh water supplies at the lowest possible cost. The main objective of this work is to assess the freshwater production from a reverse osmosis desalination system powered by a wave energy converter, the Overtopping Breakwater for Wave Energy Conversion (OBREC). The desktop analysis is illustrated through a case study on the Fenoarivo Atsinanana coast, along north-eastern Madagascar. The novel aspect of the analysis method is the application of a specific numerical code calibrated using preliminary results from a two-year monitoring campaign of the first OBREC prototype in operation in Naples Harbour (Italy). Instead of dissipating the incoming wave energy, the system collects the overtopping water above the sea level and the potential energy is converted into electricity through low head turbines. Then, the flow will be driven towards the desalination system. This configuration seems like a promising opportunity for developing countries to meet their water supply needs while at the same time developing their renewable energy potential.

Crown Wall Modifications as Response to Wave Overtopping under a Future Sea Level Scenario: An Experimental Parametric Study for an Innovative Composite Seawall

“…The exploitation of energy from the sea though Wave Energy Converters (WECs) is increasingly catching on, and numerous technological solutions are renovating this field [2,3]. The idea to integrate WECs into traditional coastal structures is not recent, and lately, it is moving toward the highest level of research and development [4][5][6][7][8][9][10].…”

Lifecycle Environmental Impact Assessment of an Overtopping Wave Energy Converter Embedded in Breakwater Systems

“…The nominal power installed is about 3 kW. Based on ongoing monitoring campaign and numerical simulation by using a specifically-designed numerical model (OBRECsim, see Contestabile and Vicinanza, 2018), a 250 m pier in Naples is expected to generate more than 630 MWh/yr, corresponding to a wave-to-wire efficiency of 13.9%. The scenario simulated, take into account a new set of low head turbines, able to work with a wide spectrum of different incident wave conditions and water levels.…”

Performance Assessment of a Hybrid Wave Energy Converter Integrated into a Harbor Breakwater

“…Since wave energy represents a large and mainly untapped energy source [3], with a theoretical resource estimated at circa 2.1 TW [4], integrating wave energy converters (WECs) into seaports' breakwaters has gained increasing interest in the field of coastal engineering [5]. Aside from the inherent possibility of exploring a sustainable and renewable energy source capable of meeting a relevant part of ports' energy demand, several synergies can be explored, including cost sharing on construction, installation, maintenance and operation during its life-cycle [5,6], water desalination projects [7] and onshore grid connectivity, as well as reducing the volume of water that overtops the breakwater [8]. This is further justified by mitigating the adverse impact of port activities, namely pollution, which has a very negative social and health impact as well as undesirable environmental consequences [9][10][11].…”