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Overtopping-type wave power conversion devices represent one of the most promising technology to combine reliability and competitively priced electricity supplies from waves. While satisfactory hydraulic and structural performance have been achieved, the selection of the hydraulic turbines and their regulation is a complex process due to the very low head and a variable flow rate in the overtopping breakwater set-ups. Based on the experience acquired on the first Overtopping BReakwater for Energy Conversion (OBREC) prototype, operating since 2016, an activity has been carried out to select the most appropriate turbine dimension and control strategy for such applications. An example of this multivariable approach is provided and illustrated through a case study in the San Antonio Port, along the central coast of Chile. In this site the deployment of a breakwater equipped with OBREC modules is specifically investigated. Axial-flow turbines of different runner diameter are compared, proposing the optimal ramp height and turbine control strategy for maximizing system energy production. The energy production ranges from 20.5 MWh/y for the smallest runner diameter to a maximum of 34.8 MWh/y for the largest runner diameter.

The OBREC is an overtopping structure which is integrated into a traditional rubble-mound breakwater to convert wave energy into electricity. The relatively simple geometry of this overtopping device, with a single frontal ramp and a reservoir, makes the technology suitable to be fully combined also with existing structures. OBREC has been deeply investigated over the last years with physical and numerical model tests, and it is still under development with the ongoing monitoring activities at full-scale in real environments focusing on the wave-OBREC interaction. A comprehensive review of the research studies during the last ten years is here presented. The paper contains some unpublished details on OBREC geometry and power take-off strategy. A special attention is also directed to the description of the full-scale prototype of OBREC at Naples harbour, where an experimental campaign is still continuing.

The aim of this work is to analyze the performance of the Overtopping Breakwater for Energy Conversion (OBREC), developed by the team of the University of Campania and installed at prototype scale in the port of Naples. It is a multifunctional coastal structure aimed to protect harbors and produce energy, based on the overtopping principle. This device has been preliminary analyzed by means of experimental and numerical investigations. This contribution provides for the first time an integrated assessment of the OBREC hydraulic and structural performance, by means of the measurements collected at the prototype installation and of numerical modelling i.e. methodologies not affected by the scale effects. The numerical model, developed in the openFOAM environment, is calibrated on the field data gathered during a storm event and is then applied to extend the information related to the OBREC response under the typical wave climate. The results obtained are proposed in terms of overtopping discharge rates and pressures acting along the OBREC profile, under several sea states. Based on these results some recommendations and indications regarding the optimal cross section design are given to maximize the energy production, without compromising the structural stability, and to promote the device exploitability.

OBREC is the acronym that stands for Overtopping Breakwater for Energy Conversion. It is a multifunctional device aimed to produce energy from the waves, while keeping the harbour area protected from flooding. In this paper, the inclusions of a berm to reduce wave reflection, the shape of the sloping plate to maximise wave overtopping and the reservoir width and the crown wall shape to maximise wave energy capture while keeping the harbour safety were analysed to optimize the hydraulic and structural performances of the device. Several configurations were numerically investigated by means of a 2DV RANS-VOF code to extend the results already obtained during previous experimental campaigns. The wave reflection coefficient, the average wave overtopping flows and the wave loadings along the structure are computed, compared with existing formulae and discussed with reference to the OBREC prototype installed in the Port of Naples.

Brazil has one of the largest electricity markets in South America, which needs to add 6000 MW of capacity every year in order to satisfy growing the demand from an increasing and more prosperous population. Apart from biomass, no other renewable energy sources, besides hydroelectricity, play a relevant role in the energy mix. The potential for wind and wave energy is very large. Brazil's Santa Catarina state government is starting a clean energy program in the state, which is expected to bring more than 1 GW of capacity. Assessment of wave energy resources is needed along the coastline. This work studied the potential wave energy along the north-central coasts of Santa Catarina, in Southern Brazil, by analysis of the hindcast data from the European Centre for Medium-Range Weather Forecasts (ECMWF). The annual offshore wave power was found to be equal to 15.25 kW/m, the bulk of which is provided by southeastern waves. The nearshore energetic patterns were studied by means of a numerical coastal propagation model (Mike21 SW). The mean wave power of 20 m isobaths is 11.43 kW/m. Supplementary considerations are drawn on realistic perspectives for wave energy converters installations.

This paper describes a set of spectral and eigen analysis in order to identify seiche generation from a large-scale laboratory dataset. The experiments were performed in the large-scale &ldquo, Canal d&rsquo, Investigaci&oacute, i Experimentaci&oacute, Mar&iacute, tima&rdquo, wave flume at the Universitat Polit&egrave, cnica de Catalunya in Spain. Erosive and accretive wave regimes have been analyzed, including monochromatic waves and bichromatic wave groups with different bandwidths. Each test started with approximately the same underlying beach conditions. Video runup measurements are also used to better understand the role of the bandwidth in the generation of swash oscillation. Some evidence of the influence of low frequency waves on runup and sediment transport pattern is found. Good agreements between eigenmode families for volume flux and sediment volume variations are also shown.

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.

The spread of the wind energy industry has caused the construction of wind farms in areas prone to high seismic activity. Accordingly, the analysis of wind turbine loading associated with earthquakes is of crucial importance for an accurate assessment of their structural safety. Within this topic, this paper presents some preliminary results of a probabilistic framework intended to be used for the estimation of the probability of failure of Horizontal Axis Wind Turbine-supporting structures when subjected to the wind and seismic actions. In particular, the multi-hazard fragility curves of the wind turbine-supporting structure were calculated using Monte Carlo simulations. A decoupling approach consisting of aerodynamic analysis of the rigid rotor blade model and subsequent linear dynamic Finite Element analyses of the supporting structure, including aerodynamic damping, was used. The failure condition of the tower structure was estimated according to the stress design procedure proposed by EC3 for the buckling limit state assessment. Finally, the vulnerability assessment of HAWTs to wind and seismic actions was evaluated in terms of fragility curves describing the probability of failure of the supporting tower structure as a function of the Peak Ground Acceleration (PGA) for each parked and operational wind condition. In particular, the results highlight a probability of failure larger than 50% for high levels of seismic action (PGA greater than 0.7 g) combined with the rotor in parked condition (wind speed of 3 m/s) or in operational rated condition (wind speed of 11.4 m/s).

The Maldives are situated in the remote equatorial Indian Ocean, covering 900 km from north to south. The 26 coral atolls forming the archipelago are composed of sand and coral with a maximum height of about 2.30 m above the mean sea level. Periodic flooding from storm surges and the frequent freshwater scarcity are perceived by the population and the economic operators as the major environmental stresses. Moreover, the strong dependence on imported fossil fuels increases, even more, the environmental concerns. Diesel, in fact, still represents the main source of power generation, typically through privately managed small diesel sets. The real challenge for this area is to promote the environmental quality with socioeconomic growth. The present study aims to evaluate the strategic effectiveness to face these issues by wave and offshore wind energy. Resources using a 10-year hindcast dataset are here examined. The annual offshore wave power was found to range between 8.46 kW/m and 12.75 kW/m, while the 10 m and 100 m mean wind power density is respectively 0.08 kW/m2 and 0.16 kW/m2. Based on these results, an environmentally and socio-economically sustainable best-case scenario is constructed and two atoll islands (Malè and Magoodhoo) are specifically investigated. As a result, multifunctional structures and multi-use systems, which combine power generation, desalinization and coastal defence, are strongly recommended.

The Overtopping BReakwater for Energy Conversion (OBREC) is an overtopping type wave energy converter, totally embedded into traditional rubble mound breakwaters. The device consists of a reinforced concrete front reservoir designed with the aim of capturing the wave overtopping in order to produce electricity. The energy is extracted through low head turbines, using the difference between the water levels in the reservoir and the sea water level. This paper investigates the nature and magnitude of wave loadings exerting on various parts of the structure. The results improve the overall knowledge on the device behavior, completing the highlights from the complementary test campaign carried out in the same wave flume in 2012 (Vicinanza et al., 2014). The formulas provided have been used to design the first OBREC prototype breakwater in operation since January 2016 at Naples Harbour (Italy).

This paper constructs an optimal configuration assessment, in terms of the financial returns, of the Overtopping BReakwater for wave Energy Conversion (OBREC). This technology represents a hybrid wave energy harvester, totally embedded in traditional rubble mound breakwaters. Nine case studies along the southern coast of Western Australia have been analysed. The technique provides tips on how to estimate the quality of the investments, for benchmarking with different turbine strategy layouts and overlapping with the costs of traditional rubble mound breakwaters. Analyses of the offshore and nearshore wave climate have been studied by a high resolution coastal propagation model, forced with wave data from the European Centre for Medium-Range Weather Forecasts (ECMWF). Inshore wave conditions have been used to quantify the exploitable resources. It has been demonstrated that the optimal investment strategy is nonlinearly dependent on potential electricity production due to outer technical constraints. The work emphasizes the importance of integrating energy production predictions in an economic decision framework for prioritizing adaptation investments.

The Overtopping BReakwaterfor Energy Conversion (OBREC) is an overtopping wave energy converter, totally embedded in traditional rubble mound breakwaters. The device consists of a reinforced concrete front reservoir designed with the aim of capturing the wave overtopping in order to produce electricity. The energy is extracted through low head turbines, using the difference between the water levels in the reservoir and the sea water level. This paper analyzes the OBREC hydraulic performances based on physical 2D model tests carried out at Aalborg University (DK). The analysis of the results has led to an improvement in the overall knowledge of the device behavior, completing the main observations from the complementary tests campaign carried out in 2012 in the same wave flume. New prediction formula are presented for wave reflection, the overtopping rate inside the front reservoir and at the rear side of the structure. Such methods have been used to design the first OBREC prototype breakwater in operation since January 2016 at Naples Harbor (Italy).