An analysis of wave energy along the coasts of Sicily (Italy) is presented with the aim of selecting possible sites for the implementation of wave energy converters (WECs). The analysis focuses on the selection of hotspot areas of energy concentration. A third-generation model was adopted to reconstruct the wave data along the coast over a period of 14 years. The reconstruction was performed using the wave and wind data from the European Centre for Medium-Range Weather Forecasts. The analysis of wave energy allowed us to characterise the most energetic zones, which are located on the western side of Sicily and on the Strait of Sicily. Moreover, the estimate of the annual wave power on the entire computational domain identified eight interesting sites. The main features of the sites include relatively high wave energy and proximity to the coast, which makes them possible sites for the implementation of WEC farms.

The performance of several Wave Energy Converter devices is evaluated at three sites located on the west side of Sicily. To select the most energetic site, the average potential wave energy along the coasts of Sicily is evaluated by adopting a third-generation spectral wave propagation model using as boundary conditions the European Centre for Medium-Range Weather Forecasts operational archive wave and wind data. The most energetic sites are on the western side of Sicily. In the three hotspots identified, the mean energy flux is within the range of 5.33–7.52 kW/m. The analysis shows that all considered devices have a low capacity factor in their original configurations (2.19%–5.12%). The main causes of the poor results in terms of energy production are related to the fact that such devices are optimized for high-energy waves. A resizing of the devices on the basis of the local wave climate showed that a capacity factor that exceeds 30% could be obtained.

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).

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.