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Sustainability 2016, 8, 1300 4 of 21

Mediterranean Sea, Ayat [22] in 2013 and Jadidoleslam et al. in 2016 [35] estimated values around
5 kW/m.

2.3. Performance Assessment of Wav Energy Converters
In order to evaluate the performance of wave energy converters, the commonly used methodology
is based on the so-called scatter diagram of the wave resource and the power matrix of the WEC.
The scatter diagram represents the occurrence of sea state as a function of the significant wave heights
and energetic periods [30,33] while the power matrix gives the related power output from the specific
WEC. The frequency of occurrence of the sea states with the highest wave power is generally very
scarce and does not contribute much to the total energy. However, their consideration is essential in the
investigation of WECs reliability and survivability [36]. The performance of a WEC is often evaluated in
terms of yearly mean values of power output, energy production or as the ratio between energy production
and the rated power of the WEC, the so called: capacity factor [38]. Following the latter methodology,
many studies [38–45] compared the performances of different devices in the same site of interest.
O’Connor et al. [39] estimated the performance of the Pelamis and Wavestar devices, with different
ratings of the devices, at six sites in Europe. The results of this study indicate that the Pelamis is
appropriate for the highest energetic sites, while the Wavestar is suitable for all sites. The capacity
factor of the Pelamis, the Wave Dragon and the AquaBuoy were obtained by Aoun et al. [40] on
the Lebanon coast, Dunnet and Wallace [41] on the east coast of Canada, Bozzi et al. [38] on the
Italian coast and Sierra et al. [18] on Menorca. These studies pointed out that for the Lebanon coast
the capacity factors of all the three WECs is extremely low (around 5%). The Wave Dragon device
operated with the highest efficiency, in the five analyzed areas in Canada with capacity factor larger
than 20% while the same device has a capacity factor around 10% when tested in the Mediterranean
area facing the Menorca coast. The Pelamis has the larger capacity factor (around 20%) in Alghero and
Mazara del Vallo sites in Italy [38]. Mota and Pinto [42] estimated on the western coast of Portugal
that the Wave Dragon has a capacity factor over 33% while the Pelamis and AWS have a capacity
factor below 15%. In 2015, Iuppa et al. [43] compared the performance of three nearshore devices
(Bref-SHB, B-HBA, B-OF) and seven offshore devices (F-2HB, F-HBA, F-3OF, F-OWC, AquaBuoy,
Pelamis, and Wave Dragon). The results show a maximum capacity factor lower than 4% in two
nearshore points selected on the western coast of Sicily. The Pelamis has the maximum capacity
factor (7.15%) on an offshore point closed to Marettimo Island. The performance of Wave Dragon,
Pontoon, OE, Wave Star, AWS, Wave Bob, Pelamis, Oceantec, Ceto, and AquaBuoy were tested by
Rusu. and Onea [44] on the European continental coast and by Rusu and Onea [45] on the European
coasts. The Sea Power and the SeabasedAB devices were also analyzed on the European coasts by
Rusu and Onea [45]. In the first paper the European continental coast are divided in four zones
(Northern Europe, Ireland and UK coasts, SW Europe, Mediterranean Sea and Black Sea. The Pontoon
has the best capacity factor (values between 5.84% and 14.5%) on the Mediterranean Sea and Black Sea
areas, while the Oceantec in the other areas. Rusu and Onea [45] analyzed the Iceland, Azores Islands,
Madeira Archipelago and Canary Islands. The performance analyses divided the WEC system in
two groups (device with rated power above 2470 kW and device with rated power below 1000 kW).
In the first group the Wave Dragon has the larger capacity factor (values between 19.3% and 33.4%).
Smaller differences are noticed at the second WEC group, with the exception of Ceto.

3. Materials and Methods

3.1. Assessment of the Offshore Potential
The present part of the study is based on numerical modeling wave hindcasting. The used wave
hindcasting was provided by IFREMER (French Research Institute for Exploitation of the Sea) and
was performed by the Prévimer model called MED 6MIN from June 2009 to December 2013, with a
◦
three-hour frequency [46]. The domain of wave hindcasting is the Mediterranean Sea from 6 W to