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Sustainability 2016, 8, 1300 17 of 21

Italian potentials than the EU oceanic site potentials. On the basis of this analysis, Table 6 summarizes
the most suited offshore and nearshore WECs, among those tested, for each studied Italian sites.

Table 6. The most suited WECs for each Italian sites.

Location Offshore WEC Nearshore WEC
Tuscany Wave Dragon Wave Star
Liguria Wave Dragon Wave Star
Sardinia Pelamis Wave Star
Sicily Pelamis Wave Star

6. Conclusions
The assessment of wave energy potential in the offshore of the whole Mediterranean Sea confirms
that the most energetic offshore area is located between Corsica, Sardinia and Balearic Islands. In this
area, the maximum yearly mean wave power reaches 16.4 kW/m. This assessment was carried
out using a numerical simulation hindcasted period substantially lower than those used in 2013 by
Liberti et al. [17] and in 2016 by Besio et al. [19], nevertheless their values of the maximum yearly
mean power in this area are equal to our value. This potential is related to an offshore area that is too
far from the continental borders and so, in practice, the interest for its exploitation is lowered due to
unfavorable economic reasons.
In general, a favorable condition that can facilitate the exploitation of wave energy potentials is
the proximity of a harbor and coastal sites where the produced energy can be transferred and used.
Such condition can lower the maintenance, monitoring, and energy transport costs. It is why an
assessment was performed of the nearshore potentials in front of the Tuscany, Liguria, Sardinia and
Sicily regions. This nearshore assessment also permitted the location of hotspots, i.e., the areas where
the wave power has the maximum value in their surroundings and, sometime, the local wave power is
also higher than the offshore values. The Liguria hotspot is just 1 km from the closer harbor while it is
10 km for the Sicily and Tuscany hotspots and 40 km for Sardinia hotspot.
Among all the four hotspots of this work, the most energetic is the one near the headlands of
the Argenteria (Sardinia region) on water depth of 20 m where the total mean annual energy reaches
100 MWh/m. The second most energetic hotspot is located NW of the Marettimo Island in front
of Punta Mugnone (Sicily region) in 15 m of water depth where the total mean annual energy is
80 MWh/m and the wave conditions with 7 s < T m−1,0 < 8 s and 2 m < H m0 < 3 m is responsible of the
major contribution equal to 4.7 MWh/m. The Tuscany hotspot is located at the Meloria shoals in water
depth of 10 m where the wave conditions 7 s < T m−1,0 < 8 s and 2 m < H m0 < 3 m bring most of the
energy for a contribution of 2.9 MWh/m while the total mean annual value reaches 41 MWh/m. In the
case of the Liguria area, the hotspot is located in front of Monaco at a water depth of 10 m, the total
annual energy reaches the very limited value of 18 MWh/m and most of the energy is carried by wave
conditions 5 s < T m−1,0 < 6.5 s and 1 m < H m0 < 1.5 m that account for 2 MWh/m.
The performance assessment of the state of the art WECs, here investigated, demonstrates that
the offshore devices most suited for the Italian areas, in terms of capacity factor when installed in
50 m water depth, are the Wave Dragon for the Tuscany and Liguria and the Pelamis for Sardinia and
Sicily. However, in each studied offshore site, the highest mean power output as well as the maximum
capture width is always guaranteed by the Wave Dragon. In the case of the hotspots, the most suited
device is always the Wave Star in terms of higher values of capacity factor, capture width and mean
power output and, moreover, the highest capture width is obtained in the case of Tuscany area.
The comparison between the performance estimates of the studied WECs, in the most energetic
oceanic site here considered (i.e., the Azores Island) and in the Italian sites, demonstrated that the
capacity factor in the Italian sites is always lower than those obtained in the ocean, as expected,
since all the devices are developed for the oceanic wave climate. However, the capture width values
in the Italian sites are larger than those obtained in the Azores except for the AWS device in the