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Regions with long coastlines and archipelagos with numerous island communities, like the Mediterranean basin and the Aegean Sea respectively, are typically used as summer vacation destinations. In the summer months when the phenomenon is at its peak, this results in high electrical energy demand, which can be several times higher than the rest of the year. Furthermore, islands usually are not connected to the mainland power grid as such a connection may not be cost effective. Power supply for these regions is based on the installation of thermal electricity plants, using expensive and environmentally harmful fossil fuels. Over the last decades, “Green Islands” have been promoted through several projects where the demand is partly covered by Renewable Energy Systems (RES) relying on wind and solar energy which exists in abundance in the Southern Europe and especially in the Greek islands of the Aegean Sea (Hatziargyriou, 2012; ISET, 2008; Degner, 2004; Tselepis, 2003). However, the inherently intermittent operation of these power plants requires the standby operation of the old thermoelectric plants and poses stability and power quality challenges to the local grid.
As it is stated in the 2010 report ‘Rethinking 2050’ (EREC, 2010), the predicted contribution of bioenergy, geothermal, solar thermal and ocean energy, towards covering the energy demand in the next decades, is steadily increasing while the most conventional RES, hydro, wind and solar power are tending to the plateau of their potential. Tidal energy features among the proposed forms of ocean energy and its untapped potential increasingly attracts the interest of researchers, developers and investors (Hagerman & Polagye, 2006; Ray, 2000; Denny, 2009; Triton Consultants Ltd, 2002; Tidal Energy Ltd., 2009).
The most appealing feature of tidal energy is its inherent predictability which may counter the intermittent operation of solar or wind energy. Tidal power plants have already been established in Northern Europe where the strong tidal currents of the Atlantic Ocean are exploited (Tidal Energy, 2009; Hagerman & Polagye, 2006; Melton, 2012). Grid connected tidal plants in the Netherlands, Norway, Scotland, France etc. are using tidal barrages or turbines to produce electricity. The existing technology is therefore optimized for the strong tides of the north, and turbine manufacturers target the development of big turbines used in tidal barrages or deployed in farms, tied to the grid and producing energy up to several MW.