ABSTRACT
The ocean waves are an important renewable energy resource that, if extensively exploited, may contribute significantly to the electrical energy supply of countries with coasts facing the ocean (Barstow et al. 2008). A wide variety of technologies has been proposed, studied, and in some cases tested at full size in real ocean conditions (Falnes 2007; Drew et al. 2009; Falcão 2010; López et al. 2013). The mechanical process of energy absorption from the waves requires a moving interface, involving (i) a partly or totally submerged moving body and/or (ii) a moving air-water interface subject to an oscillating pressure. In the latter case, there is a fixed or oscillating hollow structure, open to the sea below the water surface, that traps air above the inner free-surface; wave action alternately compresses and decompresses the trapped air which forces air to flow through a turbine coupled to a generator. Such a device is named oscillating-water-column (OWC). The main advantage of the OWC versus most other wave energy converters is its simplicity: the only moving part of the energy conversion mechanism is a turbine, located above water level, rotating at a relatively high velocity and directly driving a conventional electrical generator.
