Design of a reinforced concrete Wave Energy Converter in extreme wave conditions

In the last decades, the growth of renewable energies showed to be more cost competitive, although traditional fossil fuels are still more affordable. Among the renewable energies, one of the most promising is wave energy, thanks to the high energy density stored in the waves. However, this precious resource requires further development, in particular to identify convenient and reliable production processes for conversion devices, known as Wave Energy Converters (WECs), and a view toward future changes and improvements of the existing prototypes. An interesting method to reduce the technological costs of energy and its environmental footprint could be found in the use of concrete structures, as opposed to traditional steel ones. This paper investigates the use of reinforced concrete for PeWEC, a floating wave energy converter, which converts wave energy into electrical energy thanks to its pitch motion. A preliminary design is carried out; pressure and mooring forces are evaluated and their structural effects are calculated by means of a finite element analysis. The design of reinforcements in a concrete shell is then reviewed. The general procedure is applicable to the case of a shell subjected to both bending and membrane stresses.