Wave energy conversion is still at the prototype stage, and there is no consensus on the most promising configuration. As a result, over a hundred different devices are being developed in more than thirty countries. The progress and future commercial success of each device depend on the technology being proven, reliable, and economically viable. In Italy, there is also a growing interest in the technological development of this sector, despite the fact that wave energy resources in the Mediterranean are generally lower compared to open seas and oceans. This creates significant challenges and opportunities, such as the development of cost-effective devices, the specialization of devices to match the characteristics of resources in Mediterranean sites, and the use of coastal infrastructure for installation. In this context, the WaveSAX device, a Wave Energy Converter of the Oscillating Water Column type, was conceived and developed by RSE in previous years of research.

The report presents research activities aimed at optimizing the energy production of the WaveSAX device through numerical studies, wave measurements, and experimental sea trials.

The computational fluid dynamics (CFD) study, conducted using ANSYS-CFX v.15.0, aims to identify improvements that enhance energy conversion efficiency by simulating rotors with different numbers of blades and considering the external domain, namely the sea surrounding the device. The configuration with seven blades demonstrated the best performance among those analyzed.

The assessment and understanding of the wave energy resource is essential for promoting the development and implementation of new electricity conversion technologies. Wave measurements, using a system consisting of a Barnacle and ADP-1.0MHz installed off the coast of Civitavecchia, aim to measure wave parameters along with current velocity, thus extending the historical data series that began in 2014. Finally, 1:5 scale experimental sea trials of the WaveSAX device and their subsequent analysis, with an evaluation of producibility under real wave conditions, identified the best control strategies for optimizing the electrical output of the WaveSAX. Additionally, the power matrix was developed, and the nominal power suitable for the local wave climate was assessed.