Experimental investigation on a novel and hyper-efficient oscillating water column wave energy converter coupled with a parabolic breakwater.

Ocean wave energy is a rapidly developing sector and has the potential to contribute a significant share to the global green energy transformation. However, nearshore coastal regions, in which energy harvesting devices are most commonly installed, experience low wave energy densities compared with offshore regions. This is a significant impediment to the commercialisation of the wave energy sector. This study proposes a low cost solution to these low wave energy density distributions at nearshore environments whilst simultaneously providing an effective coastal protection system. A parabolic energy concentrator wall is coupled with an oscillating water column wave energy converter. The parabolic concentrator reflects and consolidates the incident wave energy to a focal point, at which the wave energy convertor is positioned. Experimental investigations, supported by numerical modelling results confirm energy conversion performances significantly exceeding hitherto recorded wave energy converter efficiencies, with wave-to-wire conversion efficiency in the laboratory model exceeding 70%. Furthermore, the parabolic concentrator wall has an ancillary purpose to act as a shoreline protection barrier. The simplicity of design, high energy conversion efficiencies, and inherent shoreline defensive aspect of the proposed system deems it particularly suitable for deployment to remote island nations, or coastal communities vulnerable to coastal erosion that presently rely on fossil fuel consumption for energy generation. • A novel OWC WEC-parabola-breakwater system is developed. • The parabolic breakwater focusses the wave energy to the OWC WEC. • Physical experiments are supported by compressible numerical modelling. • The system achieves capture-width-ratios exceeding 2.0. • Wave-to-wire efficiencies of 0.7 are revealed. [ABSTRACT FROM AUTHOR]