Comparison of Mooring Solutions and Array Systems for Point Absorbing Wave Energy Devices

Most of the ocean energy technologies are considered to be in a pre-commercial phase and need technical development. This study focuses on design of mooring solutions and compares array systems of a specific floating point-absorbing wave energy converter (WEC) developed by the company Waves4Power. A full-scale prototype of the WEC is installed in Runde (Norway) where it is moored with three polyester mooring lines, each having one floater and one gravity anchor. Based on this reference installation, the method of systems engineering was used to propose twenty-two conceptual mooring solutions for different array systems. They were compared and reduced to four top concepts in a systematic elimination procedure using Pugh and Kesselring matrices. The top concepts were assessed in detail by means of LCOE (levelised cost of energy), LCA (life cycle analysis) and risk analyses. The fatigue life of the mooring lines and the energy capture were calculated using results obtained from coupled hydrodynamic and structure response analyses in the DNV-GL DeepC software. Two final concepts were proposed for the water depths 75 and 200 m.