Assessing the Performance of Arrays of Two Body Hinged Attenuator WECS

Abstract

Ocean renewable energy is a key enabler of the global transition toward a decarbonised and resilient energy system. Among marine resources, wave energy offers high energy density, predictability, and strong complementarity with offshore wind, making it a promising candidate for reliable power generation. Despite this potential, commercial deployment remains limited due to challenges related to efficiency, survivability, and cost. As a result, research has increasingly shifted from individual devices to wave energy arrays, where hydrodynamic interactions can play a critical role in enhancing overall performance.
Two-body raft-type attenuators, such as the designs of the wave energy converters of Mocean Energy, have emerged as a promising configuration for intermediate to deep waters. These devices consist of two floating sections connected by a hinge joint, with energy extracted from their relative rotation through a power take-off (PTO) system. While the hydrodynamics and control of single raft devices have been studied, array-scale analyses of such hinged attenuators remain scarce, particularly those incorporating explicit PTO modelling. This gap limits current understanding of how inter-device hydrodynamic coupling influences array performance. This study presents a systematic assessment of arrays of two-body hinged raft attenuators using a weakly nonlinear frequency-domain model implemented in the open-source BIEM solver HAMS-MREL. The solver resolves multi-body diffraction and radiation interactions while explicitly representing hinge dynamics through frequency-dependent PTO damping and stiffness. A range of array configurations is analysed, varying the number of devices, spacing, and layout. Array performance is quantified solely using the array interaction factor (q-factor), enabling direct assessment of constructive and destructive hydrodynamic interactions. The results provide new insight into the role of array configuration and PTO characteristics in governing performance and highlight the potential for power amplification through favourable wave–device interactions.