Power capture performance of hybrid wave farms combining different wave energy conversion technologies: The H-factor

In this paper we consider hybrid wave farms, in which different types of WEC are combined, through a case study involving oscillating water columns (OWCs) and point-absorbers (PAs). A new parameter, called “H-factor”, is introduced to compare hybrid (multi-type) and conventional (single-type) wave farms in terms of wave power capture. We develop an ad hoc semi-analytical model to calculate the H-factor in a computationally efficient manner, and apply it to investigate how the H-factor and, consequently, the power capture, depend on: (i) the spacing and layout of the WECs, (ii) the type of WEC technology, and (iii) the wave conditions. We discuss the influence of these factors and, in the process, show that the H-factor is a valuable decision-aid tool. For specified wave conditions and layout limitations, a conventional wave farm may not be the most efficient option as a result of a destructive array effect, whereas a hybrid farm can be more efficient if a constructive hybrid effect occurs (if the H-factor value is above unity). This constructive hybrid effect can even overcome the destructive array effect for specified cases, demonstrating the potential advantage of hybrid wave farms relative to conventional wave farms.