My contribution to the 16th European Wave and Tidal Energy Conference is a paper considering how the placement of wave energy converters (WECs) within WEC arrays can contribute to lower cost hydraulic power-trains. Here is the abstract:

The construction of densely spaced wave energy converter (WEC) arrays is recognized as being important for utility-scale wave energy conversion. One advantage that has been noted for WEC arrays is reduced output power variation resulting from the superposition of the otherwise highly variable outputs of each device, especially for a large number of WECs. This advantage addresses an important design trade-off between produced power and installed energy storage capacity, which emerges from the physical limits of powertrain hardware and constraints on the quality of delivered electrical power.

This work proposes that the advantage of smoother output power can also be realized in the design performance of hydraulic power take-offs (PTOs), in addition to the benefits previously noted for downstream electric hardware. Specifically, we consider a scheme in which individual WECs share a common hydraulic circuit that aggregates the flow contributions of each WEC-driven pump. Additionally, we explore the effect of deliberately positioning the WECs out of phase with respect to incoming wave excitation. The impact of these strategies is evaluated through simulation for a near-shore environment. Results show significant improvements to the Pareto front describing the trade-off between generated power and installed energy storage, even with as few as two WECs sharing a single hydraulic PTO circuit.

There are a few details to work through.

I see this as being a solution that is only appropriate for the nearshore environment where the waves are traveling predominately in a single direction, in contrast to the deep sea where waves can be traveling in all directions. We see waves traveling in a single direction in the nearshore environment because of the effect that the ocean depth has on the wave speed. As the depth of the ocean shrinks when moving toward shore, the wave speed decreases. Consequently, waves traveling at an off-angle from shore will “turn” toward shore. This change in direction is know as refraction and is the same mechanism that causes light to bend when it passes through a prism.