The Mocean wave energy converter (WEC) is a hinged raft device. The dynamic response of the raft’s two bodies to wave forcing leads to a flexing motion about the hinge, which drives a power take-off mechanism that converts the kinetic energy into electricity.
The innovation of the Mocean WEC is in the design of the shapes of the bodies, which dramatically improves its dynamics and thus power absorption. The configurations are based around varying the ratio and position of the water-plane area to the submerged volume, where the water-plane area affects the hydrostatic restoring force and the volume affects the mass and added mass. By changing these values one can induce coupling between the modes of motion and so tune the resonant response to improve performance in wavelengths that are significantly longer than the overall length of the machine.
The component bodies are designed to be hydrodynamically quite dissimilar. Consequently, although the power take-off is solely in flex around the hinge, there is extensive cross-coupling with other degrees of freedom, and when excited by wave action the device responds not only in flex but substantially in heave and also pitch and surge. This results in greater cancellation of the incoming wave and a broader bandwidth response than a standard hinged raft.