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CONCEPT

The basic strategy employed by the WavePiston concept is to convert the horizontal component of the oscillating movement of ocean waves into usable energy. Contrary to popular belief, an object floating in the ocean surface will not merely move in a vertical direction; the object will make a rotating movement as depicted in the animation above. Thus, in a wave there is a vertical as well as an equal horizontal movement, both having the potential for extracting usable energy. The magnitude of the rotating movement decreases with depth. The decreasing movement of waves with depth is well understood and is easily described using Airy’s wave equations. Although decreasing with depth, the motion of all water particles near the surface are largely moving in parallel. Hence, a vertical plate immersed in the sea will be subjected to a pure horizontal force trying to shift the plate from side to side. When a multitude of plates are immersed in the sea they will all be subjected to a different load due to the stochastic nature of ocean waves. Depending on the phase of the waves acting on the individual plates the force will either be in the direction of the waves or against the direction of the waves. Thus, the sum of the forces acting on all plates will be relatively small as the force on counter-moving plates will tend to cancel each other out. The defining feature of the WavePiston concept is to harvest energy along a string mounted with numerous vertical plates, said string having a length larger than a typical wave length. The energy is harvested by shunting energy from the horizontally moving plates, said plates energized by the horizontal component of the oscillatory wave movement.
Due to the stochastic nature of the ocean waves acting on each plate the forces on the individual plates will tend to cancel each other out with the net result that even very long WavePiston systems can be moored using only moderate means, thus making the WavePiston system relatively cost-efficient to install.