The ocean is an enormous source of renewable energy which currently remains largely untapped. The energy in oceans has various forms, most often based on the motion of water, but also on differences in salinity and temperature. Wave energy is the most important contributor of ocean energy.

Wave energy is an appealing potential renewable and sustainable energy resource. Waves are defined as a vertical motion of the ocean surface, where a wave is the profile of the surface elevation between two successive downward zero-crossings of the average surface elevation. When the sun heats the ocean surface, temperature differences occur that create strong winds. These winds interact with the ocean surface causing a rippling of the surface that gradually increases in amplitude. This distortion of the average ocean surface is what is commonly known as waves.

Ocean waves primarily consist of wind-generated waves and can vary from ripples to heights of over 30 meters. Ocean waves generated by wind can travel for thousands of kilometers before reaching land while preserving most of their energy content over these large distances. Although ocean waves are especially visible on the ocean surface, the energy of a wave is contained in the trochoidal movement of all water particles that move. For ocean waves, there is still a movement of particles well below the ocean surface at a depth of approximately half of the wave length of a wave. The distribution between particle movement and depth is exponential, meaning that most energy is contained in the top part of an ocean wave, while the trochoidal motion and energy content decreases fast at lower depths from the surface. Almost 90% of the energy is contained within a depth of a quarter of the wavelength.

As soon as the bottom water particles start to interact with the seabed, the water particles are pushed upwards and the trochoidal motion becomes squeezed into a more horizontal motion. This process gradually decreases the wave energy content and, therefore, waves in shallow waters contain less energy than waves in deep ocean waters. Although waves that reach the shore often provide an impressive view, the energy content in these waves is but a fraction of ocean waves in deep waters.

Ocean waves contain energy up to a depth of one half of their wave length. When the bottom of the wave hits the ocean floater in the surge zone, the energy level of a wave is effectively lowered and the particle movement becomes more orientated in horizontal direction.