Wave Power Calculator NZ

This calculator estimates the power carried by deep-water ocean waves per metre of wavefront, from the wave height and period, the key figure in assessing wave energy. The ocean's waves carry an enormous amount of energy, and harnessing even a fraction of it is a serious prospect for renewable generation, which makes quantifying wave power important for engineers, oceanographers and energy planners. For deep-water waves, the power transmitted per metre of wave crest depends on just two readily measured quantities: the significant wave height, a standard measure of the typical wave size in a sea state, and the wave period, the time between successive crests. Taller waves and longer periods both carry dramatically more power. This calculator computes it. You enter the significant wave height in metres and the wave period in seconds, and the calculator returns the wave power per metre of wavefront in kilowatts, the value in watts, and, if you provide a wavefront length, the total power across it. The results update as you type. Use it for oceanography and energy study, for assessing a wave energy resource, or to understand the scale of power in the sea. The power per metre is given by the standard deep-water formula: the density of seawater times gravity squared, divided by sixty-four pi, times the wave height squared times the period. Because the power depends on the square of the wave height, doubling the height quadruples the power, and it also rises in direct proportion to the period, so long-period swells from distant storms are especially energetic. Typical open-ocean conditions carry tens of kilowatts per metre, and energetic coastlines exposed to long swells, like parts of New Zealand's, are among the best wave-energy resources in the world. The formula applies to deep water, where the depth is more than about half the wavelength; in shallow water the relationship changes as waves interact with the seabed.

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Deep-water power per metre = (ρ g² / 64π) x height² x period, with seawater ρ = 1025 kg/m³. Power rises with height squared and with period. Deep water only.