Wave Energy

Wave energy is present across the globe and can be harnessed as a combination of kinetic and potential energy of water particles. Waves are created by the action of winds passing over the surface of the ocean. Wave heights (and thus energy) are greatest in the sub-equatorial regions where the trade winds (such as the 'Roaring Forties') are strong and blow consistently in the same direction over long distances (Fig. 26.1).

Fig. 26.1 Global distribution of annual mean wave power. (Cornett 2008)

Fig. 26.1 Global distribution of annual mean wave power. (Cornett 2008)

In addition to the geographic variability indicated by Fig. 26.1, there are also seasonal and shorter-term variabilities in wave regimes, brought about by weather systems. In the higher latitude areas, background wave regimes may be sufficient to permit almost continuous generation. Extreme wave conditions, brought about by storms, may provide greater energy than average conditions but this energy may not be extractable if wave energy devices have to go into 'survival' mode. Nonetheless, waves are essentially integrated wind energy, which are thus more predictable than winds. Wave energy farms may produce more forecastable energy, thus enabling project developers to secure higher prices for their produced power.

There are a number of computational wind wave models, which are used for wave forecasting (Greenslade and Tolman 2010).

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