Wave Power

Wave power is the energy of the ocean waves what can be captured and used to generate electricity or pump water.  Waves are created from the sun heating the earth’s surface causing wind which dives waves. The north and south temperate zones where westerlies in these zones blow the strongest create the largest waves.  Larger waves are best for generating power.  The power is determined by the water density, wave speed, wave length and wave height.  Wave motion is best captured at the surface.  Motion is diminished the deeper you go below the surface. 

The strongest waves are on seacoasts that are on the receiving end of waves driven by wind crossing large areas of the ocean.  Winds traveling across the North Atlantic to the west coast of Europe are full of power.  Strong waves can be found in the U.S. northwest and northeast coasts, southern Africa, west coast of Scotland, northern Canada and Australia. 

Currently only a few experimental sites are in existence.  Ocean waves offer a vast energy renewable reserve.  If technology being used today was utilized for power generation 16% of the world electricity could be produced from wave power devices.  That would equal to 2,000 terawatt hours annually equal to the world’s largest hydroelectric plants produce. 

There are challenges when converting the kinetic energy produced by waves into electricity.  Devices must resist saltwater corrosion and be built to survive strong sea storms.  Low cost devices must be produced to competitively produce electricity. 

A device calls the Salter’s Edinburgh Duck is a cam like body that convert 90% of the wave motion into electricity.  The Duck is one of the most efficient devices tested.  The Duck has not been sea tested and its complex hydraulic system is not well suited for harsh conditions found at sea. 

Wavegen’s Limpet plant uses an oscillating water column to turn wave energy to electricity.  This device traps waves at the shore in a submerged cavern with a hole leading above the water line.  A wave entering the cavern will push air though the hole which spins turbine blades.  As the waver flows out of the cavern the turbine blades are designed to turn the same way.  This way electricity is generated with an incoming wave and out going wave.

A floating tube called Pelamis is a long hinged tube the size of five railway carriages.  The tube moves up and down in the waves and as the tubes bend at the hinges they pump hydraulic fluid which drive generators.

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