Wave energy can be converted in many ways to harness/create household elecetricity. For example by the use of a wave energy generator.A generator like this is located at coastal areas like Washington,California,Oregon,other areas along North-Americas west coast,this also includdes the coasts of scotland,Africa and Australia.
The generator works in such a way that it uses the tidal energy of the waves which comes from the scattered solar energy, these waves are in the form of a rise and fall pattern which have massive kinetic energy.When these waves reach underwater systems like waterwheels and turbines they generate hydroelectricity or simply electricity.These systems can be the Tidal Barrage,Tidal stream or a hydroplane.All these systems are present within the depth of the water.
The tidal Barrage or the oscillating water Column (OWC) use the up and down moving water wave energy which moves a raft up and down,this raft transfers the wave water to pipes with holes which compresses and decompresses the air,this air has such a force that it creates a certain pressure within the turbine chamber which makes the wings of the turbine rotate.These turbines in turn produce electricity.The principle is exactly the same for a ‘tidal barrage’ except it’s turbines are rotated with the movement of water flow from the top of the shaft to the bottom of a canal chamber which contains turbines. The disadvantage of a ‘tidal barrage generator’ is that is can only be run during high and low tides generation when the the tide is stationary.Another disadvantage is the construction of this barrage because of it being a long concrete dam.Another systematic generator is a tidal stream generator,that consists of rotor blades below the water which produce electricity by there rotation which is caused by the tidal waves.
These generators operator just below the surface of the water unlike off-shore generators.The tidal streams that these generators use are which are produced on the shoreline.The advantage of a stream generator is that they produce a higher tip speed than wind generators,this causes this specific generators rotors to rotate faster and thus giving more output.The disadvantage of these generators is that as they are submerged below the water,they thereby create problems to navigation and shipping.There are also forms of tidal energy which result in a different rotor of a turbine,for e.
g vertical-axis turbines that are present within a fence.These turbines have hydroplanes,which are positioned on the seabed which rotate according this wave movement.Such turbines are like the flippers of a whale which oscillate according to these tidal waves.
Moreover the angle of the tide to the hydroplane can be increased to give a better output.There are certain advantages and disadvantages of tidal energy,some of them are;Advantages:(1)It is a renewable energy source as it is a natural energy source and requires no fuel.(2)It has the potential to produce green/clean energy.It is inexpensive in a way.
(3)Low visual impact as they are not totally submerged in the water like tidal turbines.(4)Low noise pollution.High predictability as high and low tides can be predicted easier than wind.(5)Tidal barrages provide protection again floods etc(6)Large reservoirs of tides can create lakes even in plane areas.Disadvantges:(1)Tida energy is not always a constant energy,as the tides also depend on the gravitational ull of the sun and the moon.
(2)Tidal energy requires an area where strong tides can be produced.(3)They can resist natural forces therefore the construction of strong structures like barrages can be costly.(4)Large distribution costs once the energy has been converted to hydro-electricity e.g long distant underground cables.
Also it generates limited power energy source i.e 10 hours per hour.(5)Erosion of coastal areas where large tides are present and changes in estuary ecosystems.(6)Build up of silt which are brought along with the streams that are flowing in the basin as they can not flow like that out in the sea.Danger to aquatic life as they can also get stuck in this barrage or sucked in by the barrages blades.Another modern electricity generator is the ‘Archimedes Wave Swing’ which has been introduced in scotland for the first time,it is a scottish craftwork.It is better than a barrage as it is a cylinder buoy moored to the seabed.
In this the tidal waves fill an upper casing against a lower fixed cylinder,hence creating electricity by this alternating movement. It is a “£13 million support package for Scottish marine energy developers funded by the Scottish Executive.”It is submerged at least six metres below the sea and has a 25metre height and 12 metre diameter and can generate 3000 Megawatt hour of electricity annually.It is similar to the energy produced by a large wind turbine which provides sufficient energy to about 300 houses.Also China is constructing a tidal lagoon power plant at the Yalu River, near its border with North Korea.This ‘Tidal lagoon’ is better than a large cement barrage i many respects.Such as it can be constructed by natural rock material.Also animals can swim around it and smaller animals can swim safely inside it without large predators being able to enter the lagoon.It will contain freshwater.The lagoon can be made with a low wall where the low tidal wall and a large wall submerged in the sea where the large tides will be present.There are two tidal situations i.e, spring tides (maximum ) and neap tides (minimal).Spring tides are produced when the moon and sun are in perfect alignment,this happens during a new or full moon phase.In these tides the high tides become very high compared to the low which become very low during each tidal cycle.On the other hand,Neap tides are produced when the gravitational pull of the sun and the moon are against each other thus producing weak waves but these changes can still help in electricity production.