We all know the power of the sea and a simple example can be seen in the way surfers use the power of the waves converted into forward motion but surfers also know how dangerous the enormous power can be.

The potential power contained in waves is huge and if we can convert some of that power to electrical energy we can reduce imports of oil and gas and reduce carbon emissions into the atmosphere.

Converting that wave power into electrical energy bring two problems. The first is the technical ability and the technology to convert the potential energy of the waves to electrical energy we can use and the other problem is the cost of achieving this.

There is an enormous quantity of potential energy stored in the waves but where does it come from? Waves are the result of friction from the action of wind passing over the surface of the sea. As the wind blows across the surface it transfers a little of it's energy into movement of the water and over a period of time this energy builds and becomes more concentrated.

The waves begin travelling in the direction of the wind and the energy contained can travel hundreds or even thousands of miles until that energy is released when the wave hits the shore.Waves concentrate the winds energy to such an extent that while solar energy might amount to 100 watts per square metre wave energy is typically around 1000 watts per square metre offering great potential for electrical energy generation if we can find the right way to capture that energy.

The availability of power in waves can be estimated on the basis of wave height and distance between the waves which would allow operators of wave energy generation fields to plan what power they will have available in a day or two by knowing what waves are heading their way.

Scientists have been looking at ways of capturing the energy contained within the waves for decades and there have been many small scale experimental test systems but only now are we starting to see commercial developments in this area.

Any device able to convert wave energy into electricity needs to be very robust to survive the constant wear and tear of the sea and survive the occasional violent storms that are sure to occur now and again. Robustness adds to the cost of such systems and cost is perhaps the biggest obstacle in the way of generating electricity from wave power.

The basic principle of almost all wave energy conversion systems is of a float bobbing up and down on the waves and that motion being converted by various means into electrical energy.

We can put a float on the surface of the sea but  all it will do is bob up and down with the waves. What we need to do is convert that up down motion into energy and one way of doing this is by have a long flexible jointed float where the flexing motion as each section is moved by the waves can be converted into electrical energy.

The sea snake concept is made up of a series of cylindrical floats joined by hinged connections with the motion being converted into usable energy by hydraulic pumps. The snake is tethered and connected to a cable on the sea floor which leads back to the land based shore station where the energy is supplied to the grid.

After many years of development the idea is now being used in commercial installations and if these prove commercially successful we can expect them to appear all over the world.

Another form of wave energy extraction device is a vertical float system which uses the vertical motion of the waves to raise and lower a float which is connected to an energy conversion system which produces electricity.

These types of system can be on the surface or they could be mounted on the seabed with a float rising up to the surface.