The energy of waves
Waves are formed in the open sea because of wind from the vertical component that transmits energy to the single water particles forced to sink by pressing the lower particles, which in turn are laterally and are obliged to rise. When they tend to push lower down, then they constrain adjacent particles to rise again.
All this involves circular orbits formation.
The height of waves, measured by wave meter, doesn’t normally exceed the 7-8 metres (waves of storm), but they can reach 15-18 metres in exceptional circumstances (like in submarine earthquakes).
Normally in Mediterranean sea they are always less high than in the oceanic ones. The speed goes average at 40 km/h, but it can also arrive at 70 km/h (principally in the affected area) and 500-900 km/h in case of earthquakes.
The sea energy
The sea is a mechanic and thermic source of energy. The use of this source is difficult and at the moment rather expensive.
The waves energy
The energy coming from waves can be optained exploiting the movement of floatings achorated on the abysses with some ropes that are wound on an ax of an alternator, or exploiting the air movement over the waves, but these examples are still experimental results. Another possibility is the use of the energy of the sea tides, with methods similar to the aeolian systems. The main difference is in the stucture of the helix because the water density is higher than the air density and it’s less fast than the air. In the Strait of Messina there’s an experimental system like this.
Tides
The exploitation of tides is another method to produce energy from the sea. The systems to harness this energy are similar to the hydroelectric ones. In facts a dam deteins the water in a basin at the level of the high tide and it lets it out when there’s a low tide; when the level joins the level of the sea, the conduits close and, when the high tide arrives, the conduits are reopened and the water fills up the basin again.
The production of energy
The production of energy from the sea is also possible thanks to the difference of temperature between the seabed and the surface. A thermic engine can exploit the temperature difference to get mechanic energy and, from this, the electric energy. The efficiency of these systems isn’t very elevated, around 5%; however, because the thermic energy accumulated in the ocean is very elevated, it’s possible to get enormous quantities of eletricity. There are similar systems in India and in the Hawaii islands.
