The turbine that captures energy from the sea

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The movement of the tides is a tremendous reservoir of power that can be converted into electricity. Off the coast of Scotland, O2, the strongest tidal turbine in the world, is proof of this.

It floats near the coast of Orkney, in the northeast of Scotland, where it must remain for fifteen years in order to supply electricity to 2,000 homes. Its floating base is anchored to the seabed, due to the turbulent nature of the sea there: the powerful currents can reach almost 8 knots during high tides. And this is precisely the interest of the location. Kinetic energy, clean and free, is thus transformed into electricity.


The principle of tidal turbines is not new, nor is it the prerogative of the Scottish company Orbital Marine Power, designer of O2. But usually these are placed directly on the bottom of the ocean. In this case, two nacelles, equipped with blades, are connected to a turbine, on the main structure, by two arms. A hydraulic system lowers or raises them according to need, thus offering the possibility of finding, as close as possible, the ideal current of the tides according to the meteorological hazards. The electricity generated is then routed from the turbine to a dynamic cable, which is itself connected to the terrestrial network.

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The main advantage of this “small” structure is obviously its installation and maintenance cost, which is much lower than that of hydroelectric dams. In addition, O2 is more agile than the heavy turbines permanently placed under the sea. This mini tidal power plant, even fixed on the sea floor by chains, is more easily transportable and adapts to different current conditions, even weak ones. As proof, the company’s river power plant project. Today, the production of hydroelectric energy in the world is still derisory: 0.75% of the needs of the planet. An anomaly, considering that the Earth is 71% covered in water, whose turbulence is just waiting to be exploited.

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