Everything you need to know about tidal power

🤔 The fact:France has one of the largest marine renewable energy potentials in Europe, thanks to the extent of its maritime space.

📊 The analysis: Tidal energy is part of the renewable energy category (RE), because it is seen as inexhaustible on a human scale and generates little waste or polluting emissions.

🎯 The objective:Diversifying the French energy mix strengthens France's energy sovereignty while encouraging the energy transition.

It is with this in mind that Enerfip invites you to learn more about this renewable energy. Created against all odds, here is our guide to tidal energy!

What is a tidal turbine?

Before we go any further, let us define what a tidal turbine is. While for some this concept is perfectly clear, for others it may be more vague. So, let us remind you that it is a structure that uses the kinetic energy of tides and ocean currents to create mechanical energy. Subsequently, it is transformed into electricity.

💡 Good to know
According to estimates from the Electricity Transmission Network (RTE), France ranks 2nd in terms of tidal resources in Europe.

The different types of tidal turbines

Often related to an underwater wind turbine, a tidal turbine consists of a wheel (the rotating part), a propeller (the motor) and a shaft (the fixed part). However, models vary depending on the technology used.

• Horizontal axis tidal turbine:It is fixed by a base to the seabed with a non-immersive part or mounted on a barge in order to transport it on the water, and then submerge it.
• Vertical axis tidal turbine: Since its propeller is fixed to the mast, it has a lower energy production capacity than the horizontal axis turbine.
• Free turbine tidal turbine: The blades of the tidal turbine are fixed on a circular axis with a central hole, which allows marine fauna not to be impacted by this device.
• Oscillating wing tidal turbine:This technology can only be used in rivers, with a flow of water greater than or equal to 1 m/s.
• Chain-type hydro turbines: a series of hydro turbines are placed next to each other on the seabed or at river mouths.
• Archimedes screw hydro turbine: here, the Archimedes screw mechanism is adapted to generate electricity. How? The potential energy of the water flowing through the installation is transformed into mechanical energy thanks to the rotation of the screw. Subsequently, it is transformed into electricity using a generator.
• Self-supporting tidal turbine: Installed at the end of a cable, the tidal turbine operates according to the movements of the ocean current.

What are the advantages?

💡 Good to know
According to the historic electricity supplier, EDF, France could exploit 2.5 GW (gigawatts) of tidal energy.

Among renewable energy sources, tidal turbines have undeniable advantages.

• It is a green and renewable energy. Non-polluting, free, continuous, inexhaustible, and non-emitting greenhouse gases, tidal energy has it all!
• It is a reliable, 100% predictable energy source, because the tidal cycle is intrinsically linked to the Moon's gravitational forces (specifically for tidal turbines that depend on the tides).
• To produce the same electrical power as a wind turbine, tidal turbines require a smaller installation. Moreover, since the turbines are submerged, the impact on the landscape is limited.
• The cost of tidal energy is competitive. You're wondering how much, aren't you? It's comparable to that of floating wind power, namely less than €80/MWh from 1 GW in operation*.
• Tidal energy has few conflicts with fishing and maritime transport.
• Marine tidal power promotes job creation in France. These cover both the creation and installation of turbines and the maintenance of the farms.

What are the disadvantages?

Even though we would have liked tidal turbines to be flawless, they do have some disadvantages.

• Maintaining tidal turbines is cumbersome. What does that mean? You have to take the structure out of the water, dismantle the propeller, check the blades for erosion... We'll let you take the measure of maintaining a tidal turbine.
• Rust and corrosion due to the salinity of seawater unfortunately prevent the recovery of the various components of a tidal turbine.
• The construction and installation of a tidal turbine leads to possible noise pollution.

How are tidal turbine projects developing in France?

💡 Good to know
The English Channel and the Atlantic coasts have 3 sites with very interesting potential: the Alderney Race and the Barfleur Race, in the Cotentin, as well as the Fromveur Passage, in Brittany.

With its 11 million km² of maritime domain, France is the second country in Europe, after the United Kingdom, to have the most suitable areas for the development of tidal energy projects. So, what are the conditions required for the installation of a tidal turbine? To install the various equipment dedicated to the production of tidal energy, the area must have a strong tidal current, a depth of 30 to 40 meters and, of course, be located close to the coast.

For the moment, only sites located in the north of France have the energy potential necessary for the installation of a tidal energy project. In the Mediterranean, with the exception of the Strait of Messina, the tides are not powerful enough.

Do you also want to contribute to the development of renewable energy projects and participate in the transition to cleaner energy? Make an appointment with the Investor Relations department without further delay!