Marine energies: with winds and tides!

As major territories in the energy transition, the coasts are one of France's assets in the production of renewable marine energy. Offshore wind turbines, tidal turbines... while waiting for the first projects to be completed, the sectors are emerging and taking shape. But obstacles still hamper their development. Against the current, France must now increase its installed capacity tenfold by 2023.

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Certainly, the will exists. Public authorities have demonstrated this in recent years. Efforts have been made to support the development of marine energy. The implementation of purchase tariffs, the structuring of calls for tenders, assistance from ADEME[1], and regional support for businesses have enabled the sector and its various stakeholders to gain in importance. But with more than 4,500 km of coastline, France doesn't have a single offshore wind turbine. Not yet.

Wind in the Blades

By constantly sounding the alarm about the future of offshore wind power, local elected officials and industry leaders have finally been heard. The six projects already awarded under the previous term were recently confirmed by Emmanuel Macron. In the meantime, the state has renegotiated subsidies and electricity buyback prices downwards. At €150 per MWh, offshore wind turbines are not yet competitive with onshore renewable energy[1], but they are approaching the price of EPR reactors[2] under construction in the United Kingdom (€105). Located on the Channel and Atlantic coasts, the six projects represent 3,000 MW of installed capacity, just enough to meet the targets set for renewable energy by 2023. Will they be in service by that date? Nothing is less certain.

Social acceptability

In both the Channel and the Atlantic coast, numerous administrative appeals have been filed. Concerned about their horizons and the impact on the fishing sector, opponents are significantly slowing the progress of projects. In the Mediterranean, the situation is quite different. Three floating wind farms are planned. But these are floating wind turbines, an emerging technology that can limit the visual and environmental impact. To date, the acceptability of floating wind projects is well on its way. Thus, on the Eolmed project, the consultation work associated with crowdfunding for the wind resource study brought together the populations and maritime professionals of Gruissan and Port-la-nouvelle.

Be informed

While the wind remains more favorable offshore than on land, tidal power also benefits from the energy provided by marine and river currents. A booming technology, its development is generating a lot of interest. But like any emerging sector, it has seen many twists and turns. The latest: the withdrawal of Naval Energie[3]. Following in the footsteps of Siemens and Total, the group is leaving the ship a month after the inauguration of its manufacturing plant in Cherbourg. The successive abandonment of projects off the Cotentin coast, combined with the decision by Nicolas Hulot's ministry to launch a new study on the potential of tidal power, finally convinced Naval Group to throw in the towel. Nevertheless, the sector remains active. The Sabella turbines are being tested in Fromveur-Ouessan, and those of Hydroquest will be tested in early 2019 in Paimpol-Bréhat.

Up and down

The turbines are also at the heart of a technology that has already proven itself: tidal energy. The Rance dam has been demonstrating this since 1966. Its 240 MW capacity covers the needs of 225,000 inhabitants. While there are few of these in the world, many projects are under consideration. Among them is the Tidal Lagoon Power tidal power plant. This involves building an artificial lagoon in Swansea Bay, 60 km from Cardiff. Using the ebb and flow of the daily tides, a system of locks powers turbines for 14 hours a day. Only the project's cost, £1.3 billion, is a handicap. While the British government has withdrawn its financial support, a recent study commissioned by Swansea University reaffirms the project's viability. The Welsh government could allow it to emerge from the water.

Waves, heat, and salt

Other technologies are at less advanced, or even exploratory, stages. This is the case with osmotic energy. The principle is to use the difference in salinity between freshwater and seawater. This mixing, occurring every day in estuaries, releases energy. Recovering it is what French researchers and industrialists are working on, because its potential is enormous. Another avenue being studied is thermal energy. This time, the aim is to exploit the temperature difference between deep water at 5°C and warm surface water at 25°C. Adapted to tropical areas, this technology is being tested with a prototype installed in Réunion. Finally, wave and swell energy is more advanced. While the sector is at a standstill in France, Australia is a pioneer. The first wave power plant feeding a network has been in operation since 2015. 47 of you responded to this question. The energetic attraction of the August sea has had its effect. Even so, the wind wins! Half of the voters are in favor of wind turbines (fixed or floating). Logically, this is the most advanced sector and the one with the lowest costs to date. Hydrokinetic technologies, including tidal power, follow. A quarter of those who responded advocate for them. Recently under the media spotlight, interest in these solutions is confirmed. More surprising is the number of votes in favor of wave energy: 17%. Proof that a French sector would make sense for some of our readers. Finally, ocean thermal energy and osmotic energy together garnered 8% of the votes. The confidentiality and experimental nature of their development undoubtedly explain this result.

Untapped deposits

With the second largest ocean area in the world, France is not living up to the potential offered by marine energy. The political ambitions expressed in recent years are currently buried beneath the sand. To date, with the exception of the Rance dam (desired by General de Gaulle), not a single kilowatt-hour has been produced by marine resources. Certainly, recent decisions on offshore wind power will help to catch up somewhat on short-term objectives. But beyond that? It will undoubtedly be necessary to continue along the path of political voluntarism. Let's bet that the first version of the Multiannual Energy Programming (PPE), expected by September, will appear as the beacon for marine energies.

Cyrille Arnoux, web editorial manager

[1] French Environment and Energy Management Agency

[2] Renewable energies

[3] Nuclear reactor project third generation

[4] Formerly DCNS (a company more than 62% owned by the French state)