Offshore wind turbines: a driver of renewable energy?

Offshore wind turbines offer considerable potential as a driver of growth in renewable energies and an alternative to land-based wind farms. Specialists forecast that in 2050, they will produce double the energy of nuclear power stations worldwide. This is a strategic issue for France, which needs to catch up in renewable offshore energies and reach its objective of 23% sustainable sources in its energy mix by 2020.

Wind turbines benefit from more frequent, regular and stronger winds at sea than on land. When floating, they have the advantage of overcoming the drawbacks of deep water. The French Environmental and Energy Management Agency (ADEME) has launched a call for expression of interest in this area and allocated two zones for floating wind turbines. One of these is Eolfi’s project off the Breton island of Groix, to which setec is contributing. According to Didier Grosdemange, director of setec in vivo, “Today, only about a dozen floating wind turbines have been installed worldwide. Our skills will eventually be of value abroad.

A number of questions have been raised concerning the potential energy capacity and the limitations in terms of anchorage and usage. The sea is a public domain and as such many stakeholders are involved, particularly given the dynamic nature of the marine industry and the difficulty of limiting a project to a precise area. Finally, the environment is tough, not least in terms of the weather, which requires specific measurement and analysis strategies. The expertise is high level, as demonstrated by the RESIBAD research project, in which setec is a partner. The objective is to develop the relevant expertise and tools to reduce the noise generated underwater during standard operations, marine engineering work, mine clearance, etc. and protect the marine environment. Carried out in cooperation with ENSTA Bretagne engineering school and Altran, this project is already improving our understanding of how bubble plumes can reduce underwater noise, which is one of the key challenges for developing the offshore wind turbine industry. setec is already working on two of the four sites allocated by the French government in 2012: Courcelles-sur-mer with EDF EN, and Saint-Brieuc with Iberdrola. In addition to these different studies, setec is developing its expertise in ecodesign. Didier Grosdemange concludes: “For wind turbines at sea, at ports or on the new Monaco land extension project, for example, we are going to try to add a second ecological benefit, integration with the environment.

The aim is to promote biodiversity by adapting the form of the turbines to create shelters for certain species of fish or rough surfaces that can be colonized by marine life. We are trying to reduce the negative impact of installations and even make a positive impact.”