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Emmanuel Rollin, director of Ailes Marines: “The drilling campaign is more complicated than expected” – Wind farm in the bay of Saint-Brieuc: years of tension


Where are you with the site and, in particular, with the drilling?

The work is not just about drilling, indeed. In particular, we carried out the pre-slicing for the burial of the cables and moved the boulders. This, five weeks in advance.

As far as drilling is concerned, it is the most complicated operation, due to the heterogeneity of the rock. We have rocks that are 20 times harder than the concrete under the Eiffel Tower. We do indeed encounter layers of dolerite. In the end, we drilled seven holes at the desired depth, where it was the hardest, between 26 and 28 meters. Five more were drilled to 70% of the desired depth. For these, we will have to come back to it. The good news is that we were able to drill, but we are very far from the expected cruising speed, all because of damage.

Before drilling, you had carried out surveys. However, you seem to discover that these sea beds are extremely hard?

From the summer of 2012, we carried out geophysical and geotechnical campaigns which gave us a first level of information. Then, in 2017 and 2018, we started over again. Then came the test campaign, initially scheduled from July to September 2020. Except that the discussions dragged on and, in September 2020, the weather was deplorable. We were therefore not able to carry out all the tests that we wanted. When we came back, in May 2021, we took them back and today we are still in the testing phase. But we encounter such heterogeneity of the soil. The three piles per wind turbine are spaced 25 meters apart. From one point to another, we do not have the same soil. The equipment is pushed to its limits and we must adapt it according to the problems encountered.

“We have rocks that are 20 times harder than the concrete there is under the Eiffel Tower”.

You say you are very far from your cruising speed. Is this likely to call into question the calendar, especially as the shellfish fishing will resume and the weather will be less favorable?

The 2021 campaign is more complicated than expected, but our horizon remains at the end of 2023. We will be able to catch up. Our goal is still the same.

As for the upcoming schedule, a meeting with the prefecture and the Côtes-d’Armor departmental fisheries committee is scheduled to discuss it.

These steps surprise us. All the decisions were judged, including by the Council of State. Finally, all appeals are purged.

“I don’t see why this project should be called into question. “

Are you not afraid of becoming the new Notre-Dame-des-Landes?

The current buzz around the issue does not detract from the relevance of the project. There is an energy problem in Brittany and the project is part of the Breton electricity pact. It will help supply 835,000 inhabitants and fight against global warming. Not to mention the industrial sector that is being set up. As for the threat to biodiversity, the best scientists have looked into the matter. 40 environmental measurements were taken and the conclusions are reassuring. Biodiversity is taken into account. I do not see why this project should be called into question.

Are you not considering an exit and therefore withdrawing from the project?

Such a hypothesis is absolutely irrelevant. It is normal to have a development phase with this technology.