Biofouling and floating offshore wind turbines

An observation buoy off Groix & Belle-Île

The observation buoy named APPEAL was redeployed on 26 November 2023 off Groix & Belle-Île after extensive maintenance (cleaning, changing the structure and the power supply) and the installation of an innovative experimental device. The aim is to characterise the development of living organisms on submerged infrastructures such as the floating wind turbines that will be deployed in Southern Brittany by 2031.

Extensive research into biocolonisation

This deployment is part of the wider BIODHYL research project, which began in 2023 and aims to define a rigorous protocol for characterising the biocolonisation of floating wind turbine mooring lines and electric cables, using analytical methods to establish the nature of the communities present, their volume and their evolution over time. To do this, sections of synthetic fibre mooring lines and electric cable sheaths are deployed at three depths (-2m, -20m and -40m) and sampled regularly over a two-year period. A full range of measurements is taken to identify the physicochemical parameters influencing biocolonisation (nutrients, oxygen, temperature, chlorophyll, etc.). The structures are also equipped with acceleration sensors and water particle velocity measurements to study fluid-structure dynamics, which is a first.

First stage of a multi-site study

A total of five buoys (3 in the Atlantic and 2 in the Mediterranean) will be equipped and monitored in this way. APPEAL, the first in the series, has already been deployed for 2 years for similar observations as part of previous projects (APPEAL and ABIOP+). It is equipped with an AIS that signals its presence to mariners, and an on-call system has been set up to monitor the buoy’s position by satellite. An acoustic receiver has also been installed. This will be used to detect the passage of tagged fish as part of the FISHOWF research project, which is looking at assessing the effects of offshore wind farms on ichthyofauna using acoustic telemetry.

Photo credit: France Energies Marines