Offshore renewable energy recovery systems have specific characteristics that lead to a high sensitivity to biofouling for some components. This represents a challenge for engineers during the design and maintenance phases, but also for certification bodies. As ORE farms are set up in very dynamic and inaccessible environments, the biofouling that forms there is often very little known. However, in order to predict the effects of biofouling, it is essential to know its composition and to better understand its spatial and temporal variability.
Through several R&D projects, France Energies Marines, its members and partners are gradually building up a genuine biofouling observatory on the various French coastlines, close to the areas where future offshore wind farms will be built. On the Atlantic side, two sites have recently been instrumented:
- The buoy launched at the end of April at the site of the future Groix & Belle-Île floating wind farm has two mooring lines, one of which is equipped with frames with collectors that can be oriented in the current, fixed every 10 m to study biocolonisation according to depth. Since 9 July, six plate holders have been added to the star under the buoy, so that PVC holders can be attached,
- On 28 July, a system of plate holders was deployed on the drift of the buoy located on the Basse des Chats, with the assistance of the Phares & Balises.
The two instrumented sites are about 10 km apart, which is the maximum width of a commercial offshore farm. Although the swell and current conditions are similar, the bathymetry and proximity to the coast are significantly different and may clearly influence the biochemical parameters of the two sites and induce different colonisations. It will therefore be interesting to follow the observations that will be made in the coming months.
Photo credit: France Energies Marines