Today, many countries have become aware of the need to integrate ‘renewable energy’ into their energy policies to compensate for their limited resources of combustible fossil fuels, achieve energy security for the future and reduce the effects of climate change that result from human activities (MacKay, 2009).
There are numerous possibilities for using the sea to producing energy. Notably the energy of waves (houlomotrice), the energy of currents (hydrolienne), the energy of tides (maremotrice), the energy of the wind (eolienne), the thermal energy (ETM), energy related to gradients of salt content (salinity), etc.
Suitable sites are selected by the promoters based on technical criteria: depth, reasonable distance from the coast, near a landfall point, nature of the seabed, etc. These sites could correspond with areas important for the good functioning of ecosystems (such as spawning and nursery) or pathways of migratory species. Generally, the coastal zone is a key area for the whole of the food chain (plankton, fish and invertebrates, marine mammals, birds). Marine energy has an impact on all compartments of the marine environment and land in relation with these: the water column, the seabed, the airspace etc.
To avoid impacting these important ecological and trophic areas, it is necessary to know the levels of conservation, sensitivity and resilience of species and habitats when planning this type of project. These assessments are used to define sites with the least environmental constraints. Subsequently, integrated environmental impact assessments, both positive and negative, will identify some of the environmental benefits and damage that will occur during implantation and implementation of MRE, and thus provide plans for evasive action, repair and restoration to compensate for these damages.
The scientific literature points out that the potential impacts of this type of activity will be different depending on the various phases of construction, operation and dismantling. These effects are of concern as they will have an impact on habitats and species displacement, changes in turbidity of the water, effects on species associated with vibrations and noise, the magnetic fields of cable networks, the effects of collisions with birds (Annex 1).