Development of marine renewable energies and the preservation of biodiversity. Renewable energies - Volume 2

Marine energy sources could be rapidly developed in the coming decades, especially if sufficient support is provided by governments and industry for the technologies that are still at the experimental stage. It is essential to identify and assess negative as well as positive effects on the marine environment (both of which must be assessed to determine the net environmental impact of the project, and thus allow the design of possible compensatory measures). This is an essential condition if MRE systems are to be accepted locally. This report by the French Committee of IUCN broadly evaluates the impact of the various existing techniques. The major potential impacts of the development of marine renewable energies on the marine environment that were assessed in this study include: noise, habitat loss or modification, the 'barrier' effect for migration, the risk of collision, disturbances related to electromagnetic fields, and shipping-related hazards for certain species. However, various mitigation measures can be implemented during construction, operation, maintenance, or decommissioning to reduce risks to local biodiversity, such as adapting construction dates, avoiding sensitive sites, or developing a design that takes into account the ecosystem in which the project is located. However, not all technologies have the same impacts. Ongoing research, working models, and development of test sites for techniques with less impact on the environment are all essential. Indeed, the further development of mature technologies such as wind power, which are valuable in terms of economic development, structuring activities, and knowledge of environmental impacts, benefit all types of MRE. However, further research is needed to minimise the impact of these technologies in a climate of continuous improvement (lack of opportunity for hindsight should not be an obstacle, but rather an incentive to share data and experiences). It should be recalled that in this study, only biodiversity has been taken into account: the French Committee of IUCN is well aware of the other issues that legitimately influence political decisions (such as the maturity of the sector, the potential costs of production in the short and long term, social acceptance etc.), and especially the need to promote short-term technical solutions, in order to create and boost the industrial sector at the national level. In view of this first global analysis of the impacts of these sectors on the environment, it would appear that floating wind and offshore wave energy (wave power through coastal development, port dikes and coastal areas have similar impacts to coastal current turbines) are the most appropriate options for a biodiversity-conscious MRE development strategy. It is essential to consider the most productive and least impacting energy systems, while taking account of the development times of each system. As these technologies are not yet at a mature stage of technological development, it would take some years to develop them in French waters. It is also important to be better able to compare MRE systems with existing marine activities and to remember that MREs are in combination with pre-existing disturbances. Depending on the technique used and the species concerned (marine mammals, for example, for whom fishing is the primary source of anthropogenic mortality), fishing, for example, could have potentially greater impacts than MRE. This may also be the case for oil platforms and for some impacts (noise) of maritime transport. It is therefore important to remember that MRE projects do not and will not form the sole source of impacts to marine and coastal environments. It is therefore essential to assess the cumulative impacts of MREs and existing activities at a relevant scale. Strategic environmental analyses conducted on the various French coastlines, as part of the Marine Environment Action Plans, should be used to contain these impacts