These Information Notes will support careful consideration of how, for a particular development, potential impacts that are considered low risk could be safely retired from further detailed consideration within Environmental Impact Assessments (EIA), where available evidence supports this approach. Ocean Energy Systems-Environmental (OES-Environmental) has set out a general process for risk retirement1,2 but for developments in Welsh waters, risk retirement should always be discussed between developers and Natural Resources Wales (NRW) at the pre-application stage. In the context of these Information Notes, risk retirement implies that all potential impacts are included for consideration at the project scoping stage, and that following a review of the evidence some impacts may be ‘scoped out’ of any further detailed assessment to focus EIA on key significant impacts3. In all cases, potential impacts should be acknowledged in EIAs, with evidence-based justifications describing why particular impacts could be ‘scoped out’ of further detailed assessment.
MRE devices are designed to remove energy from the marine system in order to generate electricity and it has been suggested that in some configurations this could lead to near field and far field changes in some of the important physical processes in the ocean or along coastlines. These ocean and coastal processes include hydrodynamics, tidal circulation, wave action, sediment transport and temperature and salinity gradients. However, changes to oceanographic systems resulting from large-scale MRE developments need to be viewed within the context of the ocean as a dynamic system. It is important to compare the magnitude of potential changes caused by MRE developments to the natural variation of key parameters in marine systems (Whiting and Chang, 2020).