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.
Collision risk can be defined as the potential for receptors (marine mammals, fish and seabirds) to encounter and collide with the moving parts of MRE devices. At present the greatest concern is associated with collisions between tidal turbines and marine mammals, seabirds, and fish (Sparling et al. 2020). Wave energy devices have fewer submerged moving parts and are generally considered to be more benign with respect to collision risk (Greaves et al. 2016). This Information Note therefore only considers collision risk in relation to marine mammals, seabirds and fish with tidal turbines.