Uncertainties and environmental impact dependencies on array changes



This report presents the uncertainties and environmental impact dependencies on array changes. It includes content about wave and tidal uncertainties as well as environmental issues related to array design.

For wave uncertainties, this document describes the main theoretical limitations with particular regards to the inviscid and irrotational flow, water depth, linearized wave-structure interaction problem and wave field representation. The error analysis section deals with the influence of bathymetry in the wave resource as well as the influence of wave directional spreading in hydrodynamic interaction. Statistical and deterministic approaches are also described in order to address the environmental input uncertainties and how these uncertainties are reflected in the wave sub module output.

Theoretical limitations for tidal technology uncertainties are discussed considering flow field modelling, wake interactions, horizontal-boundary assumptions, vertical-dimension assumptions and device yawing. The error analysis is mainly based on the PerAWaT flume experiments.

Environmental issues are firstly discussed through a synoptic review of energy extraction, collision risks, turbidity, underwater noise, chemical pollution as well as potential beneficial effects such as reef effect, reserve effect and resting place. General and specific (based on a scenario) recommendations are then given in order to minimize environmental impacts. Finally, the Environmental Impact Assessment Module (EIAM) is also described with its main functions related to environmental impact dependencies on array changes.