In a climate dictating an increasing need to route submarine cables through the nearshore environment either to bring marine-derived renewables ashore or to increase network resistance and resilience EirGrid Plc., the Transmission System Operator (TSO) for the Republic of Ireland, commissioned Mott MacDonald Pettit Ltd. to carry out a feasibility study into installing several nearshore cable crossings in Ireland. Investigations were undertaken in order to consider the feasibility of installing proposed submarine high voltage power cables in the nearshore environment. The proposed crossing of the Shannon Estuary as part of a wider project to improve the capacity of the transmission network of the Republic of Ireland is used as an example throughout this paper. Information regarding the geological ground model, meteo-oceanographic and archaeological conditions of the proposed site was limited, necessitating a clear investigation strategy. The investigation included gathering site information on tidal currents, bathymetry and geology through desk studies, hydrographic and geophysical surveys and an intrusive ground investigation. The increasing frequency, need and importance of investigation and planning for submarine cable routes is discussed alongside potential methods for installation in the aggressive nearshore environment.
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