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Optimising submarine cable routes from offshore wind farms – site suitability mapping
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Date
2024
Authors
Walsh, Kevin
Journal Title
Journal ISSN
Volume Title
Publisher
University College Cork
Published Version
Abstract
The Irish Government’s Climate Action Plan aims to increase renewable energy generation capacity to 22 GW by 2030, with at least 5 GW of this to be produced by offshore windfarms. The potential to harness and develop this resource is significant; however not all areas offshore are suitable. Moreover, not all routes from windfarms to land are suitable for the submarine cables needed to transfer the energy produced offshore back to the onshore grid.
This project leverages geospatial analysis to identify optimal routes for submarine export cables, enhancing our understanding of marine and coastal geomorphology and the potential hazards associated with these environments. This research is focused on the South and West coasts of Ireland, a region with substantial potential for offshore wind energy development, particularly floating wind turbine platforms.
A comprehensive geospatial repository of publicly available data was compiled, incorporating key features relevant to submarine cable route feasibility. These criteria layers include bathymetric, geological and ecological data, as well as information on human activities in the area, to assess the potential hazards to a submarine cable within a particular region. Criteria weights were calculated for two scenarios using the Analytical Hierarchical Process, based on expert opinion, while a third scenario applied equal weighting to each layer to evaluate the impact of these weights
The resulting maps classify regions off the South and West coasts of Ireland into zones of suitability for submarine export cables. A Least Cost Path Algorithm was then implemented in ArcGIS Pro along these surfaces, which identified the most optimal routes for each scenario. Particular focus was paid to those parts of the study area where there are current plans for offshore wind energy development, as identified during phase I and II of the Irish Governments Offshore Renewable Energy Development Plan.
In a novel application, INFOMAR sub-bottom profile data was analysed within two key regions off the South Coast highlighted from the route selection analysis. This study presents some of the first examples of utilising this openly available dataset for spatial planning of offshore infrastructure. The resulting sediment thickness maps derived from this analysis facilitated routing through areas where seabed sediment depths are adequate for cable burial, thereby minimising the risk of damage from external hazards that could shorten the lifespan of the cable and lead to costly repairs.
The findings detailed within this study provide a useful tool for policy makers and developers in the feasibility stages. In a broader context, given the vast size of Ireland’s offshore territory, these findings can be applied by planners to create objective and standardised cable routes having both immediate economic and environmental benefits. The use of publicly available data herein can reduce the reliance on extensive geophysical surveys, which are not only expensive and time-consuming but also can be environmentally detrimental, particularly due to the impact of anthropogenic sound on marine mammals. By lowering the costs associated with marine surveys and identifying optimal routes that reduce the risk to submarine cables, this approach can encourage international developers to invest in offshore energy in Ireland, ultimately supporting the rapid and widescale rollout of renewable energy needed to meet national targets. The innovative approaches and datasets detailed in this thesis not only advance the precision of submarine cable routing but also establish a replicable framework for offshore wind energy projects, thereby contributing to the efficient and sustainable growth of global renewable energy infrastructure.
Description
Keywords
GIS , Submarine export cables , Offshore wind energy , Multi-criteria decision-making analysis , Site suitability , Route selection , Sub-bottom profile analysis
Citation
Walsh, K. 2024. Optimising submarine cable routes from offshore wind farms – site suitability mapping. MRes Thesis, University College Cork.