Pelagian were contracted to provide detailed route engineering and cable burial risk assessment advice for the Gwynt Y Mor offshore wind farm project. This involved working with both the developer and cable installation companies to provide expert analysis of the seabed hazards for cable routes and wind turbine generator (WTG) foundations.
Project work included the collation of 10 years of geophysical survey data into a unified geospatial dataset, which was used to inform the export and array cable route planning and also construction phase works.
Pelagian’s knowledge of the project and expertise in handling this geospatial data greatly assisted in the planning of WTG construction and cable lay operations, while forming the basis for the developer’s own geographical information database and marine management systems.
Pelagian was contracted to provide expert cable route engineering services for the planned installation of two 5km long power cables between the islands of Java and Bali in Indonesia.
Project work included the geospatial data management of detailed high resolution seabed bathymetry and associated seabed images to determine the location of the existing power cables and plan the routes of the new cables.
The routes proved to be very challenging, with steep rocky slopes reaching depths of 80 metres. The cables were planned to avoid suspensions and sharp rock outcrops so that they could be rock dumped after lay. Pelagian provided an expert analysis of potential cable spans to assist in the cable lay.
Pelagian has been providing cable route engineering support to numerous offshore wind farms in the Irish Sea since 2009, including Walney, Ormonde, West of Duddon Sands and Gwynt Y Mor.
Project work has included the design and layout of export and array cables, landing point optimisation, selection of burial equipment and burial assessment, managing cable crossings over existing seabed infrastructure and geospatial data management.
The seabed in this region provides a number of challenges for cable installation and burial, where mobile sediments, glacial till and boulders are commonplace. The cable route layouts and selection of burial equipment were designed to take into consideration the prevalence of these hard ground conditions and mobile sediments.
In 2014 Pelagian were contracted to research a desk top cable route study for two new domestic fibre-optic cables between Portsmouth on the UK mainland and Ryde on the Isle of Wight.
The Solent was a challenging area for the study. The routes sympathetically considered the important coastal habitats and also numerous marine activities. These included fishing, commercial shipping, recreational boating and yacht races and the planned Portsmouth regional dredging campaign.
The two cable routes were chosen to minimise the impact of both natural and manmade hazards present in the Solent and provide safe and diversified routes between the UK and the Isle of Wight, protecting internet connectivity for the local population.