Longitude supports Saint-Nazaire cable works

In: Windfarms
15/09/2020
Longitude, the engineering and design branch of LOC Group, has completed a range of environmental engineering analyses supporting the planning for upcoming export cable installation operations for the Saint-Nazaire offshore wind farm.

The contract was provided by Prysmian Group and included analysis of vessel grounding and mooring in nearshore locations, landfall cable pull-in analysis, to ensure cable integrity, export cable free lay from the nearshore to the wind farm, survival analysis for vessel operations in bad weather and seabed evaluation to ensure the cable remains stable prior to being buried.

Longitude’s work in metocean engineering provided an understanding of tide, current and waves at the shore approach location, including generating 3D hydrodynamic modelling. This supported Prysmian’s ability to plan operations, given strong and changing tidal currents, due to the location of the project, close to a river estuary.


The wider LOC Renewables team has also contributed at other stages of the
Saint-Nazaire project under other contracts, including a geotechnical analysis of leg penetration and soil stiffness.

Andrew Butler, Managing Director of Longitude, added:“Delivering the scope of work under this agreement demonstrates the breadth of services we can offer across a project’s lifecycle, and the value our multidisciplinary approach adds to clients’ projects. An example of this is the provision of cable stability analysis and work on the landfall cable pull-in. In-depth stability analysis requires consideration of a range of potentially contributing factors. To understand these factors you need a specialised combination of environmental engineering expertise, providing an analysis of the soil properties from a geoscience perspective, and tidal, current and weather conditions for the location from the metocean perspective.”

The 480 MW
Saint-Nazaire offshore wind farm will be located between 12 km and 20 km off the coast of the Guerande peninsula in western France. Water depths at the site range between 12 and 25 metres. The project will feature 80 of  GE's Haliade 150-6MW wind turbines, each with a 6 MW capacity. It is expected to generate enough electricity to supply 20% of the Loire-Atlantique department's power.

For more information on offshore wind farms worldwide, click here. You can view cable routes for interconnectors and wind farms using 4C Offshore's Interactive Map.

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