Selecting the cable route
In addition to considering the land options available for the location of the converter station, factors affecting the routeing of the subsea cables have also been considered, including
Physical environment: Where possible, areas of rock, boulder clay and sand waves will be avoided as these can create difficulties in burying the cable.
Biological environment: The shortest cable route across designated conservation areas will be taken to minimise disturbance to the marine biological environment.
Human environment: Careful consideration of the route has been given to avoid all anchorage areas, dredging areas, existing marine disposal areas, wrecks, oil and gas infrastructure and offshore wind farms.
As part of the site selection process, options were identified for the landfall of the subsea cables and the route of the onshore underground cables considering:
- Subsea cables landing technique
- Coastal geology
- Coastal processes
- Beach gradient
- Environmental sensitivity (such as nature conservation)
- Rivers and watercourses
- Existing infrastructure
Land in the vicinity of the service station at Pegwell Bay, close to where the Thanet Offshore Wind Farm cables come ashore, was identified as the preferred option for the landfall. Once onshore, the underground cables will be routed through the Pegwell Bay Country Park and beneath the road from BayPoint Sports Complex (former Pfizer sports ground) to the Richborough site.
In Belgium, the preferred landfall was identified to be west of the existing landfalls of the Belwind and Northwind wind farms and the UK-Belgium Gas Interconnector. The landfalls of the future wind farms have also been taken into account.
A desk-top cable routing study and detailed offshore survey was undertaken to determine an optimum route through English, French and Belgium waters. The environmental impacts of this route have been assessed and an Environmental Report has been prepared.
A seabed survey was carried out using non-intrusive methods (geophysical) and intrusive methods (geotechnical) to provide information on the seabed type, for both engineering and environmental purposes.
The cables will be buried into the seabed either by a plough or trenching machine deployed by the main laying vessel directly or by a support vessel following behind.