Route selection is extremely complex and usually the most time-consuming process during a subsea interconnector project.
Many factors must be considered before selecting a subsea route, including:
Where possible, areas of rock, boulder clay and sand waves will be avoided as these can create difficulties in burying the cable.
The shortest cable route across designated conservation areas will be taken to minimise disturbance to the marine biological environment.
Careful consideration will be given to avoid all heavily fished areas, anchorage areas, dredging areas, existing marine disposal areas, wrecks, oil and gas infrastructure, and offshore wind farms.
A desk-top cable routing study and detailed offshore survey will be undertaken to determine an optimum route through UK and French waters. The environmental impacts of this route will be assessed, and an environmental report will be issued and publicly available.
A seabed survey will be carried out using non-intrusive methods (geophysical) and intrusive methods (geotechnical) to provide information on the seabed type, for both engineering and environmental purposes.
Wherever possible, to minimize the impact to sea users and to marine life, the cable will be buried into the seabed.
As part of the site selection process, all options will be identified, and the route of the onshore underground cables will consider the following:
The potential marine routes and landings in Guernsey and France have been the subject of a detailed marine route selection assessment. The findings are now being analysed to characterise the seabed sediments and benthic habitats within the preferred study area in French waters.
This data is key to enable the GEM Technical Team to progress the route selection assessment for the Project. As part of this process, all potential environmental and social sensitivities will be taken into consideration.