Offshore Elements of AQUIND Interconnector
The offshore element of AQUIND Interconnector will comprise four high-voltage subsea cables spanning the English Channel between Portsmouth in the UK and Normandie in France.
The Subsea Cable Route
The offshore element of AQUIND Interconnector comprises four high-voltage DC subsea cables
that will cover the distance of approximately 190km between Eastney, near Portsmouth, and the Normandie coast near Dieppe in France. The cables, each at approximately 115-150mm in diameter, will be laid in pairs, or individually, together with fibreoptic data transmission cables of a much smaller diameter.
Where seabed conditions allow, the offshore subsea cables will be buried in trenches under the sea
floor such that sufficient protection is provided against ships’ anchors, fishing and natural hazards. Where trenches cannot be excavated, and at crossings of other cables, the subsea cables will be protected using alternative protection systems.
The subsea cable survey corridor has been selected and optimised based on best-practice guidelines through a review of potential landfall sites and a desk top study of seabed geology and existing constraints.
These have included fishing and shipping activity, other subsea cables, environmentally sensitive areas, aggregate extraction areas, offshore windfarms, known wrecks and the like. The marine survey has the been used to refine the preferred cable route within the survey corridor.
The Landing Point
The landing point is the location at which the subsea cables reach land, with subsequent connection to the respective converter stations being made via terrestrial underground cables.
In the UK, the proposed landing site is at Eastney, near Portsmouth. On the French side, the Interconnector’s landing point will be on the Normandie coast near Dieppe. The chosen landfall locations on both sides of the Channel have been shortlisted though an extensive optioneering process. This included detailed consideration of engineering and environmental issues, with particular consideration being given to environmental characteristics of the area including Special Protection Areas and Special Areas of Conservation.
Eastney was chosen as the preferred option, partly due to its relative proximity to the existing substation at Lovedean. Minimising the length of the underground cable route will significantly reduce the environmental impact and the disruption associated with its installation.