The Biscay Gulf electrical interconnection developer Inelfe has issued a tender call for geophysical and geotechnical survey services to be performed in the Biscay Gulf.
The purposes of the investigations are the determination of the detailed seabed conditions and stratigraphy with detailed characterization of the materials in the surface and sub-surface soil layers in order to inform the installation of submarine cables.
The Biscay Gulf interconnector between Spain and France is a joint project developed by Inelfe on behalf of Réseau Transport d’Electricité (RTE) and Red Eléctica de España (REE).
To remind, initial geological studies of the seabed carried out by RTE and REE revealed ground instability along the edge of the Capbreton Canyon. The two TSOs were therefore forced to abandon this solution and define a new route around the canyon.
The geophysical investigation will include both surface and sub-surface survey. The geotechnical investigation will consist in CPTs, vibro cores, rock cores and similar.
The interconnector consists of the construction of a 2GW link. This link is composed of two circuits rated 1GW each for DC operating voltage of 400 kV, comprised of 4 power cables, 4 converter station terminals located close to 400 kV Cubnezais substation (France) and Gatica substation (Spain).
The length of the route is estimated to be approximately 400 kilometers starting in Spanish Pais Vasco region (near Bilbao) to an ending point in Nouvelle Aquitaine (Gironde department, near Bordeaux).
UXO survey could potentially be required as well.
Deadline for receipt of tenders or requests to participate is set for April 06, 2020.