French transmission system operator (TSO) RTE Réseau Transport d’Electricité plans to issue calls for tenders for geophysical, geotechnical and UXO surveys for multiple projects from 2025 to 2026.
RTE, responsible for developing, implementing and operating offshore wind farm connections to the French public power transmission system, issued early information notices about the tenders on 23 July.
In the spring of 2025, the summer of 2025, and in 2026, RTE plans to invite separate tenders for geophysical surveys for offshore substations and subsea cable routes (excluding landfall), UXO surveys for offshore substations and subsea cables, and geotechnical surveys for offshore substations.
The specific call for tenders may include more than one project.
The geophysical survey contractor(s) will be in charge of the full scope covering the subsea cable routes from the nearshore location to the offshore substation location, which is in a water depth of at least 40 metres, and the offshore substation location.
The UXO survey contractor(s) will also be awarded full scope covering the detection and identification of UXO across the subsea cable routes and the location of the substation foundation.
The geotechnical surveys, including a preliminary UXO survey and ALARP UXO certificate, will cover the future location of the offshore substation foundation in deep water.
In December 2023, RTE launched a tender for the delivery of three offshore substations to connect three floating offshore wind farms that will be built off Southern Brittany and in the French Mediterranean to the grid on land.
Earlier this year, the French TSO signed a contract with the Hitachi Energy – Chantiers de l’Atlantique consortium for the construction of the first offshore substations and DC converter stations for two offshore wind farms that will be built off Ile d’Oléron (AO7) and Normandy (AO8).