French companies unite on superconducting cable project for distant offshore wind farms

November 7, 2025, by Adnan Memija

Air Liquide, CentraleSupélec, ITP Interpipe, Nexans, and RTE have joined forces to develop a project that connects distant offshore wind farms to shore via a High Voltage Alternating Current (HVAC) superconducting transmission system.

The SupraMarine demonstrator project will study the electrical connection between offshore wind farms and the coastline using High-Temperature Superconducting (HTS) cables. Cooled by liquid nitrogen, the cables are said to transport electricity with near-zero energy loss.

The demonstrator would represent a breakthrough in energy transmission from offshore wind farms by adapting and simplifying part of the electrical grid connection, said Nexans. The SupraMarine project would offer an alternative solution to the growing offshore wind energy supply chain challenges while sourcing most of its materials from Europe.

Air Liquide will supply the cryogenic plants featuring its Turbo-Brayton technology, used for maintaining the superconducting state of the cables. The company will also conduct studies on the system’s thermal performance and oversee its cryogenic operations.

CentraleSupélec, through the GeePs laboratory at Université Paris-Saclay, Sorbonne Université, will provide knowledge ranging from experimental platforms to doctoral research student training to overcome key scientific barriers.

ITP Interpipe will design a highly insulated rigid pipe-in-pipe cryostat envelope, while Nexans will be responsible for the development of the HVAC superconducting cables, junctions, and terminations.

RTE will provide insights as a grid operator, ensuring the research aligns with real-world grid integration requirements.

The testing of the project, which was awarded a grant of €7.3 million from the French State by ADEME, is planned to commence in 2028.

In terms of other news coming from Nexans, the company recently completed the final export cable campaign at the 496 MW Dieppe Le Tréport offshore wind farm in France.