High-power medium-voltage superconducting cables for Europe's energy transition

Superconducting cables have been proven in multiple tests and utility installations, which highlighted their compact size, low energy losses, and reliability. This can make the technology economically attractive for many applications. A particularly interesting case is the DC high-power transfer at medium voltage (MVDC). The high current capability of the superconductor allows for a reduction in voltage while maintaining or increasing the power transfer level. A main motivation for the development of MVDC superconducting export cables is that costly and complex high-voltage converter stations can be eliminated when going from high- to medium-voltage, allowing for significant overall cost reductions. This is very relevant for offshore applications. The European project SCARLET develops and demonstrates MVDC cables at the gigawatt level, including their protection requirements. Some of the SCARLET highlights are offshore superconducting cables, the combined hydrogen and electricity transmission in the same pipeline, and the demonstration of a 10 kADC fault current limiter module. This paper describes the superconducting MVDC cable concepts and the main challenges needed to develop and type test the cables.