Superconductivity: transforming future rail transport

Superconductivity was in the spotlight during the UIC conference held in Paris on December 2024 to which Nexans took part in partnership with SNCF Réseau. Superconducting technology was indeed showcased as revolutionary for the rail industry, positioning it as a game-changer in the future of rail transport.

Superconductivity is increasingly being utilized in industrial applications with notable potential to reshape and revolutionize power transmission including rail networks. Through the adoption of superconducting cables and fault current limiters, the rail industry stands to enhance efficiency, increase capacity, and promote sustainability. These advancements align with global decarbonisation objectives and facilitate the transition towards more efficient energy systems.

Superconductivity to help overcome rail industry challenges

The rail industry faces great challenges that could be overcome by extending the use of groundbreaking technologies like superconductivity, which is besides part of the IGTs (Innovative Grid Technologies – supported by CurrENT, a key industry association representing innovative grid technology companies operating in Europe)..

#1. Modernization of railway infrastructure involves refurbishing the infrastructure and enhancing network reliability, which are key challenges for network operators

Strengthening lines, increasing speeds, accommodating more trains, and thereby improving capacity and mitigating carbon footprint, require infrastructure improvements, particularly in densely populated areas. This includes track regeneration and geometry adjustments, upgrading the overhead contact system, constructing passing loops, replacing level crossings and pinch points, and alleviating congestion at junctions. 

Superconducting DC cables and superconducting fault current limiters (SFCL) are currently contributing to the modernization of railway systems and subsequent to Net-Zero programs. The French National Railway Company (SNCF Réseau) announced several projects where superconductivity will play a critical role, including efforts to regenerate traction power, increase the power availability on their rail network and expand the deployment of SFCLs to enhance networks’ reliability.
 

Some recent examples on how superconducting systems can contribute to rail efficiency:

• The superconducting MagLev and the Chuo Shinkansen, which connect Tokyo and Osaka at a speed of 505 km/h in just 67 minutes (438 km), have now become a reality.
• Gare de Montparnasse SuperRail project in Paris will ensure 16 trains can be operated at the same time thanks to the superconducting cable systems powering up the current network.
• In Bussurel city, the railway network will achieve unprecedented continuous operational performances thus ensuring a better control of network stability and further contributing to an increased train punctuality  All these benefits were made possible thanks to SFCL (Superconducting Faut Current Limiter).

#2. Sustainability and performance : combining efficiency with environmental responsibility whilst ensuring economic sustainability and performance

Rail fosters green mobility with its environmental benefits, addressing sustainability, mass transit and freight challenges. As a greener alternative, the rail freight industry can replace over 100 trucks with one freight train, significantly reducing carbon emissions and contributing to tackling climate change. Building a sustainable rail industry requires considering environmental, social and economic factors.

Superconductivity is currently advancing industrial applications, offering significant potential to transform rail networks. By incorporating superconducting cables and fault current limiters, the rail industry can attain exceptional levels of efficiency, capacity and sustainability. This progress aligns with global objectives for decarbonisation and fosters an energy transition.

Furthermore, high-temperature superconductivity offers significant cost reductions. Numerous projects have demonstrated millions of euros in savings by decreasing capital expenditures compared to conventional copper or aluminium cables. Although the savings are contingent upon project location and complexity, HTS technology helps overcome permitting right-of-way challenges, enabling efficient high-voltage transmission at medium voltage levels. As copper and aluminium become increasingly scarce and expensive, the return on investment for HTS technology will improve.

The Superconducting value chain, including Advanced Conductors such as HTS Wires, is investing millions every year not only to increase industrial capacities but also to reduce the cost of components.

#3. Industrial partnership to foster innovation and provide more advanced technologies

The conference highlighted the significance of international collaborations in accelerating innovation within the rail sector and beyond. Many projects and initiatives aim at further developing superconducting technologies. These projects go far beyond the pure railway industry and would benefit other sectors – among which:

• Offshore wind: HTS technology is transforming offshore wind energy. The SupraMarine consortium (RTE, ITP, Nexans and a world leader in the Cryogencics cooling systems) is developing a 100km HVAC superconducting export cable that aims at reducing costs by approximately 1 billion euros for a 2 GW offshore wind project.

• Supernode ltd in Ireland is developing a superconducting HVDC solution which will also support the industry in becoming more efficient and transmitting electrical power that conventional cables cannot achieve. 

• Aerospace: Airbus shared their roadmap towards zero emission flight with superconducting cables playing a critical role. Building on the ASCEND project, the CRYOPROP initiative aims to further develop superconducting technologies to support cleaner aviation.

• Industry : leading academics highlighted their research in advancing superconductivity in industry and confirming the huge potential benefits of the technology including Power Transmission and Distribution.

Great opportunities lie ahead with regards potential applications of superconducting technology, the HTS wire industry is heavily investing to meet growing demand for HTS cables. New production capacities aim to reduce wire costs by a factor of four using advanced industrial processes.