Some metals cooled to very low temperatures (typically between -272 and -240°C) acquire the
superconducting state, i.e. the ability to conduct electric current without resistance and, thus, without energy loss. Superconductivity has reached the industrial stage in some sectors for the production of intense magnetic fields such as medical imaging, particle accelerators and tokamaks. The applications of superconductivity to grid cables and current limiters have been the subject of experiments after the discovery in the mid-1980s of “high temperature” superconductivity (-196°C) which allows the use of liquid nitrogen for cryogenic purposes. Superconducting cables carry up to 5 times more energy than standard cables.
Highlights
Superconducting technologies can be used for power lines, current limiters and transformers.
A large number of tests of superconducting power lines have been conducted. Some of them took place many years ago (Long Island 2008: 600 m, 138 kV, 574 MW; Essen 2014: 1000 m, 10 kV, 40 MW), but others are recent (Shingal/Korea 2019: 1000 m, 23 k, 50 MW; Shanghai 2021: 1200 m, 35 kV, 80 MW; Chicago 2021: ~ 100 m, 12 kV, 62 MW) and several are currently under development (Paris/Gare Montparnasse 2025 / 2 links of 60m, 1500V DC, 5 MW; Munich 2025: 150 m/15 km,110 kV AC, 500 MW). We are therefore seeing a renewed interest in this technology. Many experiments with current limiters (10 kV to 138 kV, from a few MVA to a few tens of MVA) have taken place in the USA, Asia (Korea, Japan, China), Germany and the United Kingdom since the 2010s, without leading to a significant deployment of these solutions. Superconducting transformers have also been tested, but it appears that no further work has been done on this solution for about ten years.
These real-world projects provide crucial data on the performance, cost, and operational challenges of superconductor technology, forming the evidence base for any future DSO business case.
Opportunities for DSOs
The opportunities offered by superconductor technologies directly address some of the most pressing strategic challenges facing modern distribution networks.
- High-Capacity Power Transfer in Congested Environments: The primary advantage is the ability to transmit significantly more power through a very small right-of-way. This may allow DSOs to upgrade capacity in dense urban centres while avoiding the extremely high costs, long timescales, and public disruption associated with major civil engineering works for multiple new conventional cable circuits.
- Enabling Renewable Integration and Grid Modernisation: Superconducting Fault Current Limiters (SFCLs) may offer a strategic solution to rising network fault levels, which are a direct consequence of connecting more Distributed Energy Resources (DERs). An SFCL can allow a substation to host more generation without requiring a prohibitively expensive, full-scale replacement of its switchgear and busbars, thereby deferring massive capital expenditure.
- Enhanced Network Resilience and Flexibility: Superconducting cables can be used to create highcapacity interconnections between primary substations. This may strengthen the network topology, provide valuable redundancy, and give operators more flexibility to re-route power during outages or maintenance, improving overall supply security.
Challenges for DSOs
- While promising, the technology presents significant economic, operational, and technical hurdles that must be thoroughly evaluated before any investment.
- Economic Viability and Total Cost of Ownership (TCO): The business case is not yet clear-cut. A DSO must conduct a rigorous TCO analysis comparing a superconducting solution to conventional alternatives. This must include not only the high initial CAPEX (cable, complex cryogenic plant, terminals) but also the continuous OPEX, particularly the significant energy consumption of the cooling systems and the costs of specialist maintenance contracts.
- System Reliability and Maintenance: The reliability of the entire system is paramount. The cryogenic cooling plant represents a critical single point of failure; its failure is equivalent to a cable fault. Furthermore, the time required to repair a fault can be substantially longer than for conventional cables, requiring specialised equipment and skills that are not widely available. To make investment decisions, DSOs need robust data on the Mean Time Between Failures (MTBF) and the Mean Time to Repair (MTTR) of these systems, data that is not really available for these emerging technologies.
- Grid Integration and Protection: Superconducting cables have fundamentally different electrical characteristics (e.g., near-zero impedance) compared to copper or aluminium cables. Integrating them into a hybrid network requires sophisticated engineering studies. Existing grid protection schemes may need to be completely redesigned to ensure that faults can be correctly detected and isolated without causing mis-operation or instability elsewhere in the network.
E.DSO Considerations
A proactive and structured approach is required. DSOs must regularly assess the maturity of superconductive technologies through a strategic roadmap.
- Phase 1 – Monitor & Learn: Actively monitor the operational data, reliability metrics, and real-world costs emerging from key demonstrator projects like Munich’s “SuperLink”. Engage with manufacturers to understand the technology’s development trajectory and supply chain maturity.
- Phase 2 – Identify & Model: Proactively identify specific, high-value “problem locations” within the DSO’s own network where conventional reinforcement is exceptionally difficult or expensive. Conduct detailed desktop studies and business case modelling for these specific scenarios to understand the potential TCO benefits of a superconducting alternative.
- Phase 3 – Pilot & Develop: For DSOs facing imminent and severe grid constraints, collaborating on a smaller-scale pilot project could be a strategic step. This would build invaluable in-house expertise on the practical engineering, installation, and operational realities of the technology before committing to a major, business-critical deployment.
Potential use cases for DSOs
- Urban Centre Infeed: Replacing ageing, capacity-limited fluid-filled cables in dense city centres to meet very high future load growth from electrification of heat and transport.
- Substation Deferral or Avoidance: Using a single superconducting link to provide a massive capacity upgrade to an existing primary substation, thereby deferring or completely avoiding the multi-millioneuro cost of acquiring land for and building a new substation.
- Connecting Power-Intensive Loads: Providing high-capacity, low-footprint grid connections for new large loads such as data centres, gigafactories, or major electric vehicle fleet charging hubs.
- Grid Reinforcement for Renewables: Deploying SFCLs at substations with high penetrations of DERs to manage fault levels and unlock additional capacity for renewable connections.
Ongoing projects
The following projects are key sources of the data needed for the ‘Monitor & Learn’ phase of the DSO strategic roadmap.
- Test operation of an innovative high-temperature superconductor cable has begun in Munich (150 m/15 km, 110 kV AC, 500 MW). A 15-kilometer-long superconducting cable is the subject of ongoing design and testing as part of the “SuperLink” research project. The first 150 meters of the project have been put into operation in 2025 under real conditions to test the functionality and suitability of this technology for everyday use. The cable is being supplied by NKT. The line owner is Stadtwerke München Infrastruktur, a subsidiary of the utility Stadtwerke München.
- A new connection (2 links of 60m, 1500V DC, 5MW) has been installed and is expected to be commissioned in 2025 in Paris, at Montparnasse railway station. The cable is being supplied by Nexans. The line will not be operated by a DSO, but by SNCF-Reseau, the French rail network operator. Superconducting technology was chosen because the space available for the connection was very small.
Last update: 30 September 2025