Superconductivity: Revolutionizing energy networks

Superconductivity was in the spotlight during the CIRED conference held in Geneva on June 2025. A strong focus was set on how to accelerate the energy transition, particularly for this edition where the onus was on the challenges and opportunities in forecasting the amount of grid and transmission lines needed to support the electrification of economy and Renewable Energy Transmission. Superconducting technology was a perfect fit for such a theme, as it represents a game-changer in the future of energy networks thanks to its revolutionary character and the potential it represents to enhance the resilience of energy grids. 

Nexans had been selected to showcase two of its groundbreaking superconducting cable projects. This recognition by CIRED’s Technical Committees, which includes the acceptance of three posters and one oral session, highlights Nexans’ leadership and innovation in High-Temperature Superconducting (HTS) cables — a key enabler for modernizing and decarbonizing the power grid.

Featured Papers:

• Paper #956 – Scarlet project: High-Power Medium-Voltage Superconducting Cables for Europe’s Energy Transition
  Presenter: Arnaud ALLAIS
  Key benefits of MVDC HTS cable technology:
  • Enables voltage reduction while maintaining or increasing power transfer
  • Simplifies system architecture, reducing overall costs
  • Compact design with minimal energy loss and space requirement
  • Actively contributes to international standardization efforts
• Paper #1159 - Superconducting Microgrid: Supporting Synergies between Energy and Data Centres
  Presenter: Paul Bakhos, MBA, PMP Bakhos
  Advantages of superconducting cables for low-voltage applications:
  • Zero resistance and zero energy loss
  • No voltage drop or electromagnetic field (EMF) emissions
  • Simplified and compact system design vs conventional resistive cables
• Paper #967 – SuperRail: A World First in Superconductivity for Railway Electrification
  Presenter: Yann Duclot
  A revolutionary step for the electrification of railway infrastructure at Paris Gare de Montparnasse with SNCF Réseau:
  • Adding 5.3 MW of capacity through two 1500V DC @ 3500A HTS Cables
  • Enabling operation of 16 additional railcars, increasing passenger capacity up to 90 million per year
  • Achieved without modifying the existing infrastructure, using two spare conduits to install the HTS cables

Superconductivity to accelerate the Energy transition & Electrification

Superconductivity is increasingly being utilized across various applications with notable potential to reshape and revolutionize power transmission and distribution networks. Through the adoption of superconducting cables and fault current limiters, the energy sector 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.

La supraconductivité aide à relever les défis de l'industrie ferroviaire

The world is electrifying faster because it's the most viable path to reduce emissions, improve efficiency, increase energy security, and modernize infrastructure driven by economics, innovation, and climate imperatives. The industry is accelerating at an unprecedented pace and scale. The future of our planet relies on the transition to renewable energy sources. It is no longer a question of if, but when this transition will occur. As the security of the electric grid becomes increasingly critical, it is imperative to establish a sustainable power grid.

For over a century, grids have been the backbone of electricity systems distributing electricity to various sectors. With the rise of electric cars and heat pumps, electricity is now replacing fossil fuels in new areas, increasing grid demands. Additionally, the rapid expansion of renewable energy projects necessitates more power lines and efficient grids to ensure reliable power supply.

As the world moves towards an electrified future driven by renewable energy, electric vehicles (EVs), and industrial electrification, energy distribution grids encounter significant challenges. These include grid overloads, delays in connecting distributed energy resources (DERs), frequency instabilities, and inadequate infrastructure upgrades. Addressing these issues offers an opportunity to reconsider and redesign the operation of global grids.

La supraconductivité aide à relever les défis de l'industrie ferroviaire

#1. Modern, smart and expanded grids are essential for successful energy transitions

#2. Electric Grid Security & Infrastructure : Grids risk becoming the weak link of clean energy transitions

#3. Cost and Investment of Renewable Electric Grid Security: Action today can secure grids for the future

#1. Modern, smart and expanded grids are essential for successful energy transitions

Grids, the backbone of modern electricity systems, are becoming crucial as clean energy transitions advance, yet they often get overlooked. For over a century, grids have powered homes, businesses, and industries. Clean energy shifts are transforming our energy systems, increasing electricity's role in economies. Thus, achieving net zero emissions requires larger, stronger, and smarter grids.

Achieving national energy and climate goals requires global electricity use to grow 20% faster in the next decade than the previous one. To reach net zero emissions by 2050, limiting temperature rise to 1.5 °C, electricity demand must increase even more rapidly. Expanded grids are essential for growth as electric vehicles, heating and cooling systems, and hydrogen production scale up using electrolysis.

To meet national goals, over 80 million kilometres of grids need to be added or refurbished by 2040. Grids are crucial for decarbonising electricity and integrating renewables. If countries achieve their energy and climate targets, wind and solar PV will account for over 80% of the global power capacity increase in the next two decades, up from less than 40% previously. In the IEA's Net Zero Emissions by 2050 Scenario, wind and solar make up nearly 90% of the increase. This rapid deployment of renewable energy requires modernising distribution grids and building new transmission corridors to connect remote renewable resources with demand centres.

Modern digital grids are crucial for ensuring electricity security during clean energy transitions. As solar PV and wind power increase, systems must become more flexible to handle output changes. To meet climate goals, system flexibility needs to double by 2030. This requires new grid operations, leveraging distributed resources like rooftop solar, and deploying grid-enhancing technologies while using demand response and energy storage through digitalisation.
 

Some key IGTs (Innovative Grid Technologies) are ready, including Superconductivity.

Superconducting cable systems have a critical role to play in addressing these challenges.

As well as being highly energy efficient and reliable, superconducting systems are less disruptive to install and require much less space than conventional cables and overhead lines. Transmission and distribution system operators can benefit by integrating superconducting cable systems into their networks:

• boost the capacity and resilience of urban grids : distribution system operators need cost-effective and non- disruptive ways to upgrade city power supplies. Superconducting cables are capable of transmitting an enormous amount of electrical energy in a remarkably narrow corridor – typically only one metre wide. This not only minimises costs, but also reduces the disruption typically caused by civil works. Another benefit is that electricity can be transmitted at medium voltage. This makes it possible to deploy “remote substations” in the urban fringe and to avoid high-voltage transformers in the city centre – a substantial saving. Meanwhile, superconducting cables boost resilience by making it possible to provide cost-effective interconnections between substations.

• enable the energy transition: decentralised generation increases the need for high-efficiency transmission: Superconducting cable systems offer high-efficiency bulk power transmission over long distances, with none of the resistive losses encountered in conventional high-voltage lines and cables. High-voltage DC (HVDC) superconducting cable systems are particularly suited to this application. Nexans has qualified a 320 kV DC superconducting cable for currents of up to 10 kA with a 3.2 GW power transmission capability.

#2. Electric Grid Security & Infrastructure : Grids risk becoming the weak link of clean energy transitions

At least 3,000 gigawatts (GW) of renewable power projects are waiting to connect to grids, including 1,500 GW in advanced stages—five times the solar and wind capacity added in 2022. This indicates that grid connection is becoming a bottleneck for achieving net zero emissions. The number of pending projects may be even higher as current data covers only half of global wind and solar PV capacity. 

The grid is expected to significantly expand by 2050 under all net-zero scenarios. Optimising power flows across the system will be important to minimise the need for extensive grid construction, thereby reducing bottlenecks in deploying clean electrification. Transitioning to a flexible power system, where demand can adjust to variable supply sources, will be essential. However, even with advanced optimisation, constructing new grids will still be necessary. Thus, maintaining focus on the challenges of grid construction remains important.

Innovative grid technologies could materially improve the efficiency of power flows on to the system: via existing networks with changes to pylons and wires: this would be, for example, by increasing the capacity for a given line, such as with advanced conductors, superconductors, voltage upgrades (with larger pylons), double circuiting (through adding another set of lines).

The Energy Transition relies on distributed renewable generation, new transportation paradigms, and enhanced energy efficiency. HTS technologies offer solutions to many of these challenges.

Superconducting grids can facilitate the integration of large-scale renewable energy sources, such as offshore wind farms and remote solar power plants, by enabling efficient long-distance transmission of bulk power with minimal losses. This can overcome geographical limitations and unlock the full potential of renewable energy resources.

New generation assets – particularly renewables such as wind and solar – are typically sited in remote locations, which means that extensive deployments of new grid infrastructure are required in previously pristine environments.
 

How can superconductors help?

• The use of HTS cable systems eliminates the need for visually-intrusive overhead line infrastructure. Furthermore, the rights of way required for new HTS cables are extremely narrow – typically, corridors are only a metre wide. Cables are direct-buried, with no need for pipes or tunnels.

• Undergrounding overhead lines holds out the prospect of releasing land for new commercial and industrial uses. As already noted, the beauty of using HTS cable systems is that the right of way required is extremely narrow – typically around one metre. By contrast, the cable swathe required with conventional copper and aluminium circuits is sometimes more than 60m wide.

#3. Cost and Investment of Renewable Electric Grid Security: Action today can secure grids for the future

Regulations need updating for new grid deployment and better asset utilisation. Grid regulation should incentivise grids to keep pace with the rapid changes in electricity demand and supply. This entails addressing administrative barriers, rewarding high performance and reliability, and fostering innovation. Transmission and distribution grid planning must align with government long-term plans.

While new grid infrastructure takes 5 to 15 years to complete, new renewable projects take one to five years and EV charging infrastructure less than two years. Grid plans should integrate inputs from long-term energy transition plans across sectors, anticipate and support the growth of distributed resources, connecting resource-rich regions including offshore wind, and link with other sectors including transport, buildings, industry, and fuels such as hydrogen. 

Building out grids also requires secure supply chains and a skilled workforce. Governments can support the expansion of supply chains by creating firm and transparent project pipelines and by standardising procurement and technical installations. They also need to build in future flexibility by ensuring interoperability of all the different elements of the system. 

HTS cable systems allow for sustainability and performance : combining efficiency with environmental responsibility whilst ensuring economic sustainability and performance

The high current density, which can be transmitted in a comparatively small cross-section, makes it possible for the cable routes to be significantly narrower with the same capacity.

The line width is a very important issue in the construction of power lines for several reasons. For example, it is often not possible to retrofit or upgrade conventional routes in conurbations due to space constraints, but a superconducting route can be realised due to its small space requirement. This was demonstrated as an example in the SuperRail project - this project illustrates perfectly how their compact nature enables them to transport very high power through a limited space.

Superconductors are also justified in rural areas. The narrow line width limits the impact on the natural environment. Particularly in sensitive natural areas, superconductors offer an ecologically better alternative to the large number of conventional cable routes that are required to connect offshore wind farms. 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.

In addition, reduced cable route widths are also advantageous in terms of right of way and public acceptance.

How superconducting systems can help overcome these challenges

En outre, la supraconductivité à haute température présente des avantages économiques non négligeables. Ces technologies ont en effet permis d’économiser quelques millions d’euros sur de nombreux projets, des économies favorisées par des coûts d’investissement réduits par rapport à des câbles conventionnels en cuivre ou aluminium. Même si des facteurs tels que localisation et complexité peuvent influer sur les coûts associés aux projets, la technologie HTS permet de surmonter les difficultés liées aux droits de passage, assurant une transmission efficace de la haute tension à des niveaux de moyenne tension. En raison de la raréfaction croissante et de l'augmentation des coûts des matières premières telles que le cuivre et l'aluminium, la viabilité économique de la technologie supraconductrice est appelée à s'améliorer.

Des millions d’euros sont investis chaque année par les acteurs de la technologie supraconductrice, y compris les conducteurs avancés tels que les fils HTS, en vue d’augmenter les capacités industrielles et améliorer leur compétitivité en optimisant les coûts des composants.

#3. Partenariat industriel pour favoriser l'innovation et proposer des technologies plus avancées 

La conférence a mis en évidence l'importance des collaborations internationales pour accélérer l'innovation dans le secteur ferroviaire et au-delà. De nombreux projets et initiatives visent à développer les technologies supraconductrices. Ces projets ne se limitent pas à l'industrie ferroviaire et profiteraient à d'autres secteurs, parmi lesquels:

• L'éolien en mer : la technologie HTS (Supraconductivité à Haute Température) transforme les projets de parcs éoliens offshore. Le consortium SupraMarine (RTE, ITP, Nexans et un leader mondial des systèmes de refroidissement Cryogéniques) développe un câble d'export supraconducteur HT AC de 100 km qui devrait permettre de réduire les coûts associés au projet, l’objectif annoncé étant une réduction d’environ 1 milliard d'euros pour un projet éolien offshore de 2 GW.
   
• SuperNode ltd, en Irlande, développe une solution en courant continu haute tension supraconductrice permettant d’améliorer l’efficacité de l’industrie en augmentant les capacités de transmission d’énergie à des niveaux que les câbles conventionnels ne peuvent atteindre. 
   
• Aérospatiale : Airbus a fait part de sa feuille de route pour un vol sans émissions, dans laquelle les câbles supraconducteurs jouent un rôle essentiel. S'appuyant sur le projet ASCEND, l'initiative CRYOPROP vise à poursuivre le développement des technologies supraconductrices pour favoriser une aviation plus propre.
   
• Industrie : d'éminents universitaires ont présenté leurs recherches visant à faire progresser la supraconductivité dans l'industrie et ont confirmé le potentiel de cette technologie, notamment dans le domaine du transport et de la distribution d'électricité.

Les applications potentielles de la technologie supraconductrice présentent des opportunités significatives dans divers domaines. L'industrie des fils supraconducteurs investit massivement pour répondre à la demande croissante de câbles supraconducteurs. De nouvelles capacités de production visent à réduire les coûts des fils par un facteur de quatre en utilisant des processus industriels avancés