The UK's drive to net zero won't succeed on wind turbines and solar farms alone. The real bottleneck is moving that clean electricity from remote fields and offshore platforms to the homes, cities and industries that need it.
However, a report co-authored by researchers from the University of Cambridge highlights a technology that could change the game: high-temperature superconducting (HTS) cables.
The UK is a world leader in offshore wind. But transmitting electricity from the North Sea to the Midlands and south, without losing much of it along the way, is a growing technological and political challenge.
With their ultra-high power density and near-zero losses, HTS cables could be a solution. They can carry vast amounts of electricity underground, quietly, and efficiently, without the need for overhead transmission lines.
"The real attraction of superconducting transmission is that it allows us to carry more electricity, over longer distances, without wasting energy or disrupting the environment," said Professor Tim Coombs from Cambridge's Department of Engineering, a co-author of the report, commissioned by the Institute of Physics (IOP).
Traditional aluminium cables strung from pylons lose between 5% and 10% of the electricity they generate as heat. For the UK, that adds up to 25 terawatt hours a year - energy worth around £3.75 billion annually.
HTS cables, cooled by liquid nitrogen, have no electrical resistance. They can deliver electricity generated hundreds of miles away without waste, turning what is currently a massive cost into a massive saving.
Additionally, a single buried HTS cable can carry the same amount of power as multiple aluminium or copper overhead or underground lines. In urban areas where land is scarce, this density makes a huge difference: far fewer trenches or rows of pylons are needed. And because the cables can be buried, the visual impact on the countryside is minimal.
For consumers, this means preserving landscapes while still connecting to renewable power. For industry and government, it means removing bottlenecks that threaten the grid as different sources of energy come online.
"Grid bottlenecks sometimes force operators to curtail generation, wasting clean power," said Coombs. "HTS cables could act as low-loss 'superhighways' to move renewable energy exactly where it's needed. They could also be used to feed the output of large solar farms straight into the grid, without the need for long new transmission lines. HTS makes every unit of clean electricity count - reducing reliance on fossil fuels and easing the need for costly new power stations."
Although initial investment costs for HTS cables are higher than for aluminium lines, the savings from reduced energy losses, greater grid reliability, and avoidance of new fossil-fuel generation more than offset these expenses over time.
Coombs and his colleagues specialise in turning the theory of superconductivity into viable engineering designs. They have worked on the fabrication of defect-free HTS tapes, improved cryogenic cooling systems, and developed new methods for integrating HTS with existing high-voltage alternating and direct current (HVAC and HVDC) grids.
"Cambridge research has always combined fundamental discovery with practical application," said Coombs. "In superconductivity, that means moving from the lab bench to systems that can really carry the nation's power."
Other nations are already demonstrating HTS technology at scale: projects in Germany (AmpaCity), the US, Japan and China have shown that superconducting cables can operate reliably in live grid environments.
With electricity demand expected to rise sharply due to the electrification of transport and heating, the UK risks being left behind unless it acts quickly to move from research prototypes to substantial field trials.
The IOP report highlights the need for major UK demonstration projects - a buried HTS transmission link capable of handling real grid demands. Such a trial would not only prove performance and reliability but also help establish standards and build supply chains for this emerging industry.
"This should be treated as a national priority," says Coombs. "A field trial on British soil would place us at the forefront of a technology set to grow globally over the next half-century. The benefits are not just environmental - they are industrial and strategic too, helping the UK bridge the gap between promising prototypes and full-scale deployment."
If the UK develops HTS transmission technology successfully, there may be opportunities to supply components and expertise to international projects, such as the European Supergrid and Asian renewable networks.
British-made superconducting cables, fault current limiters, and associated cryogenic systems could find niche markets abroad, supporting high-value jobs and the UK's manufacturing base.
As countries expand renewable energy and look to reduce carbon emissions, demand for efficient, low-loss transmission is expected to grow. HTS technology could offer solutions and potential new markets over the coming decades.
For the government, HTS represents a way to meet climate targets more affordably by reducing the need for additional generating capacity. For the electricity supply industry, it promises greater efficiency and resilience in the face of rising demand. And for the public, it means protecting landscapes while cutting bills and carbon.
"Superconducting transmission is not a futuristic dream - it is a practical solution to today's challenges," said Coombs. "By investing now, we can secure energy security, lower costs, and ensure the UK leads in a technology the world will soon need."
Tim Coombs is a Fellow of Magdalene College, Cambridge.
