Roadmap Paper Shows How Superconductors Can Decarbonise Transport Sector

Leading researchers from academia and industry have contributed to a new ‘roadmap’ paper which examines how the transport industry, which creates around a quarter of energy-related carbon emissions, could accelerate the adoption of electric power at scale by embracing superconducting tech.

It also sets out the challenges which still need to be overcome over the next decade in order to maximise potential climate benefits.

The roadmap, commissioned by the Institute of Physics and published in the Tier one journal in the field, Superconductor Science and Technology, was led and edited by Dr Wenjuan Song of the University of Glasgow.

The roadmap is the result of an international, interdisciplinary and cross-sector collaboration which brought together more than 60 researchers and engineers from over 40 companies, universities and research institutes worldwide, including transport giant Airbus.

Through 26 expert perspectives, it charts how superconductivity could unlock transformative advances across aviation, rail, marine and space and shape the future of sustainable transport.

Superconductors are a special class of materials which can transport electricity with almost no resistance and zero loss when cooled to cryogenic temperatures near absolute zero to up to 90 degrees Kelvin. Although they were discovered a century ago, their challenging operational requirements have largely restricted them to use in bulky, terrestrial, stationary technologies like MRI scanners.

Recent technological advances, however, are making superconducting devices smaller and lighter. Superconductors could deliver more power and torque in smaller, lighter packages, increasing the efficiency of aircraft motors, ship propulsion, rail transformers and spacecraft magnets in the years to come. In some cases, such as hydrogen-powered aircraft, liquid hydrogen could potentially be used as both fuel and coolant, which could help to maintain the required temperature to maximise the efficiency of some designs.

The James Watt School of Engineering’s Dr Mohammad Yazdani-Asrami is the paper’s second author alongside Dr Song. He said, “Encouraging the adoption of a new technology by industry is a chicken-and-egg problem, but we’ve seen with the rapid expansion of solar power in recent years that tipping points towards greener energy can and do happen.

“Superconductors need the same three things that solar power had in order to reach that tipping point: better materials, cheaper materials, and a willingness from industry to adopt them. This roadmap makes a convincing case that superconducting tech is already proving its worth for transport, and that the next 10 years of focused advances and further private and public funding will be crucial in enabling us to reach the point where superconductors become practical for use across the transport industry and beyond.”

Aviation, one of the hardest engineering challenges for decarbonisation, is one of the key focuses of the roadmap. Aircraft account for around 2% of the world’s transport-related carbon emissions today, but if emissions keep rising as projected with the increased scale-up of national and international flights, they could reach between two and four times their 2015 level by 2050.

The main obstacle to electrifying flight has always been weight: today’s electric motors deliver between five and 10 kilowatts per kilogram, which is too heavy for medium/large aircraft. Superconducting machines currently in development, however, are expected to deliver between 20 and 40 kilowatts per kilogram, helping to overcome one of the major barriers for building emission-free electric aircraft.

Dr Wenjuan Song, of the University of Glasgow’s James Watt School of Engineering, is the paper’s main editor and corresponding author. She said: “Electric aircraft don’t have to be a dream any more. This roadmap shows the pathway to commercially available aircraft flying with net-zero emissions, setting out the components needed, from the powertrain and motors to cables and fault-current limiters, alongside system-level integration.

“Real hardware has already started to approach maturity. Airbus’s ASCEND project powered on a 500-kilowatt superconducting and cryogenic powertrain in late 2023, and their Cryoprop demonstrator is nearing completion. With their ZEROe programme continuing to develop, that future is genuinely coming into view. We expect the next decade will see further advances which will help encourage widespread commercial adoption.”

Maritime shipping is the largest single source of transport carbon in the roadmap’s breakdown, at around 3.5–4% of global emissions. Superconducting motors in development offer lighter, highly efficient propulsion, and the heaviest-duty demonstrator in the entire roadmap is already built: a 36.5-megawatt superconducting ship-propulsion motor tested by the US Navy.

Superconducting cables can knit together all-electric ship power systems exceeding 100 megawatts, and when liquid hydrogen becomes a marine fuel, its deep cold can help cool key components of the system, potentially paving the way to the first generation of zero-emission vessels.

Rail, meanwhile, is already among the most efficient and least polluting forms of transport. While it produces around 1% of transport-related carbon today, demand is set to grow steeply, so further gains still matter.

The roadmap highlights real-world examples, including a Chinese high-speed train programme that has demonstrated a superconducting traction transformer operating at over 99% efficiency and half the weight of conventional systems.

Superconducting power cables have also been installed on railways in Japan and France. Looking further ahead, superconducting maglev trains have reached around 600 km/h in Japan, while China is developing vacuum-tube systems targeting speeds of up to 1,500 km/h.

In space, superconducting magnets can enable more powerful thrusters from smaller, lighter hardware. Frictionless superconducting bearings promise no contact, wear or lubrication, making them fail-safe. They could let satellites spin faster, weigh less and operate reliably for decades. The quantities of material involved are tiny, making space a high-value niche for the technology rather than a mass market.

The potential climate benefits of widespread adoption of superconductors across the transport industry are significant. If 50% of the transport industry adopted superconducting tech, it could help save around 23 gigatonnes of carbon emissions across a 25-year period, according to an article contributed by Faraday Factory Japan, a leading manufacturer of superconducting wire. The same analysis notes that the price of the material required to achieve this already sits below the value of the emissions it could save.

There are still barriers to adoption. Cost, better superconductors, cooling systems, protection schemes, and engineering complexity are the key hurdles to overcome as the technologies outlined in the roadmap work their way up the technology readiness scale and journey from the lab to market.

Dr Song added: “We chose to collect reflections from as wide a range of expertise as we could in order to provide a clear research agenda for the next two decades, and we believe we have created a comprehensive set of guidelines.

“We’ve also delivered a clear message to industry: the technology is viable, several applications are approaching commercial readiness, and the long-standing objection that superconductors are too hard to cool are being overcome at last. It’s time to get on board and set a course to decarbonise the transport industry.”

The paper, titled ‘Roadmap to Electrification of Transportation‘

‘Systems Enabled by Superconducting Technology‘ is published in Superconductor Science and Technology. The research was supported by funding from the Engineering and Physical Sciences Research Council (EPSRC) and the European Union’s Horizon programme and many other national and international funders.