Where Superconductors Are Actually Used: From Power Grids to Fusion
Part 5 of our Superconductor 101 series. Earlier parts: what superconductivity is, the materials, cable construction and tape manufacturing.
Superconductors have a reputation for being perpetually five years away. In fact they have been working quietly in the field for decades. The first industrial HTS cable was energized in 2000, and the range of applications has kept widening since. This article tours the places superconductors actually earn their keep, each grounded in real projects from our tracker.
Urban power cables: more grid in the same trench
The strongest business case for HTS cables is space rather than saved energy. In dense cities, the scarce resources are duct space, trench corridors and substation real estate, and this is where zero resistance pays.
Because an HTS cable carries several times the current of a copper cable the same size, it can deliver bulk power at distribution voltage instead of transmission voltage. Shenzhen’s 400-metre cable moves 43 MVA at just 10 kV, the delivery of a conventional 110 kV line, which means a city can skip building a downtown high-voltage substation and its transformers entirely. The same argument drives Munich’s planned SuperLink: 15 km at 110 kV instead of a new 380 kV corridor into the city centre. If built, it will be the world’s longest superconducting cable.
The concept is well proven by now. Essen’s AmpaCity cable replaced a 110 kV copper link with a 10 kV HTS one and ran seven flawless years. Shanghai’s Xuhui cable (1.2 km, 35 kV) has fed a downtown district commercially since 2021. KEPCO’s Shingal–Heungdeok line in South Korea became the world’s first superconducting cable in commercial utility operation in 2019 and is still energized. The lineage runs back through LIPA’s 138 kV transmission cable (2008) to Southwire’s 30-metre industrial feed in Georgia (2000). Newer entrants like VEIR are attacking transmission itself, with passively cooled overhead HTS lines aimed at data-centre-scale loads. All of these are rows in the tracker.
There is a bonus feature, explained in Part 3: cold-dielectric HTS cables have essentially no external magnetic field. That eases routing through crowded corridors, past sensitive equipment, and through neighbourhoods where electromagnetic fields are a planning objection.
Fault current limiters: the self-resetting fuse
One superconducting device has no conventional equivalent at all. A superconducting fault current limiter (SFCL) exploits the sharp transition described in Part 1. In normal operation it is a superconductor, sitting invisibly in the circuit with near-zero resistance. When a short-circuit fault slams thousands of extra amps through it, the surge itself pushes the material past its critical current: it quenches, becomes resistive within milliseconds, and throttles the very fault that triggered it. When the fault clears, it cools back down and resets.
A self-triggering, self-resetting, passive circuit breaker is something grid engineers otherwise simply don’t have, and it grows more valuable as grids interconnect and fault currents rise. Essen’s AmpaCity project deployed an SFCL protecting its cable; see the tracker.
Fusion: the application that changed the industry
For decades, fusion magnets meant low-temperature superconductors (ITER’s giant coils are Nb₃Sn). What REBCO changed is field strength. Run at around 20 K, REBCO tape carries huge currents in magnetic fields beyond anything LTS materials survive (Part 2 explains why).
This matters because a tokamak’s power output scales steeply with magnetic field, roughly with its fourth power, so doubling the field lets a much smaller and cheaper machine reach the same plasma performance. That is the entire premise of Commonwealth Fusion Systems’ SPARC tokamak in Massachusetts: 20-tesla REBCO toroidal field coils, the world’s highest-field fusion magnets, with the first of eighteen installed in January 2026 and first plasma targeted for 2026–27.
Fusion’s impact reaches beyond fusion. SPARC’s magnet programme made it the largest commercial consumer of REBCO tape to date, pulling manufacturers into real mass production and pushing wire prices down for cables, generators and everything else (Part 4 explains why volume is what cuts tape cost).
Rotating machines: lighter generators and motors
In a generator or motor, superconducting windings mean far stronger magnetic fields in far less iron and copper, so the machine shrinks and lightens dramatically. The sweet spot is anywhere weight is money: at the top of a wind turbine tower, or aboard a ship or aircraft.
The flagship demonstration is in the tracker. EcoSwing, the world’s first superconducting generator to drive a commercial wind turbine, spun a 3.6 MW direct-drive generator in Denmark from 2018, coming out about 40% lighter than the permanent-magnet equivalent and using drastically less rare-earth material. That last point is strategic: direct-drive wind turbines are among the biggest consumers of rare-earth magnets, and superconducting designs largely sidestep that supply chain.
Railways, maglev and DC feeds
Rail has two superconductor stories. The famous one is maglev, in which superconducting magnets aboard the vehicle levitate it over the guideway. This is the approach behind Japan’s record-holding SCMaglev programme, built on LTS magnets with HTS versions under test.
The nearer-term story is more practical: feeding power to ordinary electric railways. DC rail networks move enormous currents at modest voltage, which is exactly a superconductor’s favourite regime, and substation capacity limits how many trains can run. In Paris, the SuperRail project is installing HTS cables at Montparnasse station (a world first) to reinforce the 1,500 V DC traction supply, at 3,500 A per cable, without building new substations. Details in the tracker.
Big science: the established market
Long before power grids, superconductivity’s commercial anchor was magnets for science and medicine, and it still is. Tens of thousands of hospital MRI machines rely on NbTi magnets in liquid helium; MRI remains the largest superconductor market of all. Particle accelerators bend their beams with superconducting magnets, and the LHC’s ring is NbTi at 1.9 K.
HTS-era materials are now migrating into this world too, and the tracker captures a milestone: CERN’s High-Luminosity LHC links, flexible cryostats each bundling 19 MgB₂ cables rated for a combined 120,000 amps, will feed the upgraded collider’s magnets. Over 1,000 km of MgB₂ wire has already been produced for them. Cheap conductor, helium-gas cooling, and currents no copper busbar could dream of.
What to watch next
Reading the tracker as a whole, a few patterns stand out:
- From demonstrations to commerce. Early rows are 30–600 m proofs of concept; recent ones are commercial multi-year operations (Shanghai, Yongin, Chicago) and infrastructure-scale plans (Munich’s 15 km).
- Fusion demand is the flywheel. Every kilometre of REBCO ordered for magnets makes tape cheaper for cables and generators.
- New frontiers keep opening, including liquid-hydrogen-cooled MgB₂ cables for renewables (the EU’s SCARLET project), superconducting links for data centres and electric aircraft, and grid standards work (the UK’s SuperNode and National Grid partnership) that signals utilities preparing for adoption at scale.
The tracker exists to follow exactly this build-out, project by project, with sources for every row. Explore the full table, and if you are new to the field, the series starts at Part 1: What is a high-temperature superconductor?