High-temperature superconducting magnets and the manufacturing bottleneck

High-temperature superconducting (HTS) magnets are bottlenecks in modern technology. The demand for them is growing fast. But the industrial capability to manufacture these magnets at scale doesn’t exist yet.

(Picture: MIT News)

Most people think about magnets as the things on their fridges. But over the last decade magnets have quietly become one of the most strategically important materials on the planet. The clean energy transition runs on them (e.g. in wind turbines or electric vehicles). Most of the magnets people talk about in this context are permanent magnets, materials whose atoms have been permanently aligned to produce a fixed magnetic field. For them there is no power needed and no moving parts. The problem is that making them requires rare earth elements. And as the world has woken up to how dependent it is on China for the rare earth materials that go into these magnets, the conversation has gotten louder and more urgent.

But there is another type of magnet that deserves attention. One that works on completely different principles, uses different materials, and makes things possible that permanent magnets simply cannot do: superconducting magnets. They are a type of electromagnet made from coils of superconducting wire, cooled to cryogenic temperatures during use. Because the wire has no electrical resistance in its superconducting state, it can carry far larger currents than a conventional electromagnet (magnetic field strength is directly proportional to current). The result is extraordinary field intensity.

I. (High-Temperature) Superconducting Magnets and what they are

Superconductivity was first observed by Heike Kamerlingh Onnes in 1911. It describes the phenomenon where a material conducts electrical current with zero resistance below a certain critical temperature, due to the formation of electron pairs that move through the material without scattering or energy loss.

In a normal conductor like copper, atoms are constantly vibrating. As electrons move through, they collide with those vibrating atoms, creating resistance that bleeds off as heat, which is why power lines lose energy over distance, and why wires get warm under load.

In a superconductor, this works differently. If you cool the material down far enough, the atomic vibrations almost stop completely. Electrons can then move through in perfect synchrony. Nothing scatters them and nothing slows them down. Because there is no resistance which means that no energy is lost as heat.

When that happens, something remarkable becomes possible: A current running through a loop of superconducting material will keep going indefinitely without a power source. If you wind that into a coil, you get a magnetic field of extraordinary strength, far beyond what any permanent magnet or conventional electromagnet can produce at the same size.

The challenge is temperature. Most superconductors only work below around 9–10K (-264°C to -263°C), extremely close to absolute zero. Achieving that requires liquid helium, which is expensive, difficult to handle, and in limited supply. For decades, this made superconducting magnets a laboratory curiosity rather than a practical technology.

That’s where high-temperature superconductors (HTS) came in. “High temperature” is still cold by any normal measure (-183°C to -253°C), but warm enough to use standard cryocoolers instead of liquid helium, and warm enough for the magnet to sustain a higher magnetic field.
Strong enough to confine plasma in a fusion reactor and strong enough to enable applications that are simply out of reach for any permanent magnet or conventional electromagnet.

Important take away:

High-temperature superconducting magnets represent a significant step forward from earlier superconducting technology. The ability to operate at warmer temperatures and without liquid helium makes them considerably more practical.

II. HTS use cases:

There are many examples for areas that are dependent on high temperature super conducting. The main ones here to consider are:

Fusion energy, which is probably the most obvious case. Every fusion company right now is trying to build superconducting magnets. These are enormous, precision-engineered objects. Some are two metres across, carrying currents of 40,000 amperes or more. They’re currently hand-built, one at a time, by specialists at national laboratories. So far there is no commercial manufacturer that can produce them reliably, quickly, or at anything approaching industrial volume.

Quantum computing is another area where HTS magnets are becoming relevant, though in a more specific way than fusion. Quantum computers operate at extremely low temperatures (around 10 millikelvin, which is even colder than most superconductors require). Getting to those temperatures requires specialised refrigeration systems, some of which depend on superconducting magnets. Adiabatic demagnetisation refrigerators, for example, use superconducting magnets to reach the millikelvin range that quantum processors need to function. The supply chain for these components is thin and lead times are long. As quantum computing scales, demand for the cryogenic infrastructure that makes it possible will grow with it.

Data centres are a less obvious entry but worth paying attention to. AI workloads create power demand that surges and spikes unpredictably. A GPU cluster ramping up can draw massive amounts of current within milliseconds, which destabilises local grid connections and creates serious thermal management challenges. This is where HTS technology becomes relevant. Superconducting magnetic energy storage systems can absorb and release that energy almost instantly, acting as a stabilising buffer between the grid and the compute infrastructure.

Power grids face a similar challenge at a larger scale. Conventional cables lose around 5–8% of electricity to heat over long distances. That sounds small but adds up to an enormous amount of wasted energy across a national grid. Superconducting cables lose almost nothing in transmission and can carry far more current in a much smaller physical footprint. HTS-based fault current limiters can also respond to grid failures in milliseconds, preventing the kind of cascading blackouts that ageing infrastructure is increasingly vulnerable to.

Important take away:

The applications outlined above represent only a fraction of the sectors where high-temperature superconducting magnets are expected to play a significant role. Across fusion energy, quantum computing, data centre infrastructure, and power grids alone, the addressable market is substantial and growing.

III. The manufacturing problem:

The best HTS material available today is REBCO (Rare Earth Barium Copper Oxide). It carries 1,000 times more current than copper at the same size, produces magnetic fields above 20 Tesla (for context, an MRI machine runs at 1.5 to 3 Tesla) and works without liquid helium.

REBCO is produced as a thin, flexible tape rather than wire, which makes it possible to wind into coils. But it also makes manufacturing extremely precise and technically demanding work.

The issue is that HTS magnets are still essentially artisanal objects and very often wound by hand, by specialists who’ve spent careers developing the skill. The REBCO tape must be wound at exactly the right tension, with exactly the right geometry, at nanometre-level precision throughout. A small error anywhere in the coil can cause a quench.

A quench is when the magnet abruptly loses its superconducting state and releases all its stored energy at once. If you don’t detect it within milliseconds and safely dump that energy, the magnet destroys itself. Uncontrolled quenches are expensive, dangerous, and the reason HTS magnets have historically been too fragile for commercial use at scale.

The people who know how to build these things reliably mostly work at national laboratories (Brookhaven, CERN, ITER, the National MagLab). All of them are extraordinary institutions, but not built to serve commercial customers at volume.

The commercial result: lead times of 12–18 months per unit, poor repeatability, variable quality control. Global production of research-grade superconducting magnets sits at roughly 300 units per year. Costs run $35,000–$150,000 per unit for smaller systems, far more for large ones.

Important take away:

REBCO currently represents the most capable material available for high-temperature superconducting applications. However, material performance alone does not determine commercial viability. The more significant challenge lies in developing the manufacturing processes required to produce HTS magnets reliably, consistently, and at the volumes that industrial demand requires.

IV. What a solution could look like

The companies working seriously on this problem share a common insight: you can’t solve HTS magnet supply by doing more of the same, faster. You have to industrialise something that has never been industrialised.

That means several things in practice.

• Automated coil winding
  Replacing hand-winding with robotic systems capable of nanometre-level precision. This is technically demanding, the tolerances are tighter than almost any other manufacturing process, but it’s the only way to get from bespoke objects to repeatable products. Companies building their own automated winding machines are developing a manufacturing capability that doesn’t exist elsewhere.
  

• Solving quench protection
  The companies making the most progress here are developing systems that detect a quench spot within seconds and dump the stored energy safely in under 10 milliseconds, fast enough to protect the magnet from damage. The approaches vary: non-insulation winding technology, which reduces temperature gradients during a quench; active monitoring systems with rapid response; and novel coil geometries that distribute energy more safely. This is where the most defensible IP sits.
  

• Dry conduction cooling
  Eliminating liquid helium entirely, using closed-cycle cryocoolers to reach operating temperature. This matters both for cost, liquid helium is expensive and logistically difficult, and for scalability, since you can’t build thousands of quantum systems or dozens of fusion reactors if each one requires a continuous supply of a rare cryogen.

• The integrated system model.
  Historically, a research lab building a superconducting magnet system would source coils from one supplier, power electronics from another, a cryogenic system from a third, and stitch them together in-house. For a national lab, this is fine. For commercial customers who need reliable, warrantied products they can deploy and service, it’s a nightmare. The companies building integrated turnkey systems, magnet, power electronics, cooling, quench protection, all from one source, are doing something commercially new.
  
  

• Design software.
  Magnet design has historically required weeks of specialist calculation to go from requirements to a viable coil geometry. Purpose-built simulation software that handles magnetic field calculation, mechanical stress analysis, and quench simulation in hours rather than weeks is a significant multiplier on both design speed and the pool of engineers who can do this work.

V. The bottom line

The market for HTS magnets is large but the manufacturing capability doesn’t exist yet at commercial scale. This is exactly where the investment opportunity lies.