[dtquad]

For the most valuable applications it is also "good enough" to find a superconductor that can be cooled with cheap liquid nitrogen and retain the magnetic field tolerance, current-carrying capacity, and thermal stability of a superconductor cooled with expensive liquid helium.

Some so-called "high temperature" superconductors begin superconducting at liquid-nitrogen temperature or higher. However in real life applications like MRI and particle accelerators it turned out that they still need to be cooled with much colder liquid helium to get the desired magnetic field tolerance, current-carrying capacity etc. Finding a high-quality liquid-nitrogen-grade superconductor with these desired properties would be a revolution in itself.

[nine_k]

Mechanical properties are very important, too. Able to bend, able to be cut, able to withstand mild shocks and vibration without fracturing. Something you can make actual wires from, at least at some stage. This, superconducting at liquid nitrogen temperature, would produce a revolution. Transmission lines alone would be huge.

[jmyeet]

> Transmission lines alone would be huge.

Transmission lines are a great example of competing demands. Copper is a better conductor so why do we use aluminium? Because of weight. And weight is a huge factor in supporting large cables over long distances.

Metals are also ductile, which is important for a cable to hang in gravity under its own weight, be moved by the wind and so on. Assumedly exotic crystals wouldn't have this property. Even if they could, what would the weight be? Would the cross-section need to be much larger? Particular to this family of superconductors, tungsten isn't exactly the easiest thing to do deal with, particularly on a massive scale.

There's an interesting Reddit thread about this topic [1]. One issue it raises is we'd need to essentiaally rebuild our entire infrastructure and transformers are a big part of that.

Personally, I think energy is going to get an awful lot more local. Solar is our future (IMHO). The ability to store excess power generated during the day and then use it when it's dark or cloudy will obviate the need to expensive long-line transmission infrasturcture from distant power plants.

Lastly, the GP is correct: liquid nitrogen is incredibly cheap. It's basically the cost of drinking water. Getting something we could use at liquid nitrogen cooling temperatures would be incredibly impactful.

[1]: https://www.reddit.com/r/AskPhysics/comments/12etlkr/wouldnt...

[nick3443]

Cheaper batteries meeting the storage requirements for renewables would be a game changer!

[astrange]

We're getting that.

https://www.caiso.com/documents/2023-special-report-on-batte...

[nine_k]

I suppose that power lines may start looking more like pipelines. These can be above-ground is the actual piping is not heavy, on lower pylons with a reduced span. Liquid nitrogen is lighter than water, does not need high pressure, and the insulation is mostly styrofoam.

The voltage can be substantially lowered, because high currents don't lead to high losses; the current may be made as high as practical, near to the limit of the material's superconducting state.

[zahlman]

>Lastly, the GP is correct: liquid nitrogen is incredibly cheap. It's basically the cost of drinking water.

Hold on, what? How?? Reaching that temperature seems like a difficult task; and what's used as a source of pure nitrogen, anyway? Is there some clever trick to separating it out from the air?

[BurningFrog]

Maybe superconducting transmission lines need to be underground

[popol12]

How would we cool transmission lines to liquid nitrogen temperature?

[yencabulator]

https://www.youtube.com/watch?v=3gFUwGedayw

[anyfoo]

> Transmission lines alone would be huge.

Or small! :D

[nine_k]

But either way freezin' cool!

[BariumBlue]

I know we've got cuprates, superconductors formed with copper oxide, useful up to 133Kelvin, higher than Nitrogen cooling's capability of 77K.

I've read of them being used in wind turbines and particle accelerators, as well as concepts for fusion reactors.

Your comment makes it sound like they have insufficient field tolerance / current characteristics though. I don't think I've heard about Cuprates at all recently.

[throwup238]

Cuprates are also brittle ceramics so they’re difficult to shape and larger pieces and assemblies tend to run into issues with grain boundaries that interfere with superconductivity, so there’s a lot of practical issues. The classic superconductors are very low temperature but are much easier to cast.

[FredFS456]

There's a few fusion startup companies using superconducting ReBCO tape to make their magnets. From the results that they're getting, I think we've largely cracked the engineering problems of making "wire" from ReBCO and it's largely just a scaling game now. I do want to point out that they're still cooling with liquid hydrogen at ~20K for high current capacity though.

[cyberax]

I invested in a couple of fusion startups (because why the hell not?), and the word on the street is that flexible tapes/wires are still not a solved question. Nobody can make them with consistent quality in large enough batches.

[dtgriscom]

Data point: liquid nitrogen is cheaper than milk.

[jmward01]

How interesting..... Of course liquid nitrogen + milk (with one or two other things) is worth more than the sum of its parts.

[nharada]

Yeah, haven’t you seen how much they charge for Dippin Dots??

[nick3443]

How can we take advantage of this to reduce my grocery bill? :)

[saagarjha]

I mean it’s literally selling air :P

[Panzer04]

For the most valuable applications, sure - but a lot of the biggest historical advances came not from the first application of that new tech, but from that new tech becoming cheap and ubiquitous.

Maybe (cheap) room-temp superconductors won't actually be that interesting (maybe it just increases energy transmission efficiency 5-10%), but perhaps it's availability catalises a whole range of new applications that were never considered before.

[raelming]

If room temperature superconductors existed that were practical for transmission scale wires, it would be possible to make a global superconducting electrical grid. The middle East could fill their desert with solar panels and export that electricity to Europe. The sunny side of the planet could export solar power to the nighttime side of the planet. You could make electrical motors out of it a fraction of the size of current motors, like 1000 of horsepower out of a soda can, which would revolutionize the design of pretty much everything in the world with moving parts. Mechanical transmissions would go the way of the vacuum tube. Any vehicle or ship that's not completely electrified would be hybrid electric at least. You could also miniaturize transformers which has a lot more implications for making everything that uses a lot of power to be much more powerful and cheaper.

[NL807]

>and retain the magnetic field tolerance, current-carrying capacity

Even if it doesn't meet those requirements, room temperature superconductors will have immense value in low-power applications, micro electronics, sensing, etc.

[kulahan]

>to get the desired magnetic field tolerance

Interesting, then, that the article actually mentions a superconductor that got stronger in the presence of a magnet! Wild things we're learning here!