[amaterasu]

Would be interesting to see the actual cost differential in this vs permanent magnets.

They don't go into details about the cost of fabricating the HTS, but gadolinium is less than half the cost (in oxide form) of neodymium according to the article, and it uses 1/1000th the amount.

[londons_explore]

Main cost of neodynium:

* Magnets themselves

* Support structure for a heavy generator

* Energy 'iron losses' in magnet hysteresis.

Main costs of superconductors:

* Superconducting material

* Upfront cost of chillers

* Energy loss in chillers.

For bigger and bigger turbines, superconductors will always win, since the material is cheaper, and chiller cost and energy loss scales with the power generated ^ (2/3), whereas the support structure needs to be both taller and stronger so scales with ^(3/2), so superconductors always ends up eventually cheaper.

[GoMonad]

Can you explain where the 2/3 and 3/2 powers come from?

[londons_explore]

Chiller cost is approximately proportional to the surface area of the generator. The power output of a generator is approximately proportional to the volume.

The mass of a generator is approximately proportional to the volume too. The support structure is proportional to the mass of the generator, times the height of the turbine (actually more than that, but we'll ignore that for now).

The height of the turbine is proportional to the square root of the wind energy collected. (turbine blades can't hit the ground)

Combine all those factors to get the power indices...

[tigershark]

I think it’s just a publicity stunt. There is no way that this wind turbine will be more profitable than a normal one given the pretty crazy cooling requirements. Also I don’t really understand why they chose that kind of superconductor that apparently has to be cooled to -240 when there are other superconductors that need to be cooled to just 150K...

[starbeast]

>There is no way that this wind turbine will be more profitable than a normal one given the pretty crazy cooling requirements.

As long as the insulation method for the superconductor is good, once it is cool, keeping it cool should use surprisingly little energy, especially compared to the output of one of these things.

>Also I don’t really understand why they chose that kind of superconductor that apparently has to be cooled to -240 when there are other superconductors that need to be cooled to just 150K...

They do the same for a lot of the SMES systems - https://en.wikipedia.org/wiki/Superconducting_magnetic_energ... - Apparently the difference in cooling costs isn't that much and there are a variety of benefits to using the low temp ones that more than offsets that cost.

*edited to correct brainfart

[Iv]

> Also I don’t really understand why they chose that kind of superconductor

The fact that it can be manufactured as a flexible cable is probably key there. You not only need superconducting materials, you need a coil of it.

[dagw]

here are other superconductors that need to be cooled to just 150K

Don't those very high temperature super conductors only work under under extremely high pressure?

Also most higher temperature super conductors are very tricky to produce in larger quantities.

[tigershark]

Honestly I don’t know about the 150K one, but if I remember correctly the cuprates didn’t need high pressures.

[londons_explore]

The ceramic ones aren't flexible, which is tricky when you're using it like a wire and need to wrap it around stuff...

Also, they can't be joined, so you have to do significant redesigns of the machine to be able to get the whole conductor in in one piece.

[tigershark]

It makes sense, thanks, I didn’t think about flexibility.

[jacobush]

Wait, are they saying 33 Kelvin is high temperature when it comes to super conductors?

[dagw]

Traditionally (or at least when I was at University ~20 years ago) anything above 30 Kelvin is considered a high temperature super conductor.

[tigershark]

Not really, I think that now superconductors that can be cooled down by just liquid nitrogen are considered high temperature. That’s 77k.

[tigershark]

I am not sure why they put the -240C figure in the article, but if their superconductor really needs that temperature then it’s not high temperature.

[TheSpiceIsLife]

We'd need to know how much energy is required to keep the system at that temperature.