World record current in a superconductor

CERN does it again! I just don't know what, but it sounds impressive to a non-tech net-wanderer:

home.web.cern.ch...

In the framework of the High-Luminosity LHC project, experts from the CERN Superconductors team recently obtained a world-record current of 20 kA at 24 K in an electrical transmission line consisting of two 20-metre long cables made of magnesium diboride (MgB2) superconductor. This result makes the technology a viable solution for long-distance power transportation.

"The test is an important step in the development of cold electrical power transmission systems based on the use of MgB2," says Amalia Ballarino, head of the Superconductors and Superconducting Devices section at CERN. "The cables and associated technologies were designed, developed and tested at CERN. The superconducting wire is the result of a long R&D effort that started in 2008 between CERN and the manufacturer, Columbus Superconductors in Genova, Italy.

MgB2 is something called Magnesium diboride. I still don't know what this story means but I know how to link /snoops and links from wikipedia/:

en.wikipedia.org...

Its superconductivity was discovered by the group of Akimitsu in 2001. Its critical temperature (Tc) of 39 K (−234 °C; −389 °F) is the highest amongst conventional superconductors. This material was first synthesized and its structure confirmed in 1953, but its superconducting properties were not discovered until 2001.

Though generally believed to be a conventional (phonon-mediated) superconductor, it is a rather unusual one. Its electronic structure is such that there exist two types of electrons at the Fermi level with widely differing behaviours, one of them (sigma-bonding) being much more strongly superconducting than the other (pi-bonding). This is at odds with usual theories of phonon-mediated superconductivity which assume that all electrons behave in the same manner. Theoretical understanding of the properties of MgB2 has almost been achieved with two energy gaps. In 2001 it was regarded as behaving more like a metallic than a cuprate superconductor.

Apparently Columbus Superconductors isn't following on the publicity right now, as it's not on their main page yet. But here's who they are:
www.columbussuperconductors.com...

Columbus Superconductors SpA is a world leader in cutting-edge magnesium diboride (MgB2) technology and the transformation of this superconducting material into long, versatile and highly reliable superconducting wires. The company is vertically integrated, from R&D to applications and from production to sales.

Columbus Superconductors was established in Genoa in 2003 following successful cooperation involving ASG Superconductors, CNR-INFM (the Italian National Research Council) and a group of researchers. The company’s staff were some of the first to develop long wire prototypes and in 2005 set the world record with the first 1.6 km MgB2 tape. This milestone event paved the way to industrial applications for MgB2-based wires and their large scale production.

reply to post by Aleister

I'm not sure about the viability of cold superconductors for power transmission.

Transmission losses vary by location but let's say the power station has to generate 1080 watts to deliver 1000 watts to your home, with 80 watts being lost as heat from the transmission lines, transformers, etc.

The advantage of using superconducting wires is that their resistance is so low that the power line losses are practically eliminated, though you would still need transformers which have some losses. Well this sound fantastic, so why aren't we already doing it? I don't have the exact figures but if it takes let's say, 150 extra watts to refrigerate the superconductors, the fact that you saved up to 80 watts in transmission losses has no net benefit, and you're 70 watts worse off than you were without the superconductors. In addition, you would have the capital expense and maintenance costs of the refrigeration systems, which would far exceed the maintenance costs of a simple wire.

I do recall reading about CERN's electric bill which was maybe a million dollars a month, a large part of which was to run their superconductors.

There are a couple of possible ways around this problem, like more efficient refrigeration. The best holy grail solution would be room temperature superconductors, which have been sought but not found. Those would allow you to get the savings of reduced transmission losses, without all the additional refrigeration costs.

reply to post by Arbitrageur


Thanks, and I'll reread your post and try to long-term memory maybe 10 percent of it. This new whatever-it-is seems to be more about the length of wire that can be used in transmitting the energy created by the superconductor, and they seem excited about it. lol, but seriously, transmission length must be important and may be a fore-runner to wider practical use (feeding energy to entire cities?) of the eventual finds in this field.

reply to post by Aleister



NP

reply to post by theyknowwhoyouare


Thanks, I'll put on my duh hat and contact a mod. Nice catch of a bad fumble.

reply to post by Arbitrageur


For high load cables, especially underground ones, cooling costs are typically 50% of the I^2R losses.

EasyPleaseMe
reply to post by Arbitrageur

 

For high load cables, especially underground ones, cooling costs are typically 50% of the I^2R losses.

Cooling to what temperature? Current technology doesn't cool power transmission lines to superconducting temperatures.

Cooling costs to cool to superconducting temperatures will be much greater, right?

Arbitrageur

EasyPleaseMe
reply to post by Arbitrageur

 

For high load cables, especially underground ones, cooling costs are typically 50% of the I^2R losses.

Cooling to what temperature? Current technology doesn't cool power transmission lines to superconducting temperatures.

Cooling costs to cool to superconducting temperatures will be much greater, right?

edit on 15-4-2014 by Arbitrageur because: clarification

Well, the heat flux from I^2 R losses would be practically zero, a totally different situation. You'd have to overcome losses from imperfect insulation, but you won't have an intrinsic heat flux to dissipate.

mbkennel
Well, the heat flux from I^2 R losses would be practically zero, a totally different situation. You'd have to overcome losses from imperfect insulation, but you won't have an intrinsic heat flux to dissipate.

That is correct, but to further emphasize the contrast, the cooling costs could be more than a million times the I^2 R losses, right? I'm not sure if the i^2 R losses can even be calculated.

I do think there would be some economy of scale in cooling conductors carrying relatively large current for relatively short distances, as in cities, which might make it economical in certain situations. However when transmitting more modest currents over much longer distances through the countryside, I'd be surprised if the economics of cooling such long stretches of wire to superconducting temperatures plus maintaining the cooling apparatus would work out favorably.

originally posted by: Arbitrageur
That is correct, but to further emphasize the contrast, the cooling costs could be more than a million times the I^2 R losses, right? I'm not sure if the i^2 R losses can even be calculated.

I do think there would be some economy of scale in cooling conductors carrying relatively large current for relatively short distances, as in cities, which might make it economical in certain situations. However when transmitting more modest currents over much longer distances through the countryside, I'd be surprised if the economics of cooling such long stretches of wire to superconducting temperatures plus maintaining the cooling apparatus would work out favorably.

Yes only the highest current conductors such as city feeds and grid interconnects are economical to replace with superconductors at the moment.

originally posted by: EasyPleaseMe

originally posted by: Arbitrageur
That is correct, but to further emphasize the contrast, the cooling costs could be more than a million times the I^2 R losses, right? I'm not sure if the i^2 R losses can even be calculated.

I do think there would be some economy of scale in cooling conductors carrying relatively large current for relatively short distances, as in cities, which might make it economical in certain situations. However when transmitting more modest currents over much longer distances through the countryside, I'd be surprised if the economics of cooling such long stretches of wire to superconducting temperatures plus maintaining the cooling apparatus would work out favorably.

Yes only the highest current conductors such as city feeds and grid interconnects are economical to replace with superconductors at the moment.

That's at the moment, but maybe this new experiment, coupled with technology yet to be developed from it and from others like it, will create that possibility.

-- aleister, charter member of the 'Saying Nothing And Making It Sound Half-Way Decent Club' of Europe, America, and the wilder parts of Canada

a reply to: Aleister

I don't think that it will be too long before we can make useful room temperature superconductors, especially since the discovery that superconductivity can be accomplished via a certain material and conductor topology rather than the usual certain material and low temperature route.