A Superconducting Power Grid

[npts2020]

Any engineer worth their salt knows that a large percentage of generated electricity is lost during transmission. This fact along with the discovery of superconducting materials has inspired people to begin work on a superconducting power grid. While I am aware that this is not technologically feasible at the moment, superconductivity research is progressing rapidly and a new grid seems to me something worth planning to upgrade toward soon. My question is what kind of space considerations must be given for such a grid? Would it be possible to safely run it on current utility rights-of-way with no extra buffer zone? Is anyone in this forum involved in superconductor research of any kind?

[big314mp]

There was a scientific american article, maybe about a year ago, that suggested superconducting wires, run inside liquid hydrogen pipes. The idea was to jump start the hydrogen economy, as well as the superconducting grid, all in one fell swoop. The hydrogen provided the cryogenic cooling for the superconductor, and the whole assembly would fit on current utility company property.

[Sisyphus]

There was a scientific american article, maybe about a year ago, that suggested superconducting wires, run inside liquid hydrogen pipes. The idea was to jump start the hydrogen economy, as well as the superconducting grid, all in one fell swoop. The hydrogen provided the cryogenic cooling for the superconductor, and the whole assembly would fit on current utility company property.

 

How would that jump start the hydrogen economy? Hydrogen doesn't have to be run through pipes, it can be manufactured anywhere at any scale, with just electricity and water.

[big314mp]

The idea was that excess power (such as at night) from power plants could be used to generate hydrogen, and that this hydrogen could be used as an alternative source of energy at various distributed locations.

 

The idea was to have a few, large centers of hydrogen production, rather than many small ones. That way you minimize the number of energy "transitions" (i.e. heat -> electricity (through grid) -> H2, vs heat -> H2 or heat -> electricity (on site) -> H2).

 

The article mentions using nuclear power to directly crack water using heat, a process not well suited to local production.

 

Or you could just read the article, instead of listening to me mangle it

 

http://www.sciam.com/article.cfm?id=a-power-grid-for-the-hydr-2006-07

[insane_alien]

Aren't they already testing a liquid nitrogen cooled superconducting grid somewhere in new york? its a small one IIRC.

 

another easier option is to do away with the grid entirely and have localised power generation

[Klaynos]

I see a few problems...

 

Cost....

Energy requirements to cool the hydrogen...

The danger of hydrogen...

 

I'm yet to read ther article mind....

[I_Pwn_Crackpots]

What would we do in the event of a leak? How often would you have to replace the coolant under this system?

[npts2020]

If the technology was perfected right now, the cost would likely still be prohibitive. What I am interested in is building an automated national transit system, with part of the construction being a new power grid (see my blog npts2020.blogspot.com). The real question is how would you plan for retrofitting superconducting grid? I have little concept of how big or heavy the transmission lines (pipes) would have to be even after reading about it.

[big314mp]

What would we do in the event of a leak? How often would you have to replace the coolant under this system?

 

The premise of their idea was that the coolant would be liquid hydrogen, and would thus be used by people as a fuel. Therefore there is no "replacing" the coolant, as it is being cycled through the pipes to consumers.

 

Leaks would be quite a bit more problematic, however.

[swansont]

I'd like to see a comparison between the energy loss from transmission and the energy it would take to make and maintain the liquid helium/hydrogen for the superconductors. Along with a risk assessment for the inevitable failure of one part of the grid.

[bascule]

Surrounding a power transmission line which would carry a substantial amount of energy with something that's potentially explosive sounds like a bad idea and a great way to bring about a new class of massive grid failures: "an explosion occurred at a superconducting transmission line today"

 

I find that ironic as the sciam article opens with a story about a grid failure...

[CaptainPanic]

At the terribly low temperatures, although very serious, I would not consider a leak the main problem.

 

It all goes up in a big mushroom cloud if the insulation breaks off. Heat up the hydrogen until its vapor pressure becomes higher than the breaking pressure of the pipes, and you'll see a very interesting version of the BLEVE (Boiling liquid expanding vapor explosion). The vapor might then produce a secondary explosion when the hydrogen combusts. FYI, the boiling point of hydrogen is 20.28 K (at 1 bar), but at 30 K it is already 10 bars.

 

But my main concern about the whole idea is this:

Now we lose energy in the transmission of electricity.

In this new plan B, we'd have to cool some hydrogen. Now, unless you make one giant machine capable of cooling to minus-a-lot along the entire length of the grid (probably consuming part of the electricity flowing through it!), you end up pumping around really cold hydrogen. It's rumored that hydrogen might have superfluidity, but the experiment (afaik) was only done at very very small scale. My point is that creating a superconducting grid might end up consuming as much energy as a conventional grid... superconductors might have zero electrical resistance, but the super-insulation is not yet invented, and superfluids were not yet produced on a bulk scale so it's not sure that they show superfluidity at such scale.

 

I wish I knew a bit more about the cooling techniques for liquid hydrogen so I would be able to compare its energy consumption to the "waste" in conventional grids.

 

But answering the question, I think that IF it works, it would require less space than the current grid, although I would consider to build it lower to the ground (like oil and gas pipes), which might interfere with existing infrastructure.

[npts2020]

Aside from the problems of scale, cost, and safety, which may or may not be overcome in time, it seems like the real question is how much thickness of insulation would be required to maintain a supercooled fluid. Steam at 1000F will have a foot or more of insulation around the pipes, requiring at least 2 feet of space just for the insulation. However, the temperature differential between superconductor operation and ambient earth temperature is less than ambient and the above steam temp. Still it seems like the insulation alone will require more space than current lines (aside from the towers). I just am wondering how much more or if I am totally wrong about it?

[Klaynos]

I'd like to see a comparison between the energy loss from transmission and the energy it would take to make and maintain the liquid helium/hydrogen for the superconductors.

 

Agreed...

 

Also can anyone say "terrorist target"?

[bascule]

Given the LHC's recent failures and the need for prolonged cooling periods, I wonder: if such a line were installed, a problem detected, and the line brought safely down and repaired, how long before it could be brought online again? Days? Weeks? Months? It sounds like this system will operate far above absolute zero unlike LHC, but even so... were we dependent on it, it sounds like downtime could be severe.

[big314mp]

I figured the LHC would be down for a long time due to the need to ensure that the components all cool evenly. Dumping in liquid He would probably break it.

 

However if it is just a pipe, I figure it wouldn't be that delicate of a structure, and you could cool it quite quickly.

[swansont]

Given the LHC's recent failures and the need for prolonged cooling periods, I wonder: if such a line were installed, a problem detected, and the line brought safely down and repaired, how long before it could be brought online again? Days? Weeks? Months? It sounds like this system will operate far above absolute zero unlike LHC, but even so... were we dependent on it, it sounds like downtime could be severe.

 

Which is the motivation behind asking for a risk assessment.

 

The conundrum of building a robust system is that unless you could make the components redundant, you would need a whole bunch of spare capacity to accommodate a failure of that component.

[CaptainPanic]

Agreed...

 

Also can anyone say "terrorist target"?

 

That's about the worst argument possible against new developments. but obviously it should be included in the risk assessment. I think you'll find that a bomb attack on this hydrogen-filled superconductive grid will be the same as any leak with an ignition source present. Estimating the chance of it happening is the real tricky part (and it's where many people freak out nowadays, and lose their ability to look at things objectively).

[Klaynos]

That's about the worst argument possible against new developments.

 

I agree, but it's what the public will think, which is also an important aspect when trying to introduce something that will be astronomically expensive... Just think how much the black-hole idea about the LHC has got publicity...

[CaptainPanic]

I agree, but it's what the public will think, which is also an important aspect when trying to introduce something that will be astronomically expensive... Just think how much the black-hole idea about the LHC has got publicity...

 

Yeah, actually, now that I give it a little more thought... science often suffers from marketing problems. Scientists are often too honest.

 

But this can be easily overcome. Everyone with gas heating has a potential bomb in their homes. Nobody cares. Just a matter of the public getting used to the dangers, and decent marketing when something new is introduced.

 

I love the example of bad science-marketing of the LHC in the question: "Can the LHC create a black hole that can eat the earth"? - Scientists then give it a lot of thought, and are 99.999999999999999% certain that it will not happen, but 100% certain doesn't exist... so they answer the question with "probably not", which is then interpreted by the public as "the scientists think it might go right, but they're not certain at all".)

 

Just keep repeating the good stuff, and brilliant safety records. Airplanes are another great example where a large portion of the public totally ignores possible dangers. Of course, the safety record of airplanes is quite impressive nowadays, and liquid hydrogen superconductors still have a lot to prove.