Superconductors: Cure for grid transmission woes?

One idea to get more solar and wind power into the grid is frozen cables buried underground.

American Superconductor, which makes superconductor wires, has developed a system to use direct current superconductor cables, which greatly reduce loss of energy during transmission. It's a way to beef up the U.S. power grid and bypass many contentious problems over siting overhead lines, according to the company.

Typically, plans to modernize the grid and meet growing demand for electricity involve adding bulk transmission lines. Also, more lines are needed to transport large amounts of solar and wind power from the west and Midwest to the load centers along the coasts. T. Boone Pickens last week said he is seeking new locations for a massive wind farm in Texas because the transmission lines are not available in panhandle region.

Underground direct current superconductor wires--a viable alternative to overhead transmission lines?

(Credit: American Superconductor)

But laying new transmission lines, in addition to be expensive, is meeting opposition from many quarters and brings up thorny debates over federal versus states rights in siting. In one case, a group of environmental advocacy groups is suing government agencies because the proposal to build transmissions lines through public lands is not well suited for transporting solar and wind power.

American Superconductor argues that superconductors get around many of those siting issues because cables can be placed underground on existing rights of way, company representative Jason Fredette said on Friday. Direct current superconductor cables are also far more efficient because there is minimal loss during transmission--only three percent. Losses today during transmission and distribution can be more than 10 percent of the energy generated, according to a 2007 Department of Energy study (click for PDF).

Superconductivity is possible when certain materials are lowered to very low temperatures, which makes the resistance drop off entirely. American Superconductor makes a ceramic wire that is cooled with liquid nitrogen circulated around the wires.

Researchers have been studying superconductive transmission lines for years and there are few installations of superconductor cables now in the U.S. for relatively short distances, a sign that utilities are more comfortable with using alternatives to aluminum or copper lines. But a long-haul direct current superconductor line is a big step from today's state of the art, Fredette said.

"The big barrier here, as with any new technology, is that electric utilities are very conservative...Now we're overcoming that obstacle with initial installations, which are relatively short runs but this superconductor pipeline is much grander in scale," he said.

In practice, the cables would be placed underground, as gas pipelines are, and have nitrogen cooling stations every seven or eight miles. Fredette said the technology is feasible but would likely need some sort of loan guarantee from U.S. government to test the system in the field.

[rwbrick1]

Question(s): Do the cooling stations run on electricity? How is the currect voltage obtained from the HVDC? How much of the 7% savings do the cooling stations eat?

[Seaspray0]

And more importantly, how reliable will the uptime be? If it's anything like the CERN supercollider, it will experience massive cost overruns and delays.

[BenFlavoredCandy]

I am guessing they would not talk about this technology if the energy used to sustain the temperature was greater than the improved transmission efficiency (depending on total transmission, of course), but I would be interested to see estimates on these values.

[screamapillar]

That and we must not forget that current transmission (overhead) technology also requires power to keep its levels up, so both have this issue (much like the radioactive waste from nuclear power debate that assumes incorrectly that coal power does not produce radioactive waste). But I'm with you, I'd like to see quantitative comparisons.

[Bakkster]

Does the cost of cooling and transporting the liquid nitrogen to keep the wires cooled, as well as the cost and efficiency of converting wind and solar power to DC (solar is DC already but may need to be increased/decreased in voltage, depending on the system) get offset by the increased efficiency of the lines?

Liquid Nitrogen is a relatively common coolant, but it still takes electricity to cool. Worst of all, if only a small amount of power is being transmit over the line, it still takes just as much energy to stay cooled. This means that if these lines are running to solar panels, they will COST energy overnight. If they're efficient enough and the solar plant is large enough, this could be more efficient than high-tension copper wires, but we need to make sure that's the case.

[contentcreator--2008]

Article says 3% loss. Since superconducting wires are zero loss in themselves, it seems reasonable to conclude that the 3% loss is the power required for cooling and distributing the liquid nitrogen.

[weaselander]

Well a 7% savings of the total electrical output from the US is enough to buy 260 billion litters of liquid nitrogen using the values I found online. So even if those numbers are off by a factor of 10 or 100, I think the savings will be worth it.

[contentcreator--2008]

The 3% is the power required to MAKE the liquid nitrogen --- it just takes a fancy refrigerator, that's what the stations every few miles are presumably for.

[ducttape36]

but it also depends on how much energy is being transmitted and how long the lines are. the longer the lines, the higher the cost. it wouldnt make much sense to transmit a low amount of electricity over a long line, but the reverse could offer big savings.

[freemarket--2008]

@ducttape36: First off, you wouldn't invest in transmission lines unless you had a lot of energy to transport. Second, the line losses for normal transmission lines increase with distance as well. Ideally the lines should go from the point of origin to the nearest large consumption point, then to the next and so on.

[pjcamp]

That's a ridiculous idea. The need for a highly insulated nitrogen conduit surrounding the wires, and cooling stations every few miles (which requires electricity, presumably from the grid, which in turn reduces efficiency) are in themselves prohibitive. But add to that the fact that high Tc superconductors are ceramic materials, and therefore very brittle, and therefore subject to breaking at the drop of a hat, and you have a recipe for an unstable power grid with random brownouts.

If you want to do something with superconductors, it makes far more sense to build large underground electromagnets out of them and use them like a battery -- solar and wind power generate electricity which is stored in circulation in the superconductor, and drawn out when the sun is down or the wind isn't blowing. That puts everything in one place which means less need for nitrogen and less need for cooling.

[martin1212]

Perhaps you should write to them and tell them that the cooling cost will be prohibitive. I'm sure they have not thought about that at all. </sarcasm>

[martin1212]

And on the brittleness issue, that has been resolved too if you would just do a few seconds of research:

http://www.newsweek.com/id/200068

"scientists and engineers at a handful of companies in Europe, the U.S. and Japan who have figured out how to turn brittle, fragile superconductors into flexible wires. "We basically found a way to bend the unbendable," says Greg Yurek, who left the MIT faculty in the late 1980s to found American Superconductor in Massachusetts."

[freemarket--2008]

I love it when Joe Blow puts on his engineer hat and tells us something can't work. As the saying goes 'Better to be silent and thought a fool...'

[corkyboyd]

"The big barrier here, as with any new technology, is that electric utilities are very conservative"

It's not that they are conservative, it's they have to be assured they can fulfill demand 100% of the time. There are still reliability questions with super conductivity. Also, while efficiency is important, overall cost is more important. Capital and operating costs can change the equation.

For instance solar is in theory free. Utilities in California were paying over 70 cents a kilowatt hour for solar because of capital costs. This is 5 times the average retail delivered cost of electricity in the state. They only buy it at these exorbitant prices because California makes them do it. And Californians end up paying the higher prices.

The high temperature superconductivity has been around for over 20 years, yet it hasn't caught on.

[dlevinsky]

Wow. American Superconductor was touting this nonsense more than 15 years ago. Looks like it has made zero (pun intended) progress. And, I see that the company keeps losing money and, in fact, has never reported a profit since going public in 1991.

But those are just details. I am sure one of these decades, they'll figure out how to make a real business out of what, until now, has been a monumentally bad pipe dream.

[cosuna]

dlevinsky:

Every new idea always sounds like nonsense when it starts. Remember "Plasma" hang on the wall TV's of the 80's (read Popular Science). It sounded stupid... why would I need a TV that's the form factor of a painting... well you need it if you want WideScreen...

Electric cars... with gas a 1 dollar a gallon (back in the 70's) it sounded far fetched, even in times of the embargo. When gas prices reached almost 3 dollars, things changed.

That's how technology works. Hope American Superconductor can withstand another 5 to 10 years to see their dreams come true.

[screamapillar]

Dare I add to cosuna's list:

*The Earth is round not flat
*The Earth revolves around the sun (not the universe revolving around us - the equivalent debate atm is darwinism)
*We are made out of cells (not just divine)
*Evolution (still debated despite the overwhelming evidence eg. fossil record, DNA similarities, redundancies in DNA)
*Natural selection (also still debated, some STILL even argue Lamark's perposterous theory of adaption/acquisition of traits which is why people don't understand things like needing to take the whole course of antibiotics, not just enough until you feel better...)
*Mental illness vs. demon possession (still debated in many circles)

People were executed (Gallileo for example) for making these claims/discoveries that we now take in our stride...

[carlhage]

It really comes down to cost. The first superconducting transmission line (search holbrook superconductor in Wikipedia) came on line about a year ago-- 600m at $60M, or $100,000/meter. If you are going through Manhattan, it could be worth that, but hard to justify in the plains of Texas. One theoretical paper estimated a 1000km line at $800M with losses at 0.1% including refrigeration power, but there is a big difference between $800/m and $100K/m. The proposed 150mi Sunrise Powerlink is estimated at $1700M, by comparison ($7K/m).

[Bill_I]

These superconducting promoters must be smoking small funny cigarettes.

[Daddio2009]

The regeneration stations yank nitrogen out of the atmosphere. The technology to do this generates its own power, using the FM principle.

[galeso]

Could you build me one?
I could use some of that free power.

[galeso]

This will suck all of the nitrogen out of the air, leaving nothing but CO2. We will all be killed so some corporation can make a few bucks. I bet they did not think of that or did they? </smoking_funny_cigarettes>

[GO ILLINI]

Leaving nothing buy CO2!!! (And O2 and Ar and Ne and CH4 and Xe and H2 and Kr and He)

CO2 is only .03% of our air with breathable O2 at 21% and Nitrogen at 78%. If it were even close to possible (they did it in SpaceBalls the movie!) to remove 78% of our atmosphere, there would be no need to worry about the rising(ish) amount of C02. at .03% it would be easy to get rid of right!?

[kurtpochert]

I would put the superconductor transmission of electric power akin to the present development of the battery for electric vehicles. Only now are the dream of flat panel TV's realized after many years of the CRT. It is the same way for electrical storage batteries and electrical transmission lines. Why don't we put cold fusion on the table as well? I would love to see a safe package of fusion technology that can be put into a car, and 100 to 200 thousand miles later just recycle the whole thing for a new car. The same technology could eliminate huge long distance transmission lines all together. Big dreams, lots of hard work, and time too, and it will happen.

[Holly Klug]

I wonder how they boot strap this when the power fails? Do they have diesel generators at each cooling station? Or a separate non-superconducting line? It could take as long as a nuke to get back on line (weeks).