Superconducting cable reliably supplies 10,000 households with electricity

November 12, 2014 by Monika Landgraf, Karlsruhe Institute of Technology
Superconducting cable reliably supplies 10,000 households with electricity
KIT’s fundamental research into superconducting materials and components as well as its feasibility studies contribute to the success of AmpaCity. Credit: KIT

180 days or 4300 hours – for this period, the AmpaCity superconducting cable in Essen, Germany, has been conducting power so far. On October 27, the project partners, inclusive of the Karlsruhe Institute of Technology, are taking positive stock. The superconductor transports five times more electricity than conventional copper cables with hardly any losses. Since its commissioning on April 30 this year, the cable of one kilometer in length has distributed about 20 million kilowatt hours, corresponding to the consumption of about 10,000 households in Essen.

"The AmpaCity project shows that it is possible to transfer fundamental research to application," Mathias Noe, Head of the Institute of Technical Physics of KIT and project partner of AmpaCity, says. "Research contributes to solving societal challenges, such as the transformation of the energy system in Germany. For this purpose, application-oriented fundamental research financed from federal funds takes place in close cooperation with innovative industrial development."

After 180 days of operation, the project partners now took a first positive stock. "So far, operation has taken place without any trouble. We have obtained valuable technical findings that helped us further optimize the superconductor system," said Dr. Joachim Schneider, Chief Technical Officer of RWE Deutschland. The project partners modified the system monitoring scheme for an optimal integration of the superconductor into the protection system of the Essen power grid. In addition, the cooling cycle of the cable was adapted to the special requirements of AmpaCity.

The AmpaCity flagship project that has meanwhile gained worldwide recognition is financed from funds of the Federal Ministry for Economic Affairs and Energy (BMWi). "The Energiewende needs courageous innovations for an efficient and secure design of tomorrow's energy system. That is why we deliberately selected this excellent project for funding under our energy research program," said Uwe Beckmeyer, Parliamentary Undersecretary of State with the Federal Minister for Economic Affairs and Energy, during his visit in Essen. The BMWi funded the project with EUR 5.9 million. An investment of EUR 13.5 million was made by the project partners. These are RWE as the grid operator, the cable manufacturer Nexans, and Karlsruhe Institute of Technology (KIT) that scientifically supports the field tests.

Prior to the AmpaCity project, KIT coordinated a detailed study relating to the technical feasibility and economic efficiency of the use of superconductors on the intra-urban medium-voltage level. Superconducting cables are the most reasonable option to reduce high-voltage cables in urban grids, to simplify the grid structure, and to dismantle resource- and area-consuming transformer stations. Copper medium-voltage cables can transmit high powers in cities at comparably low costs, but Ohmic losses are high. The preliminary study highlights the advantages associated with the use of 10,000-volt superconductors in the intra-urban distribution grid and the dismantling of high-voltage facilities. In the medium term, this would result in an enhanced efficiency, a leaner grid, and reduced operation and maintenance costs with a smaller consumption of areas in the city.

High-temperature superconductivity and power transport at minus 200 instead of minus 270°C is based on research conducted by Professor Alex Müller and Dr. Johannes Georg Bednorz, who were granted the Physics Nobel Prize in 1987 for their work. Thanks to the properties of the superconducting material, a special ceramic, and its cooling to minus 200°C, the cable is turned into an ideal electric conductor. In Essen, the 10,000-volt replaces a conventional 110,000-volt line.

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1 / 5 (4) Nov 12, 2014
Ultraconductors, polymer equivalents of room temperature superconductors, will provide transmission line cables in the future. See that heading on the Aesop Institute website.

These materials had 20 years of development before a decade long funding gap following the crash. Development is resuming with new capital.

Four SBIR contracts were successfully completed, including a Phase II with the USAF. All four Final Reports are available upon request.
4 / 5 (4) Nov 12, 2014
Another in a long list of projects that promote somebody or company but that do not compute for the real world. There is no superconductor that conducts at room temperature, none, nada. This superconductor is cooled in a vacuum tube to the temperature of liquid nitrogen or less. The heat leaking in through the vacuum tube has to be removed by an expensive pumping system, the longer the tube the more expensive the pumping system. It is physically impossible to build say 100 miles of this tube at a cost the consumer could afford. If they ever come up with room temperature superconductors than come back again. The previous poster on polymer ultraconductors is not reporting a real product, that idea is simply a hypothesis, nobody has actually produced one. All those SBIR contracts are contracts to study the idea, it is the same as saying lets study the idea the moon is made of green cheese. Without a green cheese actual moon, the study is worthless.
2 / 5 (4) Nov 12, 2014
So they have a more efficient wire that takes more energy to transmit than you would lose with resistance.

Then people wonder why societies are going bankrupt....
3 / 5 (2) Nov 12, 2014
the other tiny problem is the superconductor is not conducting AC current, they are sending DC current through the conductor which would mean a large converter at the consumers end which adds to the cost.
not rated yet Nov 12, 2014
Super conductors have their uses. For things where the volume is small, the current is large, the magnetic fields are useful with large currents they make a lot of sense, some MRI machines are an example and field coils for physics research. They are not much good for most other things. The military is interested as they would reduce the size and weight of rail guns and make electrical driven lasers much more efficient reducing the power plant size and the size of the launcher or laser. If they ever get to room temperature conductors you could make electrical driven rocket engines. In the civilian sector the cost would have to be near or the same as copper or aluminum to ever take hold.
Keyto Clearskies
5 / 5 (4) Nov 12, 2014
The above comment by the professional con artist and swindler Mark Goldes is a typical example of the thousands of false and fraudulent advertisements he has posted for his fraudulent so-called "Aesop Institute," which has been his instrument to swindle people with false and empty claims of make-believe "breakthroughs" for many years. Mark Goldes has no "astonishing new science," and no "prototypes" of anything - all he has is the same old fraudcraft he's been swindling people with for decades - first at MPI, and then at Chava Energy LLC and his so-called "Aesop Institute." He is nothing more than a fraud and a charlatan. He has deceived and swindled gullible people for decades with his endless empty claims of make-believe "breakthroughs," by persuading them to give him loans, which are never repaid. Learn the truth about Mark Goldes' fraudulent "Aesop Institute:"

5 / 5 (2) Nov 12, 2014
@Keyto Clearskies: All I can say is "Thank You". No sarcasm intended. You have probably saved countless numbers from investing in yet another 'too good to be true' scam.
3 / 5 (2) Nov 15, 2014
the other tiny problem is the superconductor is not conducting AC current, they are sending DC current through the conductor which would mean a large converter at the consumers end which adds to the cost.

That's not true. It's a three-phase AC cable. There are no converters.

DC is used only in long distance transmission cables because the AC would couple to ground capacitively and leak anyways, so the benefit of having zero resistance would be moot. Over short distances there isn't enough surface area for significant capacitive leakage.

It is physically impossible to build say 100 miles of this tube at a cost the consumer could afford.

That's why they're proposing to use it intra-city where it makes a parallel 110 kV distribution network unnecessary by transmitting 10 kV at a higher current. The 110 kV then would only have to reach the edges of the city, and that saves on the number of transforming stations and HV-cable corridors within the city.

not rated yet Nov 15, 2014
They did not mention the gas they use to cool the cable. Nitrogen boils at -196c is that the -200c that they are referencing? If not that means that they are using liquid helium which is in really short supply and not really practical for use on such a large scale.

I just answered my own question, a quick search shows that they use liquid nitrogen.
5 / 5 (1) Nov 15, 2014
I just answered my own question, a quick search shows that they use liquid nitrogen.

They only need a small amount of liquid that boils below -200 C to cool the nitrogen in a closed loop refridgeration unit.

The nitrogen itself doesn't boil - it's meant to remain a liquid throughout because having boiling nitrogen inside the cable would create bubbles and voids that would allow the superconductor to heat up and become resistive again.
not rated yet Nov 15, 2014
Hope they learn a lot with this, for another goooood use is on spacecraft, like plasma drives e.g. VASIMR or M2P2. Carry huge currents from nuclear reactors to magnetoelectrohydrodynamic electrical converters for ship power while thrusting. Another plus would be that in space, no need for huge cooling effort as long as the conductor is shaded and not in contact with warm things.
1 / 5 (1) Nov 15, 2014
The Chinese have superconducting second generation Shawyer drives that can launch a space shuttle on their own from earth to space, no staging needed. They move slow as have a max deltaV of about ,01g/sec^2. Deceleration is not simiilarly encumbered, so these craft can return at a controlled descent and could conceivably land on a rooftop if so desired. See and related sites. We Americans are working frantically on this. All probably going on in secret. Whoever gets the first hardware working will literally OWN space. Key are the alpha=2 or so compact high output nuclear reactors to run it. THAT would probably be Russian, sorry to say but their science has not been encumbered by the gridlock politics played by our tea party party luddites who obsess over subsidies to the rich at the expense of the people.
not rated yet Nov 16, 2014
Thanks for that info Eikka. I never thought of that.
5 / 5 (1) Nov 16, 2014
So Osiris1 what you are saying is that those damn people who hold individual freedom above governmental power are holding back progress and innovation.
not rated yet Nov 17, 2014
The heat leaking in through the vacuum tube has to be removed by an expensive pumping system


Then people wonder why societies are going bankrupt....

If it helps dismantling just one transformer station then that's a huge saving in space (urban realestate!), material and maintenance (not to mention safety with regard to solar flares or people simply messing with power infrastructure). For that kind of money you can pay the upkeep of a lot of these cables. In the end it will be a cost benefit analysis to show which system is economically more viable in the long run. It's good that they are conducting a field test under realistic conditions. And from what I read it's not a foregone conclusion either way.

Earthquake resistance is, I would think, still an issue.

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