Essen, 27 October 2014, RWE Deutschland AGThis pressinformation is more than two years old

World’s longest superconductor cable yields first new technological knowledge

  • RWE gives 180-day interim report for AmpaCity in Essen

  • Ministry-sponsored flagship project beats expectations

  • Superconductor has supplied about 10,000 households since commissioning

Essen’s superconductor has now been live for 4,300 hours. Today, Monday 27 October, RWE and its project partners gave a positive interim report on AmpaCity’s first 180 days at work. The world’s longest superconductor has amply fulfilled expectations, transmitting five times as much electricity as a conventional copper cable. As an added plus, dissipation is near-zero. Since commissioning the 1 kilometre-long cable on 30 April this year, RWE has used it to deliver around 20 million kilowatt-hours, equivalent to supplying around 10,000 Essen households with electricity.

Funding from the German Federal Ministry for Economics and Energy enabled the flagship project to go ahead. Since then, the eyes of the world have been on AmpaCity. “The energy transition calls for bold innovation. We need to design an efficient and secure system to meet tomorrow’s energy needs. So we had no hesitation in choosing this excellent project for sponsorship under our energy research programme,” explained Uwe Beckmeyer, Parliamentary State Secretary to the Federal Minister of Economics and Energy, on his visit to Essen.
Thus the Ministry has contributed EUR 5.9 million of the project’s total EUR 13.5 million costs, co-investing with RWE and its partners Nexans and the Karlsruhe Institute of Technology (KIT). For the field trial, cable manufacturer Nexans designed a superconducting short-circuit current limiter, as well as the superconductor itself, while KIT lent scientific support.

The superconductor transmits current at minus 200 degrees Celsius rather than minus 270. This “high” temperature is the fruit of research by Professor Alex Müller and Dr. Johannes Georg Bednorz, which won them the Nobel Prize for Physics in 1987. The properties of the superconductor’s special ceramic material, coupled with cooling to minus 200, make the cable an ideal electric conductor. In Essen, the 10,000-volt superconductor cable replaces a conventional 110,000-volt power line. This technology makes it possible to reduce the number of substations and shift them to the outskirts, releasing valuable inner-city land.

After 180 days of operation, the project partners have now released their first summary. “Operations have so far proceeded smoothly. We have gained valuable knowledge of this technology, which has helped us improve the whole superconductor system further,” reported Dr. Joachim Schneider, Technical Director at RWE Deutschland. The project partners have made some changes to system monitoring, to ensure the best possible integration of the superconductor into the Essen grid protection system. They have also adapted the cable cooling circuit to AmpaCity’s special requirements.

The new technical knowledge gained from the project has elicited keen interest, at home and abroad. Delegations from China, France, Ghana, Japan and the USA have already visited Essen to find out more about the technology on location.


RWE Deutschland AG
Sebastian Ackermann
Communications Officer
T 0201 12-23802
M 0172 2028979

About the Project Partners

Federal Ministry of Economics and Energy
The core policy aims of the Federal Ministry of Economics and Energy are to create reliable outline conditions for Germany as an economic centre, keep the country competitive and maintain high employment levels. The Ministry’s programme “Research for an Environmentally-Friendly, Reliable and Affordable Energy Supply” backs R&D into applications of modern energy technology with an annual funding of around EUR 406 million. The resultant innovations are paving the way for the design of the energy system of the future, and thus contributing to the goals of the energy transition.

RWE Deutschland AG
Headquartered in Essen, RWE Deutschland AG is responsible for the German activities of the RWE Group in the business areas Grid, Retail and Energy Efficiency. The company also manages RWE’s regional companies in Germany. RWE Deutschland AG has legally independent subsidiaries for retail, distribution system operation, metering and the marketing of technical services. Other subsidiaries hold responsibility for activities related to energy efficiency, including electromobility and gas storage. RWE Deutschland AG holds participating interests in around 70 regional and municipal utilities and employs a workforce of about 19,000.

Nexans Deutschland GmbH
Nexans Germany is one of Europe’s leading cable manufacturers. The company offers a broad portfolio of high-performance cables, systems and components for telecommunications and the energy sector. Other products are superconductive materials and components, Cryoflex transfer systems and specialist machinery for the cabling industry. The workforce in manufacturing, in Germany and abroad, currently numbers around 9080 people, and turnover for 2013 stood at approx. EUR 906 million. As a full member of Nexans Group, Nexans Deutschland GmbH is ideally placed to tap synergies groupwide, which it does in projects around the globe, research, development, knowledge transfer and other areas. For further information please visit

Karlsruhe Institute of Technology
The Karlsruhe Institute of Technology (KIT) is one of Europe’s leading energy research institutions. KIT supports the energy transition and the changeover of Germany’s energy system through its activities in research, education and innovation. KIT is a public corporation under the law of Baden-Württemberg. It fulfils a twofold mission as a university and national research centre, and is a member of the Helmholtz Association. With around 9000 employees, of whom just under 6000 work in science and teaching, and a student body numbering 24,000, KIT is one of Europe’s largest educational and research institutions.

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