AmpaCity superconductor

innogy lighthouse project on smart grids

Das längste Supraleiterkabel der Welt: AmpaCity bringt eine technologische Weltpremiere nach Essen. (Quelle: RWE)

Freezing cold energy transmission

innogy brought a world premiere to Essen in 2014: In the AmpaCity project, two transformer stations in the city centre of Essen were connected with a superconducting cable system for the first time.

Since then, the underground cable has been transmitting electricity over a distance of one kilometer almost completely without losses. This is made possible by the use of superconducting ceramic wires and extremely cold temperatures instead of copper or aluminum cables. The so-called high-temperature superconducting cable (HTS cable) is cooled down to around minus 200° Celsius. At this temperature, the resistance of the ceramic conductor drops to almost zero – the electricity can flow almost completely without losses.

AmpaCity in pictures

A giant cable reel: laying the superconductor cable
Installation and laying of the cable

AmpaCity in pictures

nitrogen tank at the substation Herkules
nitrogen tank at the substation Herkules

AmpaCity in pictures

The superconductor cable ends in a U-bend in the substation.
The superconductor cable ends in a U-bend in the substation.

Space-saving, environmentally friendly and resource-friendly

HTS cables are regarded as future-oriented technology for space-saving and energy-efficient power transport. They are environmentally and resource-friendly, as metals such as copper or aluminium, which are available in limited quantities and expensive, are hardly needed. 

In cities, HTS cables promise special advantages: they can replace up to five conventional cables. In addition, fewer transformer substations are required, because superconductors can transmit even large electricity volumes at a lower voltage. In this way valuable spaces in the city are freed up for other uses.

Since its commissioning, the cable between the two substations Herkules and Dellbrügge has been integrated into day-to-day grid operation and supplies the city centre of Essen - without any power disturbances so far. The field test shows that the technology is efficient, economical and integrable.

Timeline diagram depicting milestones of the AmpaCity project (Source: RWE)

innogy implemented AmpaCity together with Nexans, one of the leading European cable manufacturers, and the Karlsruhe Institute of Technology (KIT). The research project was funded by the Federal Ministry of Economic Affairs and Technology.

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