On 30 April RWE integrated the world’s longest superconductor cable into Essen’s power grid, thereby putting it into field operation for the first time. About a year after ground-breaking for installation of the cable, which spans a distance of one kilometre and connects two substations in Essen’s city centre, this important field test for the future energy supply of inner cities is now underway. The technology here undergoing its first practical test has a capacity five times that of conventional cables, with almost zero losses.
This pilot project, which goes under the name AmpaCity, has been made possible by grants from the German Federal Economics Ministry for the Environment and Energy (BMWi). In fact, BMWi contributed €5.9 million to the €13.5 million invested in the project by RWE and its project partner the cable manufacturer Nexans, which designed a superconducting fault current limiter as well as the superconductor cable for the trial operation. AmpaCity is also supported by the Karlsruhe-based Institute for Technology (KIT), which is providing scientific assistance to the field trial.
The federal government justifies the research funding as a measure designed to meet the technological challenges posed by the energy transition for all players in the energy system. "With AmpaCity, RWE is again charting new technological territory. We were already able to gather first valuable experience when laying the cables and assembling the sophisticated technical components. Now we are keen to see how the field trial goes", commented Dr. Joachim Schneider, Technology Board Member of RWE Deutschland AG.
Christof Barklage, chairman of the board of directors at Nexans Germany said: "Following more than ten years of R&D in the field of superconductor technology, we can demonstrate, together with our partner RWE, via AmpaCity, that superconduction makes economic sense."
“For KIT, AmpaCity is an important milestone in the long-term research and development of superconducting grid components. The fundamental change the electricity grid will be going through as the integration of renewable energies continues is a motivation and challenge for us to continue contributing with innovative, superconducting solutions to a reliable, stable and efficient grid in the future, too," said Professor Joachim Knebel, head of division at Karlsruhe Institute for Technology.
High-temperature superconductivity and hence the transmission of electricity at minus 200 instead of minus 270 degrees Celsius goes back to the research work done by Dr Johannes Georg Bednorz, who won the physics Nobel prize for his work in 1987. At Essen, the 10 kV superconductor cable replaces a conventional 110 kV transmission line. This is also intended to reduce the number of transformer stations and to move them to the outskirts of cities, which would make valuable sites in city centres available again for other purposes.
