Model regions and regional pilot projects

Superconductors for network expansion – transporting high capacities in an energy-efficient manner

Case Study AmpaCity Project, Essen
By 2050, 80% of electricity should come from renewable sources. However, in 2011 alone, about 500 GWh of wind power was lost due to network congestion. Now an extensive network expansion with a focus on medium voltage grids is called for. Superconductor cable systems can provide high capacities for energy-efficient, space-saving and low-emission power transmission. The AmpaCity project in Essen, Germany, shows the way with the longest superconductor medium-voltage cable to date.

construction of a superconductor cable

Planned route of superconductor cable

The world’s longest superconductor cable is installed in Essen in 2013. A current limiter, which is also based on superconductor materials, protects the cable against excessive currents e.g. in case of a short circuit in the grid. The combination of both technologies by their manufacturer Nexans is exemplary for the modernisation of electricity networks in major cities throughout the world.

The system solution provides cables with a very high current-carrying capacity (or “ampacity”) which enables power distribution with minimal line losses even at a medium-voltage level of 10 kV. 110 kV high-voltage lines and substations in city centres, which until now have been necessary for an efficient electricity supply, could largely be dispensable in the future. According to a study assigned by network operator RWE, four city centre substations in Essen could be closed down as a result of a network modernisation with superconductor technology.

At the same time, authorization processes and routing problems as well as extensive construction work in city centre areas can be mitigated: superconductor cables which are protected by a current limiter do not call for an overload conductor and are therefore extremely compact. The system that is installed in Essen can transport the same amount of electricity as five conventional medium-voltage cables. In addition, it does not generate electromagnetic fields or heat emissions and the path for routing can be smaller than with conventional medium- or high-voltage cables. As a consequence, existing routes can be used for the network expansion, and high-ampacity superconductor cables can even be operated in close proximity to data lines and other utility systems without causing any problems.

To start with, AmpaCity provides a model for the urban network development. In the medium term, superconductor medium-voltage technology will also play an important role in the upgrading of wide-area distribution networks and in connecting renewable energy sources.

contact details/company:
Nexans Deutschland GmbH
Kabelkamp 20
30179 Hannover

contact person:
Dr. Joachim Bock
Director Sales and Market Development HTS Systems Nexans