Charging infrastructure for electric mobility using overhead lines
Expanding renewable energy sources in the mobility sector will play a key role in a successful energy transition. One particularly relevant aspect is finding ways to use existing grid structures efficiently, i.e. leveraging existing infrastructure as a lower-cost alternative to installing new systems. Part of this project is the development of a DC charging infrastructure (DC-LIS) for electric vehicle charging stations that will supply energy directly from the overhead lines that the trams use.
Duration: July 2020 until June 2023
Funded by: Federal Ministry for Economic Affairs and Climate Action
Project Participants: Institut für Vernetzte Energiesysteme Institut für Verkehrssystemtechnik SEN - System Entwicklung Nordhausen GmbH Stadtwerke Nordhausen – Holding für Versorgung und Verkehr GmbH Fachgebiet Stadt- und Regionalökonomie an der Fakultät Architektur und Stadtplanung der FH Erfurt (Evaluation & Transfer) Institut Stadt I Mobilität I Energie (ISME)
Project Manager at the Institute of Networked Energy Systems: Gerrit Bremer, Thomas Esch
Project Description: Expanding renewable energy sources in the mobility sector will play a key role in a successful energy transition. One particularly relevant aspect is finding ways to use existing grid structures efficiently, i.e. leveraging existing infrastructure as a lower-cost alternative to installing new systems.
City-centre charging stations for electric vehicles are usually connected to the public alternating current (AC) grid. For a fast-charging station, this alternating current is first converted into the direct current (DC) needed for the process. The DC-LEO project aims to tap into the power capacity of overhead tram lines, which already carry direct current. However, they normally experience severe fluctuations in operating voltage. As part of the project, a DC charging infrastructure (DC-LIS) is to be set up to allow the energy supply to come directly from the overhead lines. The development of this infrastructure will first be validated in a laboratory environment with the aid of a trial charging station before being tested in real-world conditions at the depot in Nordhausen, and then ultimately integrated into public spaces around the city.
The work of the scientists at the Institute of Networked Energy Systems can be roughly categorised in two main areas. On the one hand, they are conducting site and environment analyses along with their own field measurements in order to create a digital map of Nordhausen’s network of overhead lines. They are also analysing existing Vehicle-to-X (V2X) communication structures and standards for charging infrastructure. A demand profile for the future charging infrastructure will then be drawn up based on the simulation results and needs analyses. In their second main area of activity, the data obtained and the simulation models are being transferred to the Institute’s network emulation laboratory (NESTEC). There, the various voltage profiles can be replicated and the hardware developed and tested in a secured laboratory environment without affecting the city’s grid. The different V2X communication structures can also be reproduced and tried out there. The knowledge gained in the subsequent test phase at the Nordhausen depot can be incorporated directly into the ongoing development of the network emulation.
It will then be possible to present the project findings within a scientific framework, encouraging intensive dialogue and making a key contribution to the energy transition through the interdisciplinary advancement of the technology.
Further information on the Research Project DC-LEO: