Research project ROLLEN

Rolling charging stations to relieve the grid



In order to utilise surplus energy from renewable sources such as sun and wind, it must be stored or distributed. The ROLLEN project (funded by the German Federal Ministry for Economic Affairs and Climate Action) is researching one distribution option using electric vehicles. Equipped with regenerative charging technology, these vehicles are designed to take surplus energy from the grid – i.e. store it – and distribute it variably in terms of time and space.

Reasearch project ROLLEN



September 2020 to August 2023

Funded by

Federal Ministry for Economic Affairs and Climate Action

Project participants

  • Institut of Networked Energy Systems
  • Honda R&D
  • ubitricity
  • Fraunhofer Institut IFAM

The prospects for using electric vehicles as rolling energy storage systems and charging stations is being investigated by the Institute of Networked Energy Systems in the project ROLLEN. ROLLEN grew out of the already concluded research project “Drahtlos (English: Wireless), which researched bidirectional, inductive energy transmission between an electric car and a home electricity supply.

The goal of the research project ROLLEN is variable distribution of excess energy from renewable sources in space and time by means of electric vehicles with inductive charging systems capable of feeding back into the grid. Whenever the vehicles are standing still, they connect inductively to the local power grid to act as quasi-stationary energy storage systems. When the vehicle departs, it transports the energy to another location, where it can be used at a different time. The time shifting of the available energy by an electric car at a fixed location was already investigated in the project “Drahtlos”.

Inductive energy transmission is very user-friendly and also maximises the time the vehicle spends connected to the energy source. This method is being tested with the help of prototype electric vehicles equipped with inductive charging technology and an automated energy billing system. The advantages of this energy storage and energy transport system include use of the vehicles even when not driving and avoidance of passing the electricity through the public grid. The feed-in and extraction of the energy are restricted to local grids, and the energy can be made directly available to the consumers.

The researchers of the Institute of Networked Energy Systems primarily investigate the effects of energy transport on power grids. To do this, they conduct simulations of the changing network load and investigate these at laboratory scale. They also provide assistance with evaluations of user acceptance.


Flexibilities and Ancillary Services

Research Group
Institute of Networked Energy Systems
Carl-von-Ossietzky-Str. 15, 26129 Oldenburg