PowerKERS – Kinetic Energy Recovery System for Personal Cars


The goal of the research project is to provide the fundamental technology for a durable, powerful, and economically as well as ecologically appealing high power energy storage system. The project covers the development of possible bearing and security concepts as well as the electromechanical energy conversion of the mechanical flywheel storage system used as high power energy storage in the field of automotive applications.

Project Description

Figure 1: Multi-body dynamics simulation of the vehicle-interface of a flywheel energy storage system
Approximately 20% of the European Union’s carbon dioxide emissions originate from road traffic. About two thirds of these emissions originate from passenger cars. Due to the low overall efficiency of conventional cars (about 18% in the New European Driving Cycle) a significant reduction of the emissions can be achieved. Two different approaches are being considered: Hybridization of the vehicle has the potential to reveal an overall efficiency close to the optimal efficiency of the internal combustion engine leading to a reduction of emissions by up to 55%. On the other hand, electric vehicles can be used allowing emission free driving. However, currently available hybrid and electric vehicles are not competitive compared to conventional cars, primarily due to the deficiencies of the electrochemical storage devices used (battery, supercap). For example, 75 kg of lithium ion cells are required to provide the energy content stored in a single liter of diesel fuel. Moreover, even though intensive research has been performed it is not possible to build a battery system that fulfils the demands concerning power and energy density, efficiency, life span, and costs. A competitive electric vehicle can only be built when using two separate energy storage components, namely a high-energy and a high-power storage device. The optimal energy storage device is a battery optimized for maximum energy content while an electro-mechanical flywheel storage seems to be the most suitable choice for the high-power energy storage. In case of a hybrid vehicle only the high power device is needed since the internal combustion engine or fuel cell system provides the main part of the driving power. Flywheel systems are also favorable considering economic and ecological aspects since their production does not require any limited resources and the system can be recycled easily. Within the project, different concepts to implement flywheel storages will be developed with respect to their applicability in passenger cars. This comprises the investigation of technical requirements (power limit, energy density, lifetime) as well as efficiency of the energy storage and target cost. The project involves the following research topics:
  • Acquisition (simulation and measurement) of typical load profiles of the flywheel used as high-power energy storage inside vehicles of different technologies (hybrid vehicles, electric vehicles, vehicle concepts using batteries/fuel cells).
  • Design and optimization of the bearing as well as the electrical machine in order to fulfil the identified requirements.
  • Crashworthiness of flywheel storages and behavior in case of system malfunction.


  1. A. Buchroithner, A. Brandstätter und M. Recheis, “Determining loads of rolling element bearings in mobile flywheel energy storage systems”, IEEE Vehicular Technology Magazine, Volume: 12, Issue: 3, Seite 83 – 94, Print ISSN: 1556-6072, September 2017.
  2. M. Recheis, A. Buchroithner, I. Andrasec, T. Gallien, B. Schweighofer, M. Bader, H. Wegleiter, “Improving kinetic energy storage for vehicles through the combination of rolling element and active magnetic bearings”, 39th Annual Conference of the IEEE Industrial Electronics Society (IECON 2013), Wien, Österreich, November 2013.
Contact Person
Hannes Wegleiter
Univ.-Prof. Dipl.-Ing. Dr.techn.
+43 316 873 - 30512
+43 316 873 - 1030512
Project Data

Project Type: Joint Proposal

Program: FFG New Energies 2020 – 3rd Call

Duration: 3 years

Status: Finished

Workgroup: Energy Aware Measurement Systems

  • FH Joanneum GmbH
  • Institut für Maschinenelemente und Entwicklungsmethodik (TU Graz)
  • Virtual Vehicle GmbH
  • Technsiche Universität Wien