Flywheel Energy Storage Systems Compared to Competing Technologies for Grid Load Mitigation in EV Fast-Charging Applications

The transition from fossil fuel-based transportation to clean, electric mobility has to be considered one of the crucial steps towards decarbonization. However, along with the strong projected increase of electric vehicles, a number of new challenges arise. Especially the continuously rising charge power in combination with an increasing supply by volatile sources result in high loads on the grid, which may cause instabilities and - in the worst case - even blackouts. Within this paper, the possibility of integrating a flywheel energy storage system (FESS) into a photovoltaic-assisted fast-charging station to stabilize the grid is discussed and compared to competing technologies. By introducing energy storage, even with only a low-voltage distribution grid at hand, high charge-power can be provided while at the same time stabilizing the grid. Superior cycle life of the flywheel energy storage, the ability to feed power back into the grid as well as easy transportability are further advantages of FESS for EV fast charging. Several use-cases ranging from the private home user to public transportation are evaluated based on analytical calculations. Characterization of FESS was performed based on real prototype measurements and field tests.