  A major challenge for power grids with a high share of renewable energy
systems (RES), such as island grids, is to provide frequency stability in the
face of renewable fluctuations. In this work we evaluate the ability of
electric vehicles (EV) to provide distributed primary control and to eliminate
frequency peaks. To do so we for the first time explicitly model the network
structure and incorporate non-Gaussian, strongly intermittent fluctuations
typical for RES.
  We show that EVs can completely eliminate frequency peaks. Using threshold
randomization we further demonstrate that demand synchronization effects and
battery stresses can be greatly reduced. In contrast, explicit frequency
averaging has a strong destabilizing effect, suggesting that the role of delays
in distributed control schemes requires further studies.
  Overall we find that distributed control outperforms central one. The results
are robust against a further increase in renewable power production and
fluctuations.
