Hybrid energy storage to increase grid flexibility when charging an EV fleet

This paper investigates storage requirements for a grid connected microgrid with PV generation and EV chargers. The aim is to limit the power exchange of the microgrid with the connected main grid. The used power imbalance profiles are constructed using artificially generated EV charging profiles and a PV power production profile. To investigate the storage requirements for this imbalance profile both for hybrid storage and for a single storage device, this imbalance profile is split into multiple sub-profiles. The achieved results show that the required grid connection can be reduced by between 76% and 85% by adding one or more storage device. Additionally, insight is gained into what type of storage devices in a Hybrid Energy Storage System are required with respect to the power, energy and ramp rate of the imbalance profile.