Battery Buffered EV Fast Chargers on Bornholm: Charging Patterns and Grid Integration

The widespread adoption of electric vehicles (EVs) is a vital step in the reduction of emissions within the transport sector. However, the development of public fast charging infrastructure and the proper modeling of EV charging behaviours is required to enable this adoption. This paper presents charging data and patterns observed at a battery buffered fast charging DC microgrid on the Danish island of Bornholm. The charging sessions observed at this single site tend to be shorter with lower total energy transfer compared to studies with a wider scope. An atypical uptake of charges with higher than average energy transfer late in the evening is also observed. A simulation based study using this charging data to examine the effectiveness of the battery buffers at facilitating EV fast charging at reduced grid capacities is then presented. This study shows that the Bornholm DC microgrid would have been able to supply all observed EV charging at a reduced grid capacity of 11kW, enabling such a system to provide EV fast charging at a much wider range of locations.