Evaluation of the flexibility provision behaviour of different charging strategies for electric vehicles

Electric vehicle charging offers great potential for providing flexibility in the electric power grid by acting as mobile energy storage and providing both uni- and bidirectional flexibility. So far, various simulation methods have been developed to estimate the flexibility potential, but these are often based on theoretical assumptions and refer to an optimal charging behaviour of EVs. This assumption, however, is not always valid. Considering real-world behaviour, which depends on the EV type is, therefore, essential for future simulation and evaluation of EV-flexibility provision. Within this work, issues such as the reliability of charging/discharging processes, response times, efficiency levels, minimum possible charging power, plausibility of the ISO 15118 parameters and different charging profiles are examined in detail. Different vehicle models are tested regarding their ability to provide flexibility, taking into account various charging and discharging scenarios. The results are then verified with external measurements. It could be shown that the behaviour of vehicles from different manufacturers differ in their inherent charging behaviour, which can be significant for reliability of flexibility provision, since the realization of predefined charging profiles is not always possible. Furthermore, the realization of predefined charging profiles is not always possible. The ISO 15118 partially transmits incorrect parameters. Hence, the provision of flexibility within a field-test faces several challenges, that has to be considered in the estimation and activation of flexibility potential.