Economic comparison of electric vehicles performing unidirectional and bidirectional frequency control in Denmark with practical validation

The paper aims at investigating different methods, based on unidirectional charge and Vehicle-to-Grid (V2G), in order to evaluate and compare the potential economic revenue for an EV owner in providing frequency control in Denmark. User constraints are considered while evaluating the daily duration the EV is plugged into the network ready to support the system frequency. Performing unidirectional frequency control with Electric Vehicles (EVs) requires little hardware implementation in the household but has the limit that the service only can be performed until the battery is fully charged. Bidirectional V2G frequency control requires an external charger but also enables the EV to perform services at higher powers, during the entire period the EV is parked. The yearly revenue is in both cases calculated using some assumptions that are then verified in 2 experiments. Both EVs are discharged with the same amount of energy, such that their initial State of Charge (SOC) is set to the same level.