Estimation of the Battery Degradation Effects on the EV Operating Cost during Charging/Discharging and Providing Reactive Power Service

Dynamic environment of the power system can be better controlled by the smart usage of electric vehicles (EVs). EVs with their diverse capabilities can create opportunities for Distribution System Operator (DSO) to improve the efficiency, economics, and sustainability of power delivery system. For instance, reactive power support can be provided by EVs quickly, when needed by the DSO. This type of ancillary service is becoming a necessity, due to higher power demands and continuous change in supply-demand environment. On the other hand, high battery price discourages consumers to purchase EVs. Therefor, creating ways to reduce the overall battery cost by generating revenue through participation in the power market, could be a win-win situation for both, EV owner and the DSO. Revenue generation for EVs could be achieved by supplying active and/or reactive power. In this paper, we present a model of EV operating as a reactive power service provider, considering the battery degradation, as a function of active power flow. The developed model includes charger technical constraints. Simulation results show optimal operating cost estimation, taking into consideration the effect of the battery degradation on charging, discharging and reactive power service of the EV under different scenarios. Results indicate significant change in active power charging and discharging patterns when the battery degradation cost is included. Revenue generating potential of providing reactive power service by EVs could be an encouraging fact for EVs to participate in reactive power market.