Grid Integration of Large-Scale Electric Vehicles: Enabling Support Through Power Storage

Abstract

This chapter presents the grid assistance opportunities through charging and discharging of electric vehicles (EV) and explores the technical and operational challenges in integrating the electric vehicle storage, a movable and changeable of its kind, with the power system. The initial step discusses the development of charging load curves of EVs based on mobility attributes and charging protocols. Researchers have also proposed the vehicle-to-grid (V2G) mode of operation of EVs in which a proportion of energy stored in the battery can be injected back into the grid at the peaking periods. Based on this, the second step discusses the evolution of V2G energy profiles with various discharge power levels for a defined mobility pattern. The heterogeneity in the vehicles as well as in the mobility behavior can further be incorporated to determine the grid-to-vehicle (G2V) and V2G power capabilities of the aggregation at different moments under varying penetrations of the electric vehicles.

The coordinated grid connection of EV aggregation can also be employed to provide short-term ancillary services like regulation, thereby increasing the power system reliability and side-by-side forming a revenue stream for the grid-connected vehicles for the contracts made in the competitive services market. Through coordinated charging and discharging of EVs, the controllability of the battery storage can also be utilized to achieve the control over the peak shaving, valley filling, and load leveling functions of the system operator. Finally, this chapter discusses the possible configuration of EV and electric power utility interfacing to manage the centrally dispatched EV aggregation, comprising system operator, vehicle aggregator, power supply equipment, and vehicle owner as the key participants.