Coordinated V2G scheduling of plug-in electric vehicles in hybrid renewable energy systems

The present work develops a coordinated scheduling scheme for plug-in electric vehicles incorporated in a hybrid renewable energy system that combines photovoltaic energy generation, wind energy generation, and battery energy storage. A mathematical and economic model that incorporates energy scheduling, cost analysis with considerations of the degradation of the battery system, and a technical network analysis is developed for optimization of power flow and improvement of the practical benefit of the vehicle-to-grid operations. A sequential two-step algorithm has been adopted in this study. At the first step, the operating schedule of the combined battery energy storage system and electric vehicle system is determined with consideration of the device-level constraints under tariff-driven operation mode. At the second step, the scheduled power of the electric vehicle is delivered to a nine-node test distribution network through an equivalent representation of the electric vehicle using voltage source converter models. The Newton–Raphson power flow method is used to calculate the network voltage deviation and the total power loss. In the simulation studies, two operating scenarios have been considered to simulate high and low levels of grid-supportive discharging by electric vehicles. The coordinated scenario increases the daily discharged energy from 671.64 to 1038.6 kW with a 127.86% increase. Moreover, better energy consumption performance and economics of the residential user energy network with coordinated electric vehicle scheduling has been shown.