Optimal EV Charger Level Specification for Residential Buildings with Renewable Energy

Abstract

Electric Vehicles (EVs) have witnessed high interest lately due to different environmental, socio-political, and economic factors. The chargers of EVs are categorized into three levels; L1 and L2. These chargers have different power ratings and prices. On the other hand, many houses started to add distributed energy resources such as photovoltaic (PV) to their existing power service. This paper investigates the optimal level of an EV charger for a residential building with renewable energy. The optimization aims to reduce the energy cost during the lifetime of the EV battery. The optimization constraints include the EV state of charge, the charging/discharging power limits of the EV, the EV expected availability, the house service size, and the EV maximum number of cycles. The study also investigates the feasibility of conducting a power service upgrade while keeping a power reserve for future load uncertainty. The problem is formulated as a non-convex optimization problem utilizing the Gurobi solver. The optimization problem is solved for different scenarios presenting different loads, PV power, and EV availability scenarios. Case studies are conducted using household data in Los Angeles, CA. The studies evaluated the energy cost saving for different levels of the chargers in the case of various PV sizes and energy tariffs. This research is a collaboration result between three commonwealth campuses in Pennsylvania State University.