Efficient Management of Electric Vehicle Charging Stations: Balancing user preferences and grid demands with energy storage systems and renewable energy

Renewable energy sources (RESs), combined with energy storage systems (ESSs), are increasingly used in electric vehicle charging stations (EVCSs) due to their economic and environmental advantages. To highlight its advantages, extensive studies have been conducted on the techno-economic and environmental impacts of integrating RESs and ESSs into EVCSs. However, important aspects such as load management capabilities and the operational efficiency of these systems in EVCSs have received comparatively little attention. This paper addresses this gap by investigating the load management and operational efficiency of combining RESs and ESSs with ultra-fast direct current chargers (UFCs) in an EVCS. It conducts a hypothetical case study on a commercial Evie network (charging company) charging station having 4 ultra-fast charging ports, in Australia, to investigate three load management strategies: 1) user-preferred, 2) grid-preferred, and 3) renewable energy resources - battery energy storage integrated systems (ReBIS). The study investigates the load management and operational effectiveness of these strategies in combination with techno-economic analysis. It highlights that the ReBIS effectively reduces grid peak demand, maximizes charging sessions, alleviates grid strains, and balances both user and grid charging preferences. Simulation results indicate that ReBIS with UFCs lowers energy costs by 40 %, supports 99.4 % of user-preferred charging sessions, and cuts carbon emissions by 63.2 % and 65.2 % compared to user-preferred and grid-preferred modes, respectively. The results validate ReBIS with UFCs as the optimal load management strategy for EVs, balancing charging demand with grid stability.