Optimal sizing and energy management strategy for EV workplace charging station considering PV and flywheel energy storage system

In electric vehicles (EV) charging systems, energy storage systems (ESS) are commonly integrated to supplement PV power and store excess energy for later use during low generation and on-peak periods to mitigate utility grid congestion. Batteries and supercapacitors are the most popular technologies used in ESS. High-speed flywheels are an emerging technology with properties that could make them competitive with more mature battery and supercapacitor technologies in some EV charging applications. In this article, an EV workplace charging station with a flywheel and PV hybrid system (FL-PVHS) is examined. To make the cost of integrating these distributed energy sources more appealing and cost effective, the optimal sizing and operational cost of the hybrid system are investigated. To achieve realistic results, a detailed components cost is evaluated, taking into account the initial investment cost, annual maintenance price, degradation cost, replacement cost, and residual value. A flywheel power rating scheduling is performed to provide the best way to use its charging and discharging during the day while retaining a sufficient state of charge to ensure next day continuity of service. A comparative study is carried out with various models of EV charging station feeding, including a Li-ion battery and PV hybrid system (Bat-PVHS) and a basic system that feeds the station from the power grid only (GO). This comparison study is conducted for hot, warm, and cold climate zones. An exhaustive technical and economical study on the system lifetime is conducted to demonstrate the cost effectiveness and efficiency of the proposed system in comparison to existing systems using economic engineering principles as well as self sufficiency (SS) and self consumption (SC) as load matching indicators. The obtained results could help determining the viability of deploying such a system in light of the region's meteorological circumstances.

Automated summary

In electric vehicle charging systems, energy storage systems (ESS) are commonly used to supplement solar power and store excess energy. This article explores a hybrid system with a flywheel and PV for an EV workplace charging station. The study investigates the optimal sizing and operational cost of the hybrid system to make it more cost-effective. Comparative studies are carried out for different charging station models in different climate zones to determine the viability and cost-effectiveness of the proposed system.