## 1 Introduction  
The global transition toward sustainable transportation and clean energy systems has positioned battery energy storage systems (BESSs) as critical components in the evolution of modern power grids [1]. Within this context, electric vehicles (EVs) are increasingly recognized for their dual potential--particularly given that they remain parked for significant portions of each day--to store excess electricity generated by renewable sources and provide power during peak demand periods [2]. This emerging capability has fundamentally transformed the traditional role of vehicles from mere transportation devices into active participants in the energy ecosystem, enabling bidirectional energy exchange with electrical infrastructure through Vehicle-to-Grid (V2G) technologies [3]. While the integration of EVs into smart grids presents unprecedented opportunities, it also introduces significant challenges that demand so phisticated modelling and simulation tools to effectively monitor and optimize future deployments [4; 5]. The digital twin technology offers a revolutionary solution to these modelling challenges by creating virtual replicas of physical systems that enable real-time monitoring, analysis, and predictive capabilities [6]. Building on this foundation, the authors have successfully applied digital twin technology across various micro-grid studies and implementations, notably within the PLATOON H2020 EU-funded project [7] and the Smart Mobility Hub Italian initiative, funded by the Italian Ministry of Enterprises and Made in Italy [8]. When applied to electric vehicle and smart grid integration, digital twins unlock exceptional opportunities for understanding complex energy flow patterns, optimizing charging strategies, and enhancing grid stability through intelligent energy management [9; 10]. Moreover, these virtual representations may continuously learn from real-world data, adapt to evolving conditions, and generate valuable insights that inform optimization and control strategies [11]. The foundation for this integration lies in smart grid technology itself, which represents a revolutionary advancement in electrical network infrastructure. By utilizing digital communication and automation, smart grids can detect and respond dynamically to changes in energy supply and demand [12]. These intelligent systems facilitate real-time monitoring, analysis, and management of entire electrical networks while seamlessly integrating distributed energy resources to enhance overall system efficiency [13]. When EVs are incorporated into this smart grid infrastructure, they create a sophisticated ecosystem simultaneously serving multiple critical functions: acting as energy consumers during charging operations, functioning as distributed energy storage systems when parked, and operating as potential energy suppliers [14]. The significance of EV integration extends far beyond simple load addition to the electrical grid. Modern EVs, equipped with advanced battery systems and power electronic interfaces, in fact, spend approximately 90-95% of their operational time parked at various locations with potential charging infrastructure access [15]. This substantial idle time presents remarkable opportunities for grid support services, including peak load management and renewable energy integration [16]. Through coordinated fleet management via intelligent digital twin systems, EVs can provide ancillary services that enhance grid stability and reliability while delivering economic benefits to vehicle owners [17]. On the other hand, it is to be considered that widespread EV adoption introduces critical technical challenges for the grid (grid-to-vehicle, G2V): uncoordinated charging of large vehicle populations can create significant demand peaks that stress existing infrastructure and potentially compromise system reliability [18].