The increasing rise in renewable energy sources (RESs) has affected how electricity systems operate. The high level of penetration, particularly in the transmission grids, has the potential to significantly alter the bulk power system and result in unusual frequency variations, which has led to a growing concern regarding frequency instability in the power grid due to intermittent generation and its impact on the demand and generation balance. Energy storage systems can function as a backup power source and offer a range of decentralized auxiliary services. The integration of all-copper redox flow battery with power grids, coupled with real-time hardware-in-the-loop (HIL) testing, represents a significant leap forward in energy storage technology. This innovative approach not only enhances the precision of CuRFB modelling but also enables real-world application by simulating dynamic operating conditions. Through the utilization of HIL testing, researchers and engineers can validate the performance of CuRFB systems across various scenarios, offering invaluable insights for optimizing their design and operation. Furthermore, the application of CuRFB systems in ancillary services, such as Fast Frequency Response (FFR) and Frequency Containment Reserve (FCR), presents a promising avenue for grid stabilization and improved reliability. The flexibility and rapid response capabilities of CuRFBs make them well-suited for providing these critical grid services, thereby aiding in the integration of renewable energy sources and bolstering grid stability. By harnessing the synergy between advanced modelling techniques, real-time testing, and ancillary service applications, CuRFB technology is positioned to play a pivotal role in shaping the future of energy storage and grid management. Additionally, the utilization of CuRFB technology in ancillary services like FFR and FCR offers numerous benefits beyond grid stability. These services contribute to the efficient management of energy resources, enabling utilities to balance supply and demand. By leveraging the scalability and modularity of CuRFB systems, operators can deploy distributed energy storage solutions tailored to specific grid requirements, optimizing resource allocation, and minimizing operational costs. Furthermore, the integration of CuRFBs into ancillary service markets fosters competition and innovation, driving advancements in energy storage technology and accelerating the transition towards a more resilient and sustainable energy infrastructure. In the project-based lab access at the Austrian Institute of Technology (AIT) in Vienna, our focus was on investigating the potential of copper-based Redox Flow Batteries (CuRFB) for frequency regulation services. Central to our approach was the real-time validation of battery models using experimental data obtained from cell diffusion studies. This integration is critical for battery development, enabling researchers and engineers to test and validate the performance of battery management systems (BMS) and other related technologies under realworld conditions without the risks and costs associated with physical prototypes. HIL simulations help in ensuring that the models accurately reflect real-world behaviour, allowing for precise prediction and analysis of how battery systems will perform in actual use. Leveraging the OPAL-RT Hardware-in-the-Loop (HIL) tool, specifically the RT-LAB platform, enabled us to create simulations designed to operate in a real-time environment. Our primary objectives encompassed achieving several key goals: 1. Accurately assessing the performance of CuRFB systems under dynamic operating conditions, validating the effectiveness of our battery models in real-world scenarios based on prequalification test for battery providers in frequency regulation services in power grids. 2. Ultimately evaluating the feasibility of integrating CuRFB technology into frequency regulation services for grid stabilization and reliability. Through this comprehensive approach, we aimed to advance our understanding of CuRFB technology and its potential applications in enhancing the resilience and efficiency of modern energy grids. Primarily Findings 1. Real-time modelling of batteries for power applications demands a high level of accuracy and efficiency to simulate dynamic responses accurately. OPAL-RT HIL tool provides a crucial bridge between hardware and software, enabling seamless integration of physical battery components into real-time simulations, ensuring that models reflect real-world behaviour with precision. 2. OPAL-RT HIL's capability to replicate real-time operating conditions allows for thorough validation of battery models, facilitating the identification and resolution of potential issues before deployment. By providing a platform for rapid prototyping and testing, OPAL-RT HIL accelerates the development cycle of battery systems, enabling engineers to iteratively refine designs and optimize performance for specific power applications.