Real time testing of copper-based redox flow batteries performance for frequency regulation service in power grids (RTT-Flow)

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 intermit
tent generation and its impact on the demand and generation balance. Energy storage sys
tems can function as a backup power source and offer a range of decentralized auxiliary ser
vices. 
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 Frequen
cy Response (FFR) and Frequency Containment Reserve (FCR), presents a promising ave
nue for grid stabilization and improved reliability. The flexibility and rapid response capabili
ties of CuRFBs make them well-suited for providing these critical grid services, thereby aid
ing 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 of
fers numerous benefits beyond grid stability. These services contribute to the efficient man
agement 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 tech
nology and accelerating the transition towards a more resilient and sustainable energy infra
structure.  
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 perfor
mance of battery management systems (BMS) and other related technologies under real
world conditions without the risks and costs associated with physical prototypes. HIL simula
tions 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 po
tential 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 accu
racy and efficiency to simulate dynamic responses accurately. OPAL-RT HIL tool pro
vides 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 thor
ough validation of battery models, facilitating the identification and resolution of poten
tial issues before deployment. By providing a platform for rapid prototyping and test
ing, OPAL-RT HIL accelerates the development cycle of battery systems, enabling 
engineers to iteratively refine designs and optimize performance for specific power 
applications.