# Hybrid Wind-Redox Flow Battery System for Decarbonizing Off-Grid Mining Operations
## 1 Introduction
[29] examined the integration of a flow battery system to address the intermittency of renewable energy sources while managing fluctuating energy demand. The proposed energy system featured a hybrid setup comprising a partially covered parabolic mirror thermal photovoltaic collector, a vanadium redox flow battery, thermal energy storage, and an absorption chiller/heat pump. Their comparative analysis between a VRFB-based system and a Power-to-Hydrogen-to-Power (P2H2P) system revealed that the VRFB system achieved an exergy efficiency of 78.52%, outperforming the P2H2P system, which had an efficiency of 41.73%. [PERSON] et al. [30] explored the feasibility of powering an air-source hybrid heat pump using a vanadium redox flow battery-based energy storage system. Their study selected two key performance indicators: exergy destruction and exergy efficiency. Using a MATLAB Simulink model, they analyzed a system where solar photovoltaic panels and wind turbines charged the VRFB. The results showed that integrating wind turbines with the VRFB was more effective, as the photovoltaic-based system exhibited significant exergy destruction and lower exergy efficiency. In a different study, [PERSON] et al. [31] presented a load frequency control model for a wind power system and redox flow battery storage. Their findings demonstrated that frequency-based VRFB modeling yielded superior performance compared to conventional VRFB modeling techniques, highlighting the potential of flow batteries in enhancing grid stability. Among the different types of flow batteries, all-vanadium redox flow batteries (VRFBs) stand out due to their flexibility, adaptability, and scalability. [PERSON] and [PERSON] [32]  
Figure 2: Flow battery in a renewable energy microgrid [25]. investigated redox flow battery technology for energy storage and clean hydrogen production, integrating VRFBs with catalytic reactors to enhance efficiency. [PERSON] et al. [33] estimated the overall efficiency of such systems to range between 70% and 85%, while [PERSON] et al. [34] reported efficiencies exceeding 83%, a value often used as a benchmark for sizing battery systems. One key advantage of all-vanadium flow batteries is their ability to independently scale storage capacity and power output. [PERSON] and [PERSON] [35] and [PERSON] et al. [36] emphasize that increasing storage capacity is directly proportional to the electrolyte volume, necessitating larger electrolyte reservoirs for extended operation. [PERSON] et al. [36] further highlight that increasing the battery's storage capacity and cycle duration can effectively reduce capital expenditure (CAPEX) per kilowatt-hour, improving the economic feasibility of large-scale deployments. The economic viability and resilience of hybrid energy system solutions depend on a comprehensive evaluation of economic and reliability factors during the design phase [37]. In the literature, numerous studies have investigated the investment costs and financial feasibility of redox flow battery (RFB) storage systems for large-scale energy applications. [PERSON] et al. [38] classify two primary approaches to the techno-economic analysis of RFBs: The first focuses on material and investment costs. In contrast, the second incorporates Levelized Cost of Storage (LCOS) models to assess long-term financial sustainability. [PERSON] [26] conducted a detailed techno-economic study on redox flow batteries, demonstrating that capital and operational costs, combined with projected energy throughput, are key determinants of LCOS. According to IRENA [39], the costs of vanadium and zinc/bromine flow batteries could decline by more than 60% over the next two decades, driven by technological advancements and growing market interest. Similarly, [PERSON] et al. [40] predict a steady reduction in redox flow battery costs due to economies of scale and material innovations.