Techno-Economic Analysis of Redox Flow Batteries with Thermal Coupling under Dynamic Tariffs

The increasing share of renewable energy in Germany has intensified electricity price volatility, underscoring the economic potential of energy storage solutions as energy buffers. This study proposes a techno-economic framework to evaluate vanadium redox flow batteries (VRFBs) under dynamic electricity tariffs and photovoltaic (PV) surplus scenarios. The framework integrates an electro-thermal VRFB model with mixed-integer linear programming (MILP) to identify optimal system configurations and operation strategies. Using real load data from a university building, the economic performance of VRFB-only systems and VRFB systems coupled with thermal coupling modules (TCMs) is assessed. Results show that a 50 kWh VRFB with a 75 kW TCM yields a net present value (NPV) of €55,000, while the VRFB-only system achieves an NPV of – €11,000. These findings demonstrate that thermal integration significantly enhances the economic viability of VRFB-based storage solutions.