Pathways toward enhanced techno-economic performance of flow battery systems in energy system applications

Redox flow batteries have shown great potential for a wide range of applications in future energy systems. However, the lack of a deep understanding of the key drivers of the techno-economic performance of different flow battery technologies-and how these can be improved-is a major barrier to wider adoption of these battery technologies. This study analyzes these drivers and provides an extensive comparison of four flow battery technologies, including the all-vanadium redox (VRB), iron-chromium, zinc-bromine, and polysulfide-bromine flow batteries, by examining their current and projected technoeconomic performances. We address the potential for performance improvements and resulting cost reduction by developing a component-based learning curve model. The model considers the near-term learning rates for various subcomponents of each of the four battery technologies as well as their technological improvements. The results show that (i) both technological improvements in the performance parameters as well as mass production effects could drive significant cost reductions for flow battery systems; (ii) flow battery systems could be cost-effective in a variety of energy system applications in the near future; and (iii) from a techno-economic perspective, VRB systems are more suitable for the applications that require low energy and high power capacities.