Alkaline zinc-iron flow batteries attract great interest for remarkable energy density, high safety, environmentally benign. However, comprehensive cost evaluation and sensitivity analysis of this technology are still absent. In this work, a cost model for a 0.1 MW/0.8 MWh alkaline zinc-iron flow battery system is presented, and a capital cost unde. ••A cost model for alkaline zinc-iron flow battery system is developed.••A capital cost under 2023 DOE's cost target of 150 $ kWh−1 is obtained.••A low flow rate, thin electrodes, and a PBI membrane can lower the capital cost.••Slight impacts on the capital cost is demonstrated at high current densities.Zinc-iron redox flow batteryLarge-scale energy storageSystem costSensitivity analysisa specific electroactive area (m2 m−3)c concentration (mol m−3)C special coefficientd diameterD diffusion coefficient (m2 s−1)E0 To address the pollution, rising energy costs, and climate change caused by the intensive use of fossil fuels, tremendous attention has been paid to alternative, renewable energy such as solar and wind energy,,. For instance, 95% of new energy consumption in Europe from 2005 to 2030 will come from renewable energy sources. However, the intermittent and unreliable characteristic of this kind of energy triggers the pursuit of energy storage technologies with competitive cost and high reliability,,,.Flow batteries, of which the energy and power can be designed independently, combine excellent traits of great safety, high efficiency, and durable cycle life, becoming a promising candidate for the back power of renewable energy sources,,. Since Thaller proposed the first iron-chromium (Fe-Cr) flow battery in 1975, various kinds of flow batteries have been invented and advanced, for instance, all vanadium (V-V) flow batteries,,,,,,,,, zinc-based flow batteries,,,,, iron-based flow batteries,,,,, and polymer-based flow batteries,,,,. To balance the variability of electricity load and meet the rapid growth of energy needs, energy storage over GWh magnitude is pursued. The U.S. Department of Energy (DOE) proposed a long-term target for energy storage technologies of a system capital cost under 150 $ k.
