Levelized cost of electricity and greenhouse gas emissions of Ce- and V-based redox flow batteries

Inexpensive energy storage technologies are critical to meeting rising renewable electricity demand and maintaining grid stability, but there is insufficient storage capacity to meet this demand. Redox flow batteries are a promising long duration (>10 h) storage method because they scale efficiently with delivery time compared to non-flow batteries. Because of the connection between energy storage and intermittent renewables, the greenhouse gas emissions associated with using flow batteries are important to consider. Here, we investigate the all-vanadium redox flow battery and a Ce–V battery, where the V4+/V5+ couple is replaced by Ce3+/Ce4+. We use performance metrics from the literature and our previous work to model the batteries' operation. We develop technoeconomic assessment and life cycle inventory models and determine that the Ce–V RFB minimum levelized cost of electricity is lower and the two RFBs’ levelized GHG emissions are similar, suggesting Ce should be considered further in RFB applications. Ultimately, the production of the RFBs results in minor emissions compared to use, except in scenarios where 100% renewables are used to generate electricity. The redox potential and exchange current density are highly influential to the Ce–V RFB cost and emissions, motivating further work into the phenomena that control thermodynamics and kinetics. •Technoeconomic and life cycle inventory shows Ce competitive with V flow batteries.•Minimizing CO2 results in lower operating current density than when minimizing cost.•Largest factors in decreasing costs are redox potential and faradaic efficiency.•V2O5 precursor cost for VRFBs, and Ce kinetics for the Ce–V RFB are also important.