Load balancing – where the battery is connected to an electrical grid to store excess electrical power during off-peak hours and release electrical power during peak demand periods. The common problem limiting the use of most flow battery chemistries in this application is their low areal power (operating current density) which translates into a high cost of power.
Storing energy from renewable sources such as wind or solar for discharge during periods of peak demand.[38]
Peak shaving, where spikes of demand are met by the battery.[39]
UPS, where the battery is used if the main power fails to provide an uninterrupted supply.
Power conversion – because all cells share the same electrolyte/s. Therefore, the electrolyte/s may be charged using a given number of cells and discharged with a different number. Because the voltage of the battery is proportional to the number of cells used the battery can therefore act as a very powerful DC–DC converter. In addition, if the number of cells is continuously changed (on the input and/or output side) power conversion can also be AC/DC, AC/AC, or DC–AC with the frequency limited by that of the switching gear.[40]
Electric vehicles – Because flow batteries can be rapidly "recharged" by replacing the electrolyte, they can be used for applications where the vehicle needs to take on energy as fast as a combustion engined vehicle.[41][42] A common problem found with most RFB chemistries in the EV applications is their low energy density which translated into a short driving range. Flow batteries based on highly soluble halates are a notable exception.[43]
Stand-alone power system – An example of this is the telecom industry for use in cellphone base stations where there is no grid power available. The battery can be used alongside solar or wind power sources to compensate for their fluctuating power levels and alongside a generator to make the most efficient use of it to save fuel.[44][45] Currently, flow batteries are being used in solar micro grid applications throughout the Caribbean