text: The technical merits make redox flow batteries a well-suited option for large-scale energy storage. Flow batteries are normally considered for relatively large (1 kWh – 10 MWh) stationary applications with multi-hour charge-discharge cycles. Flow batteries are not cost-efficient for shorter charge/discharge times. Some examples of flow battery market niches are:
  * Grid energy storage - short and/or long-term energy storage for use by the grid
  ** Load balancing – where the battery is attached 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.
  ** Shifting energy from intermittent sources such as wind or solar for use during periods of peak demand.
  ** Peak shaving, where spikes of demand are met by the battery.
  * 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), the electrolytes may be charged using a given number of cells and discharged with a different number. As battery voltage 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.
  * 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. A common problem found with most RFB chemistries in the EV applications is their low energy density which translated into a short driving range.  Zinc-chlorine batteries and batteries with highly soluble halates are a notable exception.
  * Stand-alone power system – An example of this is in cellphone base stations where no grid power is 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.