Cost of Storage
To determine whether Elestor’s mission (“Reducing electricity storage costs to the absolute minimum”) is indeed accomplished, it is important to have a common understanding of the definition of ‘Cost of Storage’. This obviously goes beyond simply considering the investment costs (Capex) for a particular storage system.
‘Cost of Storage’ is a very important figure because, in essence, it determines the economic value of a storage technology, thus of its market adoption, and finally of its impact on the energy transition.
Over the years, ‘Cost of Storage’ has been quantified in several ways. Today, and particularly with flow batteries stepping forward, the terminology as well as the mathematical approach needs some adjustment.
For flow batteries, the ‘Investment costs per kWh’ is not a fixed number
If, for instance, doubling the storage capacity of a traditional battery is desired, then automatically also the power is doubled. In fact a second complete storage unit is added in this case, obviously also resulting in double investment costs (Capex).
Since power [kW] and capacity [kWh] of traditional batteries have a fixed ratio, the investment costs can simply be expressed in a fixed number of ‘€ per kWh’.
The Capex of such systems is then calculated by multiplying this constant by the desired storage capacity.
This is, however, different for flow batteries. With flow batteries, doubling the storage capacity [kWh] only means : Doubling the volumes of active materials. The system’s power remains unchanged and this then obviously does not result in double investment costs.
The additional costs for doubling the capacity of Elestor’s solution are only marginal, because the active materials (H2 and Br2) were purposely selected for their low cost.