Energy storage by capacitors

The paper presents analytical calculations for a capacitor as an energy storage device, which is discharged with constant power. Calculated are the delivered energy, the energy losses, the residual energy, the voltages and the currents at the beginning and at the end of the discharging process as well as the feasible duration of this process, all in dependence on the delivered power. The per unit values of these quantities are plotted in diagrams with both linear and logarithmic scale. To clarify the fact, that different types of capacitors are adapted for different applications of energy storage, the results of these calculations are applied to aluminium electrolytic capacitors and to double layer capacitors. In addition, the different characteristics of both types are explained by their values of specific energy and specific power.