The supercapacitors can handle more than 500'000 charging/discharging cycles during a minimum operating life of ten years with almost no change in their capacitance. Thanks to double-layer capacitors, maintenance cycles and test runs are completely obviated. In addition, double-layer capacitors can be completely discharged, a condition which usually is inconceivable in conventional systems. Care must be taken to ensure short charging times in case of frequent power failures particularly in the UPS sector. In this point too, double-layer capacitors are far superior to conventional batteries
The safest and most advanced solution is the online UPS, which completely decouples the line from the load. Sensitive and highly critical loads such as complex and sensitive manufacturing systems are secured exclusively by such online UPS systems.
During voltage sags or complete interruptions of the power supply, the energy has to be delivered by local energy storage devices. Lead-acid batteries, the conventional energy storage choice for UPS, can not be designed to bridge interruptions that last for seconds vs. many minutes. It is important to note that over 98% of power outages in the low voltage area last less than 10 s. Thus, in contrast to batteries, supercapacitors are ideally suited to fulfill UPS requirements. The strength of supercapacitors lies in their ability to release energy with no delay for periods from a fraction of a second up to 30 seconds.
With their guaranteed low residual current, long operating life, no maintenance or costly test runs, the ability of full discharge and the short recharging times for frequent power failures, supercapacitors are an outstanding storage device as the key function in storing energy in high reliability systems.
Source: Garmanage: Roland Gallay