A good example of a cycling application is one used for energy recovery, such as regenerative braking. Here the advantages of hundreds of thousands of cycles can be seen. Also, the very low equivalent series resistance (ESR) of a supercapacitor allows for very high round trip (charge & discharge cycle) efficiency, in the range of 97%+ values. Compared to the cycle life of batteries in the thousands, and round trip efficiency in the mid-80% range, this is a significant advantage. Some applications combine batteries and supercapacitors to take advantage of the strengths of both. In these cases, the supercapacitors are used for regeneration, where the higher efficiency and large number of cycles can be utilized, and the batteries for long term energy needs, where their higher energy density is an advantage.


Power Backup

Supercapacitors are well suited for power backup applications, especially where battery replacement and maintenance cost is very high, or where very long life, and stable, predictable aging is needed. In power backup applications, energy requirements need to be low because of the low energy density. A good rule of thumb is for energy requirements of 60 seconds or less. An exception to this is where the backup power requirement is very low, such as in electronic applications. A good example of a power backup application is that used in Wind Turbines, for power in an emergency pitch. In this example, power is needed for about a half-minute when utility power is lost to the wind turbine, and the blades need to be turned to stop the rotor. Replacement cost is high, as the batteries are located up the tower in the hub. It is a two person task that takes a half-day to accomplish.


Pulse Power

Pulse power applications take advantage of the low equivalent series resistance of supercapacitors, that is, their ability to deliver large amounts of power very quickly. Pulse power applications can be mobile medical equipment, engine starting uses, voltage & frequency stabilization deployments, or systems to drive huge short term power needs from low or limited power sources. Pulse power applications can also be coupled with power backup to provide power quality and stability to a variety of industrial applications.