Ultracapacitors offer many benefits, including (1) reliable interim power even if the primary power source fails or fluctuates, (2) high-energy storage from low-power sources to enable support for high power loads, and (3) peak-power supply to loads while drawing average power from sources. This means that using ultracapacitors in any application reduces the size and weight of the primary power source, improves run time and battery life (particularly at cold temperatures), enables more power-hungry features to be used more often, protects against accidental power loss or fluctuations/interruptions, removes the need for product replacement, and is environmentally friendly.

Applications benefiting from ultracapacitor characteristics include regenerative braking and other quick-charge scenarios such as those in toys and tools. Some applications are well suited for combination battery/ultracapacitor systems, where designs can be optimized to prevent battery oversizing for power demands. Examples include applications in consumer electronics such as digital cameras, in which an inexpensive alkaline battery is combined with an ultracapacitor, and automotive applications such as hybrid power trains.