Supercapacitors provide peak power
A supercapacitor stores far more energy than traditional batteries and has far superior power delivery to batteries that are limited by the rate of a chemical reaction, or energy harvesters that are limited by ambient power. In applications where significant energy with high peak power is required, a supercapacitor can be the perfect solution.
Supercaps deliver peak power for data transmission, solenoid activation, e-ink update, LED flash etc.
Peak or pulse power loads in an application occur when the peak power is >> average power. The peak bursts occur for a short duration between longer intervals at low power. The energy source, such as a battery or energy harvester can supply the average power but not the peak, which the supercapacitor delivers. Examples include data transmission, activating a solenoid for door locks or for closing or opening a valve, activating a motor for haptic feedback, or to drive a pump for insulin injection or other drug delivery, high power LED Flash, scanners, updating an e-ink display. These actions occur at low duty cycle, with long periods of low power consumption between peak busts. Consider an example of cellular data transmission using LTE CAT M1, which requires 0.2A at 3.6V for NB IoT for 50ms every 60secs, and the power drawn between transmissions is 0.1mA. Then the peak power = 0.72W but average power = (0.72W x 0.05s + 0.36mW x 60s)/60.05s = 0.96mW. A low power energy source such as a coin cell or micro energy harvester can charge the supercapacitor at ~1mW while the supercapacitor provides the 0.72W peak.
For more details see Application Brief Supercapacitors Provide Peak Power.