The power generated depends on the type of harvester, its size, and the environment.
For example, in the case of Photovoltaic energy harvesting, the output power will depend on the size of the photovoltaic cell, the light intensity, and the PV cell technology used.
- Indoor Photovoltaic energy harvesting generates power in the range of hundreds of microwatts. (These values may vary depending on the size of the cell.)
- Outdoor Photovoltaic energy harvesting generates power that can reach tens of milliwatts. (These values may vary depending on the size of the cell.)
Other types of harvesters include thermal, RF, and vibration harvesters.
- Thermal energy harvesting (TEG) relies on temperature differences and typically generate power in the range of a few microwatts to several milliwatts, depending on the thermal gradient and the efficiency of the thermoelectric materials.
- RF (Radio Frequency) harvesting capture energy from ambient radio waves, such as those emitted by Wi-Fi, GSM, or TV signals. The power levels are usually very low, often in the microwatt range, and highly dependent on the distance from the emitter and the frequency band.
- Vibration or piezoelectric harvesters convert mechanical vibrations into electricity. The harvested power can vary from a few microwatts up to several milliwatts, depending on the frequency and amplitude of the vibrations as well as the mechanical structure of the harvester.
Each harvester type has its strengths and limitations, and the choice depends on the available energy in the environment and the application’s power requirements.