Energy harvesting is the process by which energy is drawn from external sources (solar, wind, thermal, vibration, kinetic, chemical, etc.) in infinitesimal quantities, then stored for use in the autonomous operation of small portable devices such as those of the wearable electronics. Wireless sensor network but also large-scale applications, especially for thermic sources: foundries, space, etc.
Energy harvesting systems generally supply very small quantities of electrical current to low-power electronic circuits, from energy sources present in the environment.
The market for low power (sub-watt) (thermic source) energy harvesting systems was estimated at 100,000 units in 2014 and could reach 9 million units in 2020 and could gradually replace the batteries of portable devices or dynamos on bicycles.