The question of environmentally neutral energy generation is becoming ever more urgent. Energy harvesting, which means harvesting small amounts of energy from the surroundings of a device requiring recharging, can be one of the answers. Energy is generated by piezoelectric vibrations, thermoelectrics using temperature differences or with electromagnetic radiation using radio waves.
A smart sidewalk, for example, could absorb the vibrations in the steps taken by pedestrians and convert this into energy for street lights. Smartwatches and other wearables can recharge using body heat. In future, the consumption of finite energy sources could drastically decline thanks to energy harvesting.