A unique, environmentally-friendly micron scale autonomous electrical power source is provided for generating renewable energy, or a renewable energy supplement, in electronic systems, electronic devices and electronic system components. The autonomous electrical power source includes a first conductor with a facing surface conditioned to have a low work function, a second conductor with a facing surface having a comparatively higher work function, and a dielectric layer of not more than 200 nm in thickness sandwiched between the respective facing surfaces of the first conductor and the second conductor. The autonomous electrical power source is configured to harvest minimal thermal energy from any source in an environment above absolute zero. An autonomous electrical power source component is also provided that includes a plurality of autonomous electrical power source constituent elements electrically connected to one another to increase a power output of the autonomous electrical power source.