Thermoelectric energy (or power) harvester is a kind of renewable energy approach that extracts waste heat from targeted device or object to generate electrical power. It is an advance technology widespread among researchers for decades. By having plenty of promising advantages, the thermo-electric power harvester is being developed in types of feasible interfaces. This review paper focused on research had been done relating to thermo-electric power harvester, in the macro scale and mainly in the micro scale of power harvester. Several designs of thermo-electric technologies will be further discussed in this paper. This paper reveals the viability of thermo-electric power harvester in sustaining electric supply for microelectronics applications. Eventually, some add-on is being proposed at the last part of the paper.