In this paper, the application of COTS (Commercial of-the-shelf) TEGs (Thermoelectric Generator) of Bi2Te3 type for power supply of autonomous sensors has been investigated. Architecture of a TEG system has been established and the expected electrical power provision has been simulated and tested with agreement better than one order of magnitude between simulation and test. During the mission the heat flow of the TEG may reverse, therefore this has to be taken into account in the design of the corresponding electrical circuits. TEG sensitivity to low temperatures (below 0 degrees C) has been found and addressed via selection of different COTS TEG types which were tested without any problems down to -10 degrees C. A concept for central provision of electrical power with TEGs has been discussed shortly that showed the need for new high temperature TEGs which can operate on temperatures above 700 degrees C. (C) 2015 Elsevier Ltd. All rights reserved.