The electric power generated by thermoelectric modules obviously depends not only on the nature of the modules but also on heat transfers on both sides of these modules. In addition to the improvement of the thermoelectric material and module, analysis of thermoelectric systems is equally important in achieving their high-performance. The aim of this study is to investigate the electric power extractable from a system equipped with thermoelectric modules and the influence of operating parameters on electricity generation. A computer model was developed to simulate the performances of the thermoelectric system. The influence of the position of the thermoelectric couples (occupancy rate) along the system was studied in order to optimize electrical power. The results obtained for modules made with Bi2Te3 from two various data sources and with slightly different thermoelectric properties are also presented in the study. Another study was made for automotive application. In this case, the use of various types of modules was considered. In each case the numerical model shows the importance of the 'repartition and choice of thermoelectric couples. It shows that for each thermoelectric fabrication there is an optimal occupancy rate which can vary greatly. (C) 2014 Elsevier Ltd. All rights reserved.