This study aims to compare a silicon ThermoElectric Generator design (TEG) with a commercial TEG made of BiTe alloy commercialized till recently by Micropelt. The objective is to show that recent advances in heat conduction modulation by silicon planar nanostructures may potentially improve thermoelectric performance of silicon to a competitive level with respect to conventional materials. To that end a planar converter architecture is proposed and modeled by Finite Elements Method and an analytical model based on thermal conductivities reported in the literature. Results show the absence or with a small capacity heat sink. This opens the way to the proposal of TEG based on Si material and compatible with mass production facilities of semiconductor manufacturers.