Hybrid thermoelectric conversion (HTC) has been used as a means to improve the efficiency of high performance mobile computing systems. HTC utilizes the thermal margin in the cooling solution, when the electronic component is not fully active, to integrate a thermoelectric (TE) module into the heat dissipation path for energy scavenging. When the component is driven to its junction temperature limit through a heavy workload, the same TE module is switched to refrigeration mode to provide additional cooling headroom for improved performance. A set of semi-realistic system usage assumptions and parameters has been utilized for the evaluation of HTC in system environments. Results from finite-element analysis (FEA) simulation of the topology and full TE characterization are presented. Common TE models are then used to build an iterative system solver to estimate up to 10% system efficiency benefit from HTC integration using characterized off-the-shelf TE components.