A high efficiency, modular planar SOFC module using the patented CPn module has been demonstrated on pipeline natural gas. The results of this 1.4 kW thermally integrated module, along with stack/cell tests, have verified the multi-stage oxidation concept. Design and analysis of a 10 kW mobile electric power generating system using this technology predicts a final module with 40% system efficiency when operated on logistics fuel. However, this analysis also stresses the need for improved cell performance at lower temperature. Ceria-based planar single cells have been demonstrated at 300 mW/cm 2 at 750°C.