Thermal self supporting SOFC module was studied under various conditions for high energy conversion efficiency. In order to achieve high energy conversion efficiency even under partial load condition, SOFC module and system was designed to operate at intermediate temperature by using LaGaO(3) based oxide film electrolyte. Heat loss, Q(heatloss) is requested to be diminished as much as possible by decreasing heat radiation and exhaust gas heat from module. SOFC module with 700W was successfully demonstrated in thermal self-supported state under various conditions. SOFC module can be thermally self-supported within a limited temperature range (841-886 K) but energy conversion efficiency decreases with decreasing current density, because of the limited fuel and air utilization from heat value requested for thermal self-support. In this study, the energy conversion efficiency of the 700W module shows ca. 47% low heat value (LHV) at 700W output power with fuel utilization of 75% and even at 250W partial load, efficiency is ca. 30% achieved. For achieving the high energy conversion efficiency in partial load mode and self-thermal supported condition, decrease in heat loss, in particular, 400W is strongly requested. (C) 2011 Elsevier B.V. All rights reserved.