Mitsubishi Materials Corporation and The Kansai Electric Power Co., Inc. have been jointly developing intermediate-temperature solid oxide fuel cells as stationary power generation units since 2001. High performance LSGMC cells and a unique seal-less cell-stack design enable high efficiency operation at temperatures below 800°C. The lst long-term durability test over 4,200 hours of the 4th generation lkW-class module was ended in 2006 with a voltage degradation rate of about 0.5%/1000hours. And the 2nd durability test and output fluctuation tests were conducted in 2007. Scaling-up of the module toward l0kW-class has been successfully done and the electrical efficiency of 50% HHV on DC output was achieved in 2006. The first field test of l0kW-class CHP system was performed in 2007.