Japanese gas utilities have been conducting demonstration and field tests of on-site PAFC power generation plants for more than two decades since Tokyo Gas and Osaka Gas first participated in the TARGET Program launched in the US in 1967. Total capacity of plants installed and tested to dale has amounted to 15.56 MW. Cumulative number of installed plants has reached a total of 106, As of the end of August 1999, totalled 45 plants with a total capacity of 7800 kW are in operational. During the recent 2 years since the last Grove Symposium, 11 plants (three for Tokyo Gas and eight for Osaka Gas) surpassed the 40,000 h durability target set as the R,D&D target for fuel cell technology. To date, two plants have logged an uninterrupted run of over a full year, the other target set as the reliability index.