The Penetration of Micro CHP in Residential Dwellings in Japan

Micro CHP systems having capacities of only 1 kW and incorporating gas engines or fuel cells have been commercialized for use in residential dwellings in Japan. More than 30,000 micro gas engine CHP systems and 1,250 fuel cell CHP systems have been installed by the end of 2006. The micro gas engine CHP system is a commercial success. The Japanese government has initiated deployment programs to encourage the penetration of residential fuel cell CHP systems in general homes; these systems are equipped with proton exchange membrane fuel cells (PEMFCs). The government subsidizes half or two-third of the initial cost of the residential fuel cell CHP systems. Micro CHP systems are expected to stabilize the distribution grid and improve the reliability of the electricity supply by functioning as controllable distributed energy resources (DER). The outlines of the micro CHP systems, including typical specifications, support programs of the Japanese government, major challenges, and future prospects, are reported.