Japanese activities for introducing residential PV systems as a national energy supply

The paper summarizes Japanese activities concerning photovoltaic systems, especially for residential use as a national energy supply. 1994 is just the 20th anniversary of the Sunshine Project, which started in July 1974. In the project the utility-connected, residential applications mounted on roofs have been its major target from an early stage of R&D. It can be considered that technologies for the target have been fundamentally established and a series of new activities have been being introduced to promote the commercialization and diffusion of PV systems. To review those activities, several condensed tables are presented, i.e., R&D history of residential applications, trends in regulation and code improvements, and new institutional activities to spread PV systems. Possible R&D items from now on are also reviewed and listed, which are necessary to support these efforts