日本の太陽電池産業の衰退要因

――原料供給の観点からの考察――

抄録

Until approximately 2006, Japan led the world in solar cell technology, practical application, and production. However, around 2020, major domestic solar cell manufacturers withdrew one by one from cell and module production, resulting in a significant reduction. This is because Japan lost its competitiveness against China’s cost-effective products. In general, the competitiveness of Chinese goods is equated with their low labor costs. However, the solar cell industry in Japan has been declining owing to several inherent factors.

Specifically, the failure of the Solar Grade Silicon （SOG-Si） supply system contributed significantly to the decline of domestic solar cell manufacturers. Japan’s solar cell industry recognized the importance of securing SOG-Si from the earliest stages of its development and pushed for its practical application. However, Japan was unable to establish a SOG-Si production system. Meanwhile, although China started working on SOG-Si approximately 10 years after Japan, it quickly established a cost-effective mass production system.

This study investigates the history of Japan’s SOG-Si supply efforts and the impact of their failures, including China’s SOG-Si supply system.