Tetsunari Iida (飯田 哲也, Iida Tetsunari; born 1959, Yamaguchi Prefecture, Japan) is director of the Institute for Sustainable Energy Policies in Japan. Following the Fukushima nuclear disaster, he is calling for a decrease in Japan's reliance on nuclear power and an increase in renewable energy use. Iida started his career as a nuclear engineer, but he quit in 1992, and went to study renewable energy in Sweden. In September 2011, Iida launched the Japan Renewable Energy Foundation, which is backed by ¥1 billion (US$13 million) from Japan's richest man, Masayoshi Son.