Two of the projects, accounting for 10MW, are in Yamanashi Prefecture, with the first in Kai city scheduled to start operations in August 2013.
Japan is seeing a surge in investment in utility-scale projects, triggered by the release of a generous feed-in tariff on 1 July.
Mitsui and its partners have announced plans to invest 9bn yen ($110m) in utility-scale solar projects across 10 locations in Japan during the 2013 fiscal year, according to Solar Frontier.
Solar Frontier, owned by oil and gas company Showa Shell, says it is also discussing supply of its panels to other Mitsui projects.
The
