Japanese giant Mitsui & Co. will invest €575m ($630m) to take a big stake in Mainstream Renewable Power, joining majority owner Aker Horizons in a mission to turn the developer into a “renewable energy major” spanning wind, solar, storage and clean fuels.

Mitsui – one of Japan’s largest conglomerates with power generation interests in 22 countries – will own 27.5% of Mainstream following the deal, which values the developer at €2.1bn, alongside Aker Horizons with 54.4%.