SoftBank Corp.'s clean-energy unit and a partner will build a 100-megawatt wind-power station off the coast of Ibaraki Prefecture.
The project will be developed by Wind Power Energy Co., in which SoftBank unit SB Energy Corp. holds a 49.9 percent stake, according to a statement. Komatsuzaki Group, an Ibaraki-based wind developer, holds the remainder of Wind Power Energy.
SoftBank said in April that the company intended to invest in an offshore wind project by Wind Power Energy. The move would be SB Energy's first investment in offshore wind, Kenichi Yuasa, a SoftBank spokesman, said at the time.
The first phase of the Ibaraki project will comprise 20 5-megawatt turbines, according to the statement, which said the project will be the largest commercial offshore wind farm in Japan.
Japan is pushing the development of offshore wind to increase clean-energy capacity. Earlier this year, the government set a higher tariff for offshore wind than for onshore projects to boost the technology.