Murubeni said the 100 billion yen ($921 million) plan to build the wind farms with 140 megawatt capacity at Akita Port and Noshiro Port in Akita prefecture was expected to be Japan's first large-scale commercial offshore wind power project.

The work, expected to be completed in 2022, includes building offshore turbines fixed to the sea floor, as well as onshore substation and transmission lines.

Noshiro Port will be the base for operations and maintenance, it said.

Loan agreements to finance the project were secured with domestic and foreign financial institutions. MUFG Bank Ltd, Mizuho Bank Ltd and Sumitomo Mitsui Banking Corp jointly acted as the mandated lead arrangers, Marubeni said.

A Marubeni spokeswoman declined to give a value for the project finance.

Power from the wind farms will be sold to Tohoku Electric Power for 20 years under a power purchase agreement based on the feed-in tariff programme.

Marubeni's 12 partners include Obayashi Corp, Tohoku Sustainable & Renewable Energy Co, Cosmo Eco Power Co, Kansai Electric Power Co and Chubu Electric Power Co.

(Reporting by Yuka Obayashi; Editing by Edmund Blair)