Photo/Illutration An offshore wind farm will be built near the outer seawall off Noshiro Port in Akita Prefecture. (Yoichi Masuda)

Trading house Marubeni Corp. and 12 other companies on Feb. 3 said they will build Japan’s first large commercial sea-based wind farm in Akita Prefecture and aim to start operations in 2022.

The total cost of the project is estimated at about 100 billion yen ($920 million), and 70 to 80 percent of the funds will be invested by financial institutions in Japan and overseas, they said.

According to the investment agreement signed on Feb. 3, the wind farm will operate in waters off Akita Port in Akita city and Noshiro Port in Noshiro and have a total capacity of about 140 megawatts.

Other companies involved in the project include: construction giant Obayashi Corp; a subsidiary of Tohoku Electric Power Co.; Kansai Electric Power Co.; Chubu Electric Power Co.; and Akita Bank.

Sources familiar with the project said 33 windmills with a capacity of 4.2 megawatts each will be installed in the sea, providing enough electricity to supply 130,000 households.

Based on the feed-in tariff system, the generated electricity will be sold to Tohoku Electric Power over 20 years at a price of 36 yen per kilowatt-hour.

The open ocean provides more favorable wind power conditions than on land.

Overseas, the number of large wind power projects has increased while costs have declined.

But such projects have been delayed in Japan. Demonstration projects around the country currently have a total capacity of only several tens of megawatts.

However, the Japanese government has recently been pushing for more favorable conditions for renewable energy projects.

A law designating promotional sea areas for renewal energy projects took effect in April 2019. The law allows publicly chosen wind-power operators to use such areas for a maximum 30 years.

In December, a sea area off Goto city in Nagasaki Prefecture became the first to receive the designation under the law.

In addition, the number of environmental impact studies have also increased, paving the way for the future commercialization of offshore wind farm projects.

As of August 2019, such projects across Japan were expected to eventually have a total capacity of 13 gigawatts.

Leading general contractors plan to build ships that can assemble windmills at sea. But they have faced opposition from local groups, including fishery operators.