It has launched “full-scale operations” at its 54.6MW Akita Port and 84MW Noshiro Port projects off the coast of Akita prefecture.
The projects consist of 33 of Vestas’ V117/4.2MW turbines installed on fixed-bottom foundations.
Both wind farms are now receiving a feed-in tariff.
Marubeni’s partners in the JPY 100 billion ($768 million) project included Obayashi Corporation, Cosmo Eco Power, Tepco and various Japanese utilities.
Japan has launched a tender programme to support 10GW of offshore wind capacity by 2030 and up to 45GW by 2040. However, it had to revise regulations to encourage a wider range of bidders to take part.
Until today, Japan had also not commissioned large-scale offshore winds, though it had commissioned a handful of small demonstration projects.
Marubeni is eyeing a significant role in Japan’s expected offshore wind build-out, teaming with oil major BP to target development.