Japan’s First Large-Scale Offshore Wind Farm Swings into Service in Akita

Japan marked progress toward its green energy transition with the start of a new offshore wind farm at Noshiro Port in Akita Prefecture. The 20 turbines went online on December 22, 2022, making it the first such large-scale facility in the country to begin producing electricity commercially. The farm, operated by the Akita Offshore Wind Corporation with backing by major Japanese trading house Marubeni and others, is part of a larger project that includes another 13 turbines at Akita Port that are slated to begin operation in January 2023. The start is the culmination of a 7-year effort that got underway with a feasibility survey in 2015 and brings Japan one step closer to making wind power a key component in its shift to renewable energy sources.

The large, bottom-fixed turbines are made by Danish manufacturer Vestas, a major producer of wind turbines, and are capable of providing stable power generation in differing weather conditions. Located 1–3 kilometers off the coast, the turbines boast a rotor diameter of 117 meters, with the blades at their apex reaching a height of 150 meters above the sea surface, equivalent to a 40-story building. Each unit can produce 4,200 kilowatts of power, and together they will generate up to 140 megawatts, enough to power roughly 130,000 Japanese households. The electricity from the turbines will travel through a series of onshore substations of the Noshiro Thermal Power Plant and then on to the local power grid. Under a power-purchase agreement, the utility Tōhoku Electric will sell the electricity generated by the farm for 20 years at ¥36 per kilowatt hour based on Japan’s feed-in tariff program for renewable energy.

The Noshiro Port offshore wind farm is part of a renewable energy project developed by AOW and a 13-firm consortium led by Marubeni that includes Tōhoku Electric, Akita Bank, and builders Ōbayashi Corporation and Ōmori Construction Corporation. Ground was broken on the project in February 2020 following the completion of a feasibility study, with work on the cable and other onshore elements completed in September 2021. The anchoring of monopiles on the seabed and fitting of transition pieces was carried out from May to July 2021, and the installation of towers from July to August, atop of which set the nacelle, containing the gearbox and other core components, and turbine blades.

Towers, nacelles, and blades for the 20 turbines were installed by the SEP (self-elevating platform) vessel Seajacks Zaratan, which made a total of five round trips from Akita Port’s Iijima Wharf during construction. To save cost and time, towers were delivered in two halves and assembled at the wharf before being transported to the offshore site. Work was carried out around the clock, with an average of one turbine being completed per day. AOW conducted trials of the turbines in August 2022.

As few Japanese manufacturers produce large turbines like those used in the ¥100-billion project, AOW had to import the majority of components, including monopiles manufactured in the Netherlands and German-made blades, driving up costs. However, installation was carried out in collaboration with several Akita-based firms, bringing over ¥10 billion in revenue to companies in the prefecture.

The project has drawn broad attention as the first of its kind in Japan and is being used as a model for other ventures. One of these is a project led by Mitsubishi Corporation Energy Solutions for wind farms in the general-sea-area off the coast of Noshiro, Mitane, and Oga. Construction on the wind farms is slated to start in March 2026 with an eye to starting commercial operations in December 2028. As a designated site of one of Japan’s four offshore wind projects, the area around Noshiro Port is likely to remain a hotspot for wind power.

With the Noshiro Port wind farm up and running, AOW now turns its eyes to flipping the switch on the turbines at Akita Port. President and CEO Okagaki Keiji, who while at Marubeni worked as project manager on an offshore wind power project in the North Sea in Britain, lauds the project as paving the way for similar undertakings. “It serves as a benchmark for boosting offshore wind power in Japan,” he declares. “Going forward, I hope it serves as a starting point in shifting the country’s energy mix.” He also expressed AOW’s commitment to further developing Akita’s offshore energy potential and training experts in the wind power industry.

A reception to celebrate the completion of the project is scheduled for March in Noshiro.

(Originally published in Japanese on Kyōdoshi.com on December 23, 2022. Translated and edited by Nippon.com. Banner photo: The Noshiro Port wind farm. © Hokuu Shimpō.)

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