Ren Inagawa

Comparison of Offshore Wind in National and Major Country Waters for Offshore Wind Power

Naoyuki Inukai

Currently, in the waters surrounding Niigata Prefecture, the offshore areas of Murakami City and Tainai have been designated as an offshore wind power generation promotion area, and a project operator has been selected in December 2023. In addition, previous results have shown that the offshore of Sado City may also have favorable conditions for offshore wind power generation compared to other areas in Japan. As a result, the seasonal fluctuation of wind speed in Japan is large, and there is concern about the reduction of wind power during the summer season. The installed capacity utilization rate is as high as 50% in winter at some sites, similar to that in Europe, but the poor summer figures make the wind turbines used for comparison in this study unsuitable. The wind turbines actually installed in the promotion zone in Japan are large and highly efficient wind turbines with a generating capacity of 12 MW to 18 MW, so the facility utilization rate is expected to actually improve. The wind direction is more likely to be aligned with the direction of the monsoon and the direction of the land and sea winds, which makes it easier to obtain wind energy efficiently, but not off Sado City. Therefore, it is necessary to understand the wind direction characteristics in detail and to construct a system that can acquire wind energy efficiently. The water depth off the coast of Sado City is more than 100 m, making it suitable for floating offshore wind turbines. In addition, the frequency of high waves is higher in the waters off the Sea of Japan than in Europe, China, and Taiwan, and therefore design criteria should be set higher. The swell characteristics were similar for the Sea of Japan side and Europe, with a tendency for medium or long swells to increase during the winter season. Wave direction differs depending on the area, and unlike wind direction, no waves are generated from the land side. The results indicate that the offshore area of Sado City, Niigata Prefecture, has the same or even greater potential for offshore wind power generation than the offshore areas of Murakami City and Tainai City, which are also in the vicinity of Niigata Prefecture.