Tokyo Govt to Encourage Offshore Wind Power by Surveying Seabed near Izu Islands

The Yomiuri Shimbu

15:18 JST, March 26, 2026

The Tokyo metropolitan government will conduct a seabed survey necessary for the laying of power transmission cables for offshore wind power turbines near the Izu Islands, a move aimed at encouraging more companies to enter the wind power sector.

The survey will start next fiscal year, which begins in April.

Some companies that had been involved in domestic wind power projects off the coast of Chiba Prefecture and elsewhere withdrew due to poor profitability, so the metropolitan government decided to take the initiative in removing a major barrier to entering this industry. This is reportedly the first such project by a local government in Japan.

The Izu Islands, a chain that extends into the Pacific Ocean south of Tokyo Bay, are part of Tokyo.

At a United Nations conference in 2024, Tokyo Gov. Yuriko Koike announced a plan to develop offshore wind power generation with a capacity of 1 gigawatt, which could provide enough electricity for about 900,000 households. This capacity would be equivalent to the electrical output of a nuclear power reactor.

The Tokyo government expects this wind farm would have floating turbines and selected the Izu Islands as a candidate site with the aim of having the farm operating by fiscal 2035. As well as contributing to Japan’s energy security while being immune to high fuel prices, the wind farm could also supply electricity if power generation capabilities on the nation’s main islands were negatively impacted in situations such as a major earthquake striking directly under the capital.

According to a senior Tokyo government official, such a project would require at least 100 kilometers of power transmission cables. Ordinarily, the companies involved in such a project would shoulder the cost of conducting such a survey. However, calculating profitability in advance was difficult because a full-scale survey would start only after the companies had decided to participate.

In August 2025, a consortium headed by Mitsubishi Corp. withdrew from wind power projects off the coasts of Akita and Chiba prefectures. The companies’ survey revealed complex seabed terrain, and they told the government this required a review of the projects’ design and construction methods.

The Tokyo government will spend about ¥9 billion over two years on compiling a cable-laying plan and conducting drilling surveys. The results will be provided to companies in the hope this information will be used for developing a business plan.

Offshore wind power farms involve either fixed-bottom wind turbines, in which the turbine’s tower is affixed to the seabed, or floating wind turbines that are moored to the seabed and float on the sea’s surface. These farms can generate electricity more stably than onshore wind farms and operate even at night and in rainy weather.

Nine such wind farms operate in Japan, including off the coasts of Hokkaido, Chiba and Nagasaki, and have a total power output of 0.5 gigawatt. Wind power generation currently accounts for about 1% of the nation’s total energy supply mix, but the central government plans to increase this proportion to between 4% and 8% in fiscal 2040.

“The seabed in areas near Japan has a complex topography, and uncertain business costs have been a factor in making companies hesitant to enter these projects,” said Makoto Iida, a project associate professor at the University of Tokyo’s Research Center for Advanced Science and Technology. “Having the Tokyo government step in to conduct this survey makes a huge difference.”