Japan to spend US$43m on undersea cable feasibility study

According to a Nikkei report, two high-voltage direct current transmission lines linking Hokkaido and Japan's main island of Honshu will increase the total capacity to 1.2 gigawatts (GW) by 2028, but that would not be sufficient.

One solution requires a new undersea transmission line in the Pacific Ocean or the Sea of Japan. The line would connect to either Fukushima Prefecture or Niigata Prefecture, both of which have strong transmission networks that allow electricity to be delivered to the Tokyo metropolitan area.

Hokkaido is expected to produce up to 15GW of wind power, according to the report. Offshore wind turbines are able to generate 10,000 kW each, and 1,400 turbines are planned to be installed across Hokkaido.

Renewables expert Karah Howard at Pinsent Masons said: “The feasibility study is an essential first step towards Japan meeting its onerous offshore wind capacity target from 10 gigawatts in 2030, to 45 gigawatts by 2040, which is equivalent to the power produced by around 45 nuclear reactors. The capacity expected to be generated from Hokkaido is around 15GW, nearly 1/3 of the total power generation by 2040, which indicates the significance of this study.”

“Undersea cables are said to be the most economical solution, compared to overland transmission, given the scarcity of land, and it is estimated that the cost of the total cost of the programme could reach 1 trillion yen,” she said.

In March 2021, Japan’s Ministry of Economy, Trade and Industry (METI) said it would consider plans to lay submarine power cables for offshore wind plants, which in total could cost 1 trillion yen.

In December 2020 the Japanese government set targets of installing 10GW of offshore wind power by 2030 and 45GW by 2040 as part of plans to achieve carbon neutrality by 2050 that Japan's prime minister Yoshihide Suga announced in October 2020.