NYK, as a member of a consortium of four companies, has been selected by Japan’s New Energy and Industrial Technology Development Organization (NEDO) in an open call for applications related to the "Development of basic technologies for a multi-purpose and multi-terminal high voltage direct current transmission system,” in addition to the “development of construction methods for the installation of cable protecting system, etc.” and the “development of new cable-laying vessels, etc.”

To transmit wind-power-generated electricity from suitable locations such as Hokkaido to areas in high demand for electricity, strengthening the power system is necessary, and long-distance subsea DC transmission is considered promising. This project will develop essential technologies such as cable-protection methods and cable-laying vessels that address sea and weather conditions unique to Japan, aiming to reduce the cost of grid reinforcement and shorten the construction period.

To improve the ratio of renewable energy in Japan, the introduction and expansion of wind-power generation at sea and around remote islands, where wind conditions are good and location restrictions are relatively low, are essential. However, areas in Japan suitable for wind power generation, such as Hokkaido, Tohoku, and Kyushu, are far from areas with great electricity demand. Therefore, as wind-power generation grows, transmitting power having the capacity of the existing power system is expected to take more work.

To address this issue, strengthening the power system will be necessary. In particular, constructing long-distance subsea DC transmission, which has less transmission loss than AC and is advantageous for long-distance power transmission in terms of transmission line cost, is considered a promising measure, and its early development is desired.

However, on sea routes from Hokkaido and other areas to the areas with significant demand, it is estimated that cables will need to be laid on bedrock where they cannot be buried, according to previous surveys by NEDO. Therefore, installing ducts to protect the cables is required, which will extend the construction period and increase costs. For this reason, it is essential to reduce the cost of construction methods for protecting cables and to develop technologies such as cable-laying vessels and their outfitting equipment that can respond to Japan-specific sea conditions and weather.

In this project, NEDO has been working on the technological development of a multi-purpose and multi-terminal high voltage direct current transmission system that can efficiently connect multiple offshore wind-power generation facilities to the power systems and can be used as an interregional interconnection line connecting different supply areas. At this time, NEDO has adopted one technological development theme related to laying subsea DC cables.

In this project, NYK will be responsible for developing DC cable-laying vessels. Through this development, NYK will help realize the introduction and expansion of wind-power generation through an electric power system that can efficiently transmit power from suitable locations for wind-power generation, such as Hokkaido, to areas having great demand for wind-generated power. NYK will contribute to achieving by 2030 the renewable energy ratio (about 36 – 38%) outlined in the "Sixth Strategic Energy Plan."

1. Project name: Development of basic technology for a multi-purpose and multi-terminal high voltage direct current transmission system; development of construction methods, such as the installation of pipes to protect cables; and development of essential technologies, such as new cable-laying vessels

2. Budget: Approximately 1 billion yen (FY2023)

3. Period: FY2023 – FY2025 (planned)

4.Participating companies:
　Sumitomo Electric Industries, Ltd.
　Furukawa Electric Co., Ltd.
　NYK Line
　Mitsui O.S.K. Lines, Ltd.