Initial concept would see transmission cables extend along the Pacific Ocean side from Hokkaido in the north to the greater Tokyo region. This could offer cost savings compared with cables on land for transmitting electricity generated offshore to where it is needed. If Japan moves forward with the program, it would be following the lead of Europe, where there are several high-voltage direct-current cables that are tens or hundreds of kilometers long. Total cost of the program could reach 1 trillion yen ($9.2 billion).
A goal of net-zero greenhouse gas emissions for Japan by 2050. To reach that target, Japan will need to use more renewable energy in the power sector, which accounts for about 40% of the country’s emissions. The island nation has the scope to expand offshore wind farms. A government-backed target aims to have up to 45 gigawatts — equivalent to 45 nuclear reactors — of offshore wind power capacity by 2040. One bottleneck to expanding renewables in Japan is the limited interconnections between regional power grids. This limitation makes it difficult to transmit power from where it is generated to where it was needed. Laying cables underwater is considered cheaper than doing so over land, which requires expensive and time-consuming negotiations in land-scarce Japan.