TOKYO — Japan plans to double its regional electrical grid capacity by adding up to 23 million kilowatts, according to a plan compiled by the industry ministry and an organization representing energy operators.
New routes are planned to connect the largest northern island of Hokkaido and the southern island of Kyushu via the main island of Honshu.
The move is aimed at helping Japan reduce greenhouse gas emissions to net-zero by 2050, for which renewable energy sources — including offshore wind — are critical. A major challenge has been weak grid connections traversing regions.
Kyushu, for example, houses solar farms that often have to halt generation due to lack of grid capacity. Japan’s infrastructure has sorely lagged behind Europe, which has cross-border grids that let countries share about 20% of generated electricity to make up for fluctuations in supply.
In Japan, power utilities have monopolized their presence in certain areas, resulting in poor interregional connections. The country’s interregional grid usage was 87.4 billion kilowatt hours in fiscal 2019, only 8.5% of Japan’s total electricity generation.
The Ministry of Economy, Trade and Industry has been working with utility companies to strengthen grid connections. Details and expenditures are expected to be announced later in April.
Japan wants to generate about 130 billion kWh annually from offshore wind sources. This would comprise about 10% of the country’s total electricity output.
New grid infrastructure projects assume that 80% of offshore wind farms would be located in Hokkaido, Honshu and Kyushu. Electricity from these would be sent to metropolitan areas such as Tokyo and Osaka.
Undersea cables would connect Hokkaido with metropolitan Tokyo with a capacity of 8 million to 12 million kW — 10 times greater than current capacity connecting between Hokkaido and Tohoku.
There is also another plan to connect Hokkaido and Honshu via undersea cable, and to connect the northern area of Tohoku and greater Tokyo via landlines. Capacity would also be added between Honshu and Kyushu.
METI plans to revise its plan after formalizing its national energy strategy. Fewer grid additions would be needed if offshore wind farms are not concentrated in Hokkaido, which is far from major energy consumers.
Utility companies would pay for the transition costs, which could cost as much as several trillion yen and result in higher utility bills for consumers under an existing energy law that was amended in 2020.
Construction could start in 2022 at the earliest after obtaining land and finalizing construction plans.