The Case for a Korea-Japan HVDC Power Link
South Korea and Japan rank last and second-to-last respectively in Roger Pielke's Energy Security Index for G20 nations, the case for a bilateral HVDC power grid connection between the two countries is now being made with fresh urgency.
Connecting the two grids would allow shared use of backup generation and energy storage infrastructure, improving utilisation rates and reducing the investment burden on each country individually. Solar and wind variability is partly a function of geography and time zones - the time difference between Korea's easternmost and westernmost points is just 12 minutes, but a Korea-Japan interconnection would extend the shared power zone's effective time spread to 80 minutes, improving flexibility and smoothing wind fluctuation. During extreme weather events or grid emergencies, combined reserve capacity from both countries would increase overall reliability.
Cross-border HVDC submarine links are well established. The UK-Denmark Viking Link - 765 km, 1.4 GW - was completed in 2023 in four years at a cost of $1.9 billion. In Northeast Asia, SoftBank's Masayoshi Son proposed an "Asia Super Grid" linking Mongolia, China, Korea and Japan following the 2011 Fukushima accident, though this broader regional concept has remained at the policy discussion stage.
Korea already operates three HVDC submarine cables between Jeju Island and South Jeolla Province. The most recent, the 200 MW Wando–East Jeju link, required 96 km of HVDC cable, two converter stations, and a budget of 470 billion won, completed in two years.
A full Northeast Asia grid involving China and Russia is considered geopolitically unrealistic at present. A Korea-Japan bilateral link is not. Public sentiment between the two nations is currently favourable, and a route connecting Korea's southeastern region to Japan's Kyushu or southwestern Honshu would span approximately 250 km.
The comparison to European integration has been made explicitly: Korea Chamber of Commerce and Industry chairman Chey Tae-won has argued through multiple channels that Korea and Japan should pursue economic integration approaching the level of the EU - itself an entity that began with the 1952 European Coal and Steel Community. A power grid connection, the argument goes, could serve as a similar founding infrastructure for deeper bilateral prosperity.
