High-voltage submarine power cables carry electricity across seas and oceans, connect offshore renewable projects to onshore grids, link islands to mainland networks, and enable countries to trade power more efficiently.
The growth of this infrastructure is being driven by the rapid expansion of offshore wind farms, the need for long-distance renewable integration, and the rise of high-voltage direct current (HVDC) technology, which makes longer and deeper cable installations possible.
As nations push toward cleaner, interconnected energy systems, high-voltage submarine cables are set to play a decisive role in shaping tomorrow’s power landscape.
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Technological Advancements
The technological evolution of submarine power cables is central to their expanding role in global energy systems. High-voltage submarine cables, defined as systems with a voltage rating above 33 kV, are widely used for integrating renewable energy into existing grids and extending transmission lines to single-generation points, such as offshore wind farms, oil and gas facilities, or inter-island networks.
These cables are designed for durability and efficiency. Most use copper or aluminum conductors with multiple insulation layers and are typically 3-core armored for mechanical strength and protection against harsh subsea conditions. A major leap has been the adoption of cross-linked polyethylene (XLPE) insulation, which offers higher current ratings and ensures longer transmission distances with reduced electrical losses. Combined with improved armoring techniques, XLPE-insulated, high-voltage cables ensure both reliability and efficiency in transmitting electricity across vast marine environments.
Innovations in HVDC technology have also helped submarine cables cover longer distances with minimal transmission loss. This capability is critical for interconnecting national grids and enabling cross-border electricity trading. On the market front, the global high-voltage-cable market size was valued at USD 19.57 billion in 2024 and is projected to increase from USD 20.79 billion in 2025 to USD 33.63 billion by 2033, growing at a compound annual growth rate (CAGR) of 6.2% during the forecast period (2025-2033). Additionally, the broader submarine cables market, including power and communications cables, is expected to reach USD 44.33 billion by 2030, growing at a CAGR of about 5.6% from 2025–2030.
As demand for renewable integration and secure interconnectors accelerates, these technological and market advances make high-voltage submarine cables indispensable infrastructure for the clean energy era.
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Key Global Projects and Investments
Europe is leading the development of HVDC submarine cables, prioritizing renewable integration, grid interconnectivity, and energy security.
- Italy: The Tyrrhenian Link’s western section is connecting Sicily and Sardinia with two 500 kV HVDC cables spanning 970 km and providing a 1,000 MW transmission capacity. The first 200 km segment is scheduled for completion in September 2025, while the second 280 km segment will be laid in December 2025. The total investment for this project is EUR 3.7 billion.
- Malta: The Malta–Italy Interconnector 2 covers a 100 km subsea route from Sicily to Malta. The project is managed by Nexans, with seabed surveys conducted by NextGeo, and is receiving EUR 165 million from the European Regional Development Fund 2021-2027.
- UK: NKT was selected as the preferred bidder for the Eastern Green Link 3 interconnector, which will provide a 525 kV HVDC cable system spanning 680 km to link Scotland and England, ensuring a reliable clean power supply.
- UK: LS Eco Advanced Cables (LSEAC) launched a five-week public consultation in May 2025 for a proposed USD 1.2-billion, high-voltage cable production facility at the Port of Tyne, designed to transmit offshore wind energy to UK shores.
- UK: JDR Cable Systems in the UK successfully completed 132 kV type tests for offshore wind array cables, supporting larger turbines, longer-distance transmission, and contributing to international safety standards and UK government floating offshore wind initiatives.
- Germany/Netherlands: TenneT contracted NKT in December 2024 to supply 525 kV HVDC onshore and offshore cables for two projects, LanWin7 and NordOstLink, with combined contracts valued at USD 1.03 billion.
- Sweden: NKT’s Karlskrona facility is expanding its production capacity with a third extrusion tower in partnership with ABB, enabling the production of offshore high-voltage cables up to 640 kV DC.
Asia is rapidly expanding HVDC manufacturing and subsea cable infrastructure to support offshore wind, regional grid interconnections, and high-capacity digital networks.
- South Korea: LS Cable & System completed the continent’s largest HVDC cable production facility in July 2025 and was selected as one of ten suppliers for the UK National Grid’s GBP 59-billion HVDC supply chain framework.
- Vietnam: The country is constructing its first extra-high-voltage cable manufacturing facility, which is intended to meet the region’s rapidly growing demand for advanced power transmission solutions and modernize the national grid.
- Japan/Taiwan/South Korea/US: The SoftBank-led E2A Consortium is building a 12,500-km, next-generation submarine cable system connecting Japan, Taiwan, South Korea, and the United States—with completion expected in the second half of 2028—to enhance digital connectivity and support high-capacity data transmission for AI and digital infrastructure.
North America is investing heavily in HVDC subsea cable manufacturing and transmission to support renewable energy integration and cross-border power delivery.
- US: LS GreenLink broke ground in April 2025 on the largest HVDC subsea cable factory, which is scheduled for completion in late 2027, with mass production expected to begin in early 2028.
- New York: Norway’s ABL was selected to provide marine warranty survey services for the Champlain Hudson Power Express (CHPE) project in New York, which is a 545-km HVDC transmission line delivering 1,250 MW of Canadian hydropower to the city.
- US: Oceantic has announced the construction of a 98-acre subsea cable manufacturing facility in the United States, expected to be operational by 2028, to produce next-generation HVDC cables for offshore wind projects.
- Canada: Hydro-Québec is advancing the New England Clean Energy Connect (NECEC) project, which involves a 1,200 MW HVDC transmission line designed to deliver renewable hydroelectric power from Quebec to the northeastern United States, strengthening cross-border energy trade and supporting regional decarbonization goals.
The Middle East is increasingly turning to HVDC submarine cables as a strategic tool to harness offshore energy resources, strengthen regional grid interconnections, and enable large-scale cross-border clean energy exports.
- Abu Dhabi: deugro delivered 700 km of subsea cable from Japan and Norway in July 2025 to support an HVDC submarine cable project led by Samsung C&T, highlighting complex logistics and coordination.
- Abu Dhabi: ADNOC is developing a 3,200 MW HVDC subsea transmission system that will connect offshore oil and gas production facilities to the onshore grid, replacing offshore gas turbines with electricity to reduce carbon emissions and improve operational efficiency, with commissioning scheduled for 2025.
- UAE–India: Plans are underway for a UAE–India HVDC interconnector, which is expected to have a capacity of 2,000–2,500 MW and enable large-scale transmission of clean energy from the UAE to India.
Future Outlook
The next decade will define the role of HVDC submarine cables, with interconnectors enabling bidirectional electricity flows, linking independent grids, and creating flexible, resilient energy markets. Successful deployment demands highly specialized expertise, from precision marine operations to advanced cable technology.
To be successful in the long run, collaboration between owners, developers, financiers, and insurers from the outset is essential. Transparent cooperation will further accelerate decision making and project delivery. Meanwhile, digital technologies will continue to transform subsea cables, making them resilient, smarter, and more dependable.
