Introduction
[BLUF] – The expansion of HVDC interconnections in Europe and Asia is occurring without shared technical standards for submarine cables. While projects such as the Tyrrhenian Link and SuedOstLink are achieving operational records, no international or national document explicitly covers test specifications for HVDC systems in marine environments, creating a critical regulatory gap that impacts network resilience.
The completion of the 2,150-meter deep Tyrrhenian Link on January 1, 2026 represents a documented operational limit, but it is not accompanied by standardized technical verification for extreme marine conditions. Submarine HVDC cables installed in Italy and Germany use proprietary technologies (P-Laser from Prysmian), without public declarations of compliance with IEC 62067:2022, which explicitly excludes submarine cables from standard applications.
Statements regarding the production capabilities of Hengtong Optic-Electric and Orient Cable lack verifiable data. There is no publicly available information on the operational availability of lines dedicated to XLPE HVDC cables in China, nor on whether systems comply with international standards for offshore applications (GB/T 31487).
The CLV market shows an increase in demand: Boskalis orders a ship with two carousels capable of carrying 12,000 tons; Dong Fang Offshore is building a new CLV to compensate for lost capacity in Taiwan following the incident involving the Orient Adventurer. However, the Energy-Solutions report estimates a global deficit of between 40 and 55 high-specification ships by 2028, without updated data on the actual capabilities of vehicles acquired by Taihan Cable & Solution.
In the HVDC sector, the approval of the SuedOstLink+ corridor in Germany does not resolve delays related to public acceptance. The German government reduced the priority for underground cabling on May 4, 2026, threatening €50 billion in investments between 1997 and 2026. Open sources do not indicate HVDC projects in BRICS+ countries financed by BRI or EIB.
The BRI 2025 report does not specify HVDC projects in group countries, nor are there data on EIB financing for projects in India or Pakistan. The Mumbai plant (1,000 MW) has declared funding as “not indicated.” The HVDC cable market is valued at $13.3 billion in 2025 and is expected to reach $15.49 billion in 2026.
The lack of regulatory coverage for submarine cables by both IEC and GB/T represents a critical point. We have no news of companies that have declared compliance with both sets of standards for offshore applications.
The most relevant fact is that, despite the progress of projects and the growth of the market, the certification system for HVDC submarine cables remains incomplete. The absence of shared standards for marine environments creates a structural risk to the resilience of expanding energy networks.
Productivity Capacity and HVDC Interconnection Project Announcements: 2025–2026
The completion of the 500 kV HVDC cable installation in the Tyrrhenian Link project, reaching a record depth of 2,150 meters on January 1, 2026, represents a technical milestone for European submarine infrastructure.
Productivity Capacity and Corporate Statements
Nexans confirmed its operational capacity through the completion of the Tyrrhenian Link, with 480 km of cables installed at a maximum documented depth. The company also signed a framework agreement with RTE to supply over 730 km total (450 km submarine and 280 km land) of HVDC cables, with a value exceeding €1 billion.
Prysmian announced a full order book until 2029 for offshore projects and unveiled the new 525 kV HVDC system with increased capacity from 2 GW to 2.5 GW. The €5.22 billion revenue in the first quarter of 2026 was attributed to its estimated global market share between 10% and 12% in HVDC submarine cables.
Hengtong Optic-Electric reported multi-billion dollar contracts for offshore projects in 2025, with a $2.5 billion investment in production equipment. However, no public data is available on the specific production capacity or dedicated XLPE HVDC cable production lines.
Orient Cable announced mass production of 2 GW HVDC systems in China and a strategic project linked to the PRC plan for the Morocco-England interconnection. No information was released about production capacities or operational availability of production lines.
Announced Interconnection Projects in 2025–2026
- Tyrrhenian Link (Italy): Completed on January 1, 2026, with 500 kV HVDC cables installed at a depth of 2,150 m; connects Sardinia and Sicily for a capacity of 1,000 MW.
- ELMED (Italy-Tunisia): Construction scheduled to begin in 2026, contract value €460 million, with production and installation by Prysmian through the Arco Felice factory in Naples.
- EGL4 (UK-Italy): Contract signed for €2.3 billion; connects Fife in Scotland to West Norfolk in England with a capacity of 2 GW.
- Western Isles and Spittal-Peterhead (Scotland): NKT received a €2 billion contract for 525 kV HVDC cables; projects under construction.
- SunZia (USA Southwest): Capacity of 3,000 MW, under construction with the involvement of Hitachi Energy and Quanta Services.
According to the IRENA benchmark from 2026, Chinese ±525 kV XLPE HVDC cables have a unit cost that is 22% lower than European ones. However, no public data is available on the technical specifications or compliance of Chinese products with European grid safety regulations.
The available evidence indicates that Nexans and Prysmian have consolidated their position in European HVDC projects with multi-billion dollar orders, while Hengtong and Orient Cable have expanded their footprint in China and strategic markets. However, statements about the production capacities of Asian companies are not accompanied by verifiable public data.
The most relevant piece of information is that the installation of the Tyrrhenian Link at 2,150 meters represents a documented operational technical limit, with direct implications for the resilience of energy interconnections in geologically complex areas.
Cable Laying Vessel (CLV) Deliveries and New Orders in the 2025–2026 Period: An Evolving Operational Overview
On May 18, 2026, Ulstein Verft delivered the Nexans Electra cable laying vessel to Nexans in Norway. The delivery was documented by multiple sources with consistent data on dimensions and total capacity.
CLV Deliveries in 2025–2026: Consolidated Evidence
- Nexans Electra: Delivered on May 18, 2026, by Ulstein Verft in Norway. Dimensions: 149.9 m long and 31 m wide.
- Fleeming Jenkin CLV: Launched on October 22, 2025, at Haimen (China) by Jan De Nul; delivery expected in the second half of 2026. Load capacity: 28,000 tons.
- Second Giant CLV from Jan De Nul: Launched on April 7, 2026, in Belgium, destined for offshore projects; technical details and delivery date are not available.
- Taihan Cable & Solution: Acquired a CLV from DOF Group on May 14, 2026. Technical specifications and vehicle capacity have not been publicly disclosed.
New Orders and Ongoing Projects: Active Shipyards
The data indicates an increase in demand for high-capacity CLVs, with announcements from strategic operators:
- Boskalis: Announced the order for a high-capacity CLV with two 12,000-ton carousels each; expected to be operational in 2029.
- Dong Fang Offshore: Signed a contract with the Norwegian shipyard Westcon for the construction of a CLV, delivery scheduled for the first quarter of 2027. The project is motivated by the loss of capacity in Taiwan due to DeepOcean’s exercise of the 2028 option for the Orient Adventurer, which will move the vessel to Europe by the end of 2028 with options until 2031.
- Ulstein Verft: Received the hull of the Nexans Electra on July 5, 2025, for final outfitting; hull launch occurred on November 13, 2025.
- Jan De Nul: Began construction of the sister ship to the Fleeming Jenkin in Haimen (China), indicating a significant commitment to European offshore projects.
Public Statements Regarding CLV Shortage
The Energy-Solutions report estimates a global deficit of between 40 and 55 high-specification CLVs by 2028. This estimate is based on market analysis and currently available installation capacities.
Operational Impact and Information Gaps
| Vessel | Shipyard | Delivery/Announcement Date | Total Capacity (tons) | Source |
|---|---|---|---|---|
| Nexans Electra | Ulstein Verft, Norway | May 2026 | 13,500 (on three turntables) | Ulstein Verft |
| Fleeming Jenkin CLV | Jan De Nul, Haimen (China) | Delivery expected 2nd half of 2026 | 28,000 | MarineLink |
| Boskalis CLV (order) | Unspecified shipyard | Announced 2026, operational in 2029 | 24,000 (two 12,000-ton carousels) | MarineLink |
The CEO of Dong Fang Offshore stated that the decision for the new CLV is motivated by the loss of installation capacity in Taiwan after DeepOcean exercised the 2028 option for the Orient Adventurer, which will move the vessel to Europe by the end of 2028 with options until 2031.
Dong Fang Offshore CEO, “The decision for the new CLV is motivated by the loss of installation capacity in Taiwan after DeepOcean exercised the 2028 option for the Orient Adventurer, which will move the vessel to Europe by the end of 2028 with options until 2031.”
For a more comprehensive assessment of the CLV market, updated data on the actual capacities of the vessels acquired by Taihan Cable & Solution and on the load capacity distribution of the Nexans Electra are needed; the company has announced the delivery.
The delivery of the Nexans Electra in May 2026 represents a key point in responding to the growing demand for offshore installation, while statements about the global shortage by 2028 indicate structural pressure on production and logistical capacities.
Divergences between IEC and GB/T standards for HVDC systems: operational implications and coverage gaps
The IEC 2067:2022 document, updated in its RLV version, specifies test methods for extruded high-voltage (HV) cables with insulation ranging from 150 kV to 500 kV nominal voltages, but explicitly excludes submarine cables from the standardized applications. According to the official text: “This International Standard does not apply to submarine cables.”
Documented technical differences between GB/T and IEC for HVDC systems
The GB/T 31487.1-2025, .2-2025, and .3-2025 standards define requirements for DC defrosting devices in HVDC systems, with national implementation scheduled for July 1, 2026. However, none of the three documents explicitly cover submarine cables.
The GB/T 31487.1-2025, which establishes design and testing requirements for DC defrosting systems, does not include marine applications. Similarly, the GB/T 31487.2-2025 focuses on water-cooled thyristor valves in HVDC plants but does not extend the tests to submarine cables.
Both IEC 62067:2022 and GB/T 18897 (submarine cables) have a functional correspondence with IEC 61851, but there is no publicly available data to confirm the adaptation of GB/T systems to international standards for offshore applications. The differences in converter testing between GB and IEC are documented as being related to specific local environmental conditions and compatibility with the Chinese grid.
Declared compliance by companies: gap between certification and standardization
Hengtong Group has obtained international certifications for its submarine products, including CE, BV, DNV, KEMA, ABS, UL, GL, ROHS, and TLC. However, the sources do not specify whether these certifications refer to IEC or GB/T standards for HVDC applications.
Shanghai Morn Electric Equipment Co., Ltd. manufactures 220 kV XLPE cables compliant with both IEC 62067 and GB/T 18890, with technical specifications such as a maximum operating temperature (90°C) and short-circuit resistance (≤250°C for 5 seconds). It is not indicated whether the cables are intended for offshore HVDC projects.
Sumitomo Electric completed the Korridor A-Nord: 525kV HVDC XLPE Cable Project in the second quarter of 2026, but no mention was made of the application of Chinese standards (GB/T) or compliance with IEC 62067 for the project.
Projects with HVDC applications: use of national and international standards
Hitachi Energy supplied HVDC plants for the Gansu-Zhejiang ±800 kV UHVDC project, designed by State Grid Corporation of China (SGCC). The largest VSC transformer ever built (750 MVA, ±800 kV) was produced for this project. No information is available on compliance with specific IEC 2067 or GB/T standards for submarine cables.
Prysmian has installed HVDC cables in the SuedOstLink in Germany (525 kV, >2 GW) and the Tyrrhenian Link in Italy (970 km submarine, 1.000 MW). The Italian project uses Prysmian’s P-Laser technology, but no mention is made of the use of Chinese standards.
The Champlain Hudson Power Express between the United States and Canada involves the installation of 400 kV HVDC cables with a planned start in 2026. No mention is made of any applicable GB/T or IEC standards for the components.
| Project | Voltage (kV) | Capacity (MW) | Referenced Standards | Not covered for submarine cables? |
|---|---|---|---|---|
| Gansu-Zhejiang ±800 kV UHVDC (China) | ±800 | 36 billion kWh/year | Not specified | Yes, if GB/T 31487.2-2025 or IEC 2067:2022 are applied |
| Tyrrhenian Link (Italy) | Not specified | 1,000 | P-Laser, no GB/IEC declared | Yes, for IEC 2067:2022 |
| SuedOstLink (Germany) | 525 | >2,000 | Not specified | Yes, for IEC 2067:2022 |
| Champlain Hudson Power Express (USA/Canada) | 400 | Not specified | Not specified | Yes, for IEC 2067:2022 |
Open sources do not contain information on companies that have declared compliance with both sets of standards (GB/T and IEC) for submarine HVDC applications. The company has reported international certifications, but has not published specific documentation on cable testing under marine conditions.
For a more complete assessment of regulatory compliance in offshore projects, data would be needed on: (1) the exact version of the GB/T document applied to the components; (2) the list of tests performed according to IEC 2067:2022 or GB/T 31487.2-2025; (3) technical audit documentation for HVDC submarine cables.
The lack of coverage of submarine cables by both IEC and GB/T standards, despite the increasing use in offshore projects, represents a critical point for the resilience of high-voltage transmission infrastructure.
Regulatory Delays and Strategic Choices in the HVDC Sector in Europe: An Updated Overview as of June 2026
The delay in implementing the HVDC infrastructure has significantly impacted offshore projects in Germany, with TotalEnergies reporting risks to investments totaling €50 billion between 2021 and 2026. The critical factor is the complexity in defining high-voltage direct current (HVDC) transmission routes, particularly for underground corridors.
Approval of the SuedOstLink+ Corridor and Strategic Shift on Underground Cabling
The German Federal Network Agency (BNetzA) approved the route of the HVDC SuedOstLink+ corridor in Germany on June 1, 2025, with a width of 1,000 meters. This decision represents a formal step in the permitting process, but does not resolve delays related to public acceptance.
On May 4, 2026, the German government announced a reduction in priority for underground HVDC lines. According to open-source information, this shift “threatens investment security and will once again lead to substantial delays due to the lack of public acceptance of future lines.”
Offshore Projects at an Advanced Stage: Key Assignments and Contracts
On June 2026, 50Hertz awarded a contract for a 2 GW offshore conversion platform in the North Sea Connector 2 to Siemens Energy and NSORe. This represents the first large-scale construction in Germany for HVDC offshore projects.
Other key developments include:
- Taihan Cable: signed collaboration agreements with Jan De Nul and Boskalis on June 11, 2026, for the underwater HVDC sector.
- PALFINGER: received a contract to supply cranes for HVDC platform installations in the North Sea on May 20, 2026.
- COSCO: completed the installation of a 2 GW conversion platform for the Qingzhou V & VII project in China on June 10, 2026.
Projects in India: Network Expansion and Installed Capacity
On April 2026, Hitachi Energy and Adani commissioned an HVDC plant in Mumbai with a capacity of 1,000 MW, 50 km of underground cables, and a 50% increase in power supply to the city.
India has planned an HVDC ‘Super-Grid’ to transmit up to 1,800 GW of renewable energy from Rajasthan and Gujarat to industrial regions, with unspecified investments. The project is in the strategic definition phase.
HVDC Market Overview: Financial Dynamics
The HVDC cable market was valued at $13.3 billion in 2025 and is expected to reach $15.49 billion in 2026, with a CAGR of 18.7% until 2036. This growth is supported by offshore projects in Europe and the expansion of renewable energy networks in India.
“The reduction in priority for underground cabling threatens investment security and will once again lead to substantial delays due to the lack of public acceptance of future lines.”
— Source: Europacable.eu, May 4, 2026
Operational Impact and Risks to Infrastructure Resilience
The power outage in Pakistan on June 17, 2026, caused by a faulty transformer, affected 13 regions and 18 distribution stations for 6 hours. This event highlights the vulnerability of existing networks, even beyond the HVDC projects under development.
The most relevant point is that, despite the formal approval of the SuedOstLink+ corridor and progress on key contracts for offshore projects in Germany, the failure to resolve regulatory issues and public acceptance directly impacts the resilience of infrastructure and investment security in the HVDC sector.
Photo by boris misevic on Unsplash
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