Underground, submarine and superconducting cables: Value chain
A handful of cable makers with order books years deep
What this tab covers Who does what, from equipment makers to builders, owners, operators, traders and users, with the leading companies at each step.A small group of specialist cable makers, a handful of installation contractors with laying ships, and grid operators who own the links make up the chain. National Grid's 2025 HVDC framework admitted only six cable suppliers, which shows how concentrated the top tier is.
The chain
Cable makers Installers and laying ships Owners and operators Risk, insurance and certification Regulators and governments| Stage | What happens | Leading companies |
|---|---|---|
| Cable makers | Make the conductor, insulation and armour in long continuous lengths at coastal factories and test them. National Grid's 2025 HVDC cable framework lists six suppliers, including these five. | Prysmian (Italy) NKT (Denmark) Sumitomo Electric (Japan) LS Cable and System (South Korea) Hellenic Cables, part of Cenergy Holdings (Greece)192324 |
| Installers and laying ships | Plan the route, survey the seabed, lay and bury the cable, and repair faults. | Jan De Nul (Belgium) Prysmian (Italy) NKT (Denmark) LS Marine Solution (South Korea)4202127 |
| Owners and operators | Transmission system operators and interconnector developers own the cables, sell capacity and run them. | National Grid (UK) Energinet (Denmark) Elering (Estonia) TenneT and TransnetBW (Germany, SuedLink)451316 |
| Risk, insurance and certification | Assess cable failure risk for insurers and lenders. | DNV (Norway)6 |
| Regulators and governments | Approve routes, set rules for underground versus overhead lines, and set allowed returns. | Bundesnetzagentur (Germany) European Commission (EU)1112 |
Order books show the concentration: NKT ended 2025 with a high-voltage backlog of about EUR 10.2 billion, after EUR 10.8 billion at the end of 2023, when about half was for interconnectors and 45% for offshore wind and about 75% of that year's orders came from large European grid operators. NKT and Prysmian share Germany's SuedLink cable contracts, and NKT has an investment programme of about EUR 1 billion that includes expanding its Karlskrona plant in Sweden.
Buyers increasingly lock in supply years ahead through framework deals. National Grid's HVDC supply chain framework (2025) runs for five years with an option for three more, with about £21.3 billion for cables and £24.6 billion for converters; the Jan De Nul and Hellenic Cables consortium is one of six cable suppliers.
Sources
- National Grid announces commercial operations of Viking Link National Grid, 2023
- Laying of world record power cable between the UK and Denmark now complete National Grid Ventures, 2023
- 80% of insurance claims in offshore wind are related to subsea cable failures DNV, 2024
- Germany plans switch from underground to overhead power lines to cut costs: report Clean Energy Wire, 2026
- Drones, spare parts and sanctions: EU unveils action plan for submarine cable security Eunews, 2025
- Smooth repair work brings EstLink 2 connection back to market already on Friday Elering, 2025
- Germany starts construction on two more stages for 4 GW SuedLink HVDC cable S&P Global Commodity Insights, 2025
- Offshore wind accounts for 45 pct of NKT's high-voltage order backlog offshoreWIND.biz, 2024
- National Grid Framework Agreement Jan De Nul, 2025
- Construction of 'Asia's Largest HVDC Cable Facility' Wraps Up offshoreWIND.biz, 2025
- National Grid awards HVDC supply chain framework contracts National Grid, 2025
- NKT A/S Annual Report 2025: 6% organic growth and record-high operational EBITDA NKT, 2026
- LS C&S quadruples HVDC cable capacity through addition of cable production plant Wire Association International (WAI), 2025