Submarine HVDC cables rank among the most capital-intensive assets in global energy infrastructure, with installation costs running €2–5 million per kilometer plus hundreds of millions for converter stations. These undersea links are critical for offshore wind integration and cross-border interconnectors, but their price tags often exceed €2–3 billion per project. For investors, the growth opportunity lies with cable makers like Prysmian, Nexans, and NKT, whose orderbooks benefit directly from rising demand despite supply-chain and cost challenges.
Quick Summary
- Typical HVDC submarine cable cost: €2–5m per km in 2025.
- Converter stations add €300–600m each to project budgets.
- A 500 km, 1 GW subsea interconnector often exceeds €2–3bn total cost.
- Listed cable makers: Prysmian (BIT: PRY), Nexans (EPA: NEX), NKT (CPH: NKT).
- Costs vary by depth, seabed geology, protection, and installation logistics.
Why Submarine HVDC Cables Are Expensive
Submarine HVDC cables are among the most complex infrastructure assets in energy transmission:
- Built with copper/aluminium conductors, XLPE insulation, and steel reinforcement.
- Require specialized vessels for laying, jointing, and burial.
- Operate in deep-sea and high-pressure environments with reliability critical for grid stability.
Cost Breakdown (2025 Estimates)
| Component | Typical Cost Range | Notes |
|---|---|---|
| Submarine HVDC cable | €2–5m per km | Driven by depth, terrain, copper price |
| Converter station (per terminal) | €300–600m | Needed at each end for AC/DC conversion |
| Installation & logistics | 20–30% of cable cost | Specialized vessels, marine surveys |
| O&M (lifetime, 30 yrs) | ~2–3% of capex p.a. | Routine inspections, repair reserves |
Example: A 500 km subsea HVDC link at €3.5m/km → €1.75bn for cable + €600–1,200m for converters → €2.3–3.0bn total.
Factors Influencing HVDC Cable Cost
- Seabed conditions: Rocky seabeds require trenching or protection, increasing costs.
- Water depth: Ultra-deep installations (>1,000 m) add technical complexity.
- Power capacity: Higher MW rating requires thicker conductors and insulation.
- Material prices: Copper and aluminium volatility directly affect costs.
- Project scale: Larger multi-terminal projects achieve some economies of scale.
Investor-Relevant Companies
Prysmian (BIT: PRY)
- Largest global subsea HVDC cable manufacturer.
- Premium margins supported by scarce vessel and production capacity.
Nexans (EPA: NEX)
- Strong European presence, active in NordLink, Greenlink, IFA2.
- Smaller scale than Prysmian but competitive in tenders.
NKT (CPH: NKT)
- Focused on European HVDC and offshore wind interconnectors.
- Mid-cap with high operating leverage to order wins.
FAQ
Q: How much does an HVDC submarine cable cost per km in 2025?
Costs typically range between €2–5 million per km, depending on depth, terrain, and capacity.
Q: What is the total cost of a 500 km HVDC interconnector?
Including cables and converter stations, a 500 km, 1 GW link usually costs €2–3 billion.
Q: Which companies make HVDC submarine cables?
Prysmian, Nexans, and NKT are the main listed players.
Q: Why are submarine HVDC cables so expensive?
They require advanced materials, specialized vessels, and must operate with near-perfect reliability under harsh ocean conditions.