Why Nexans’ high-voltage export cables matter for the next offshore wind wave

Reviewed: ad hoc news B2B & Pro desk. Edited and checked on 2026-06-20, 05:13. Details in the imprint.

Nexans high-voltage submarine export cable is one of those products you never see on a shop shelf, yet it decides whether a whole offshore wind farm quietly does its job or suddenly goes dark on a stormy winter evening.

What this cable actually does

At its core, the Nexans high-voltage submarine export cable is the power highway between offshore turbines and the onshore grid. It bundles hundreds of megawatts from a wind farm and pushes them through copper or aluminum conductors over tens or even hundreds of kilometers under water.

The outer diameter easily reaches the thickness of a strong human forearm. Under the black sheath hide layers for mechanical protection, water blocking and insulation, all designed so that salt water, currents, fishing gear and anchors do not kill the power flow for decades.

Inside the arm-thick structure

Technically, we are talking about a high-voltage alternating current or direct current cable, depending on project size and distance. The insulation is typically cross-linked polyethylene, XLPE in short, a material that can handle high electrical stress and remains stable under thermal load.

A metallic screen and armoring wires surround the insulated core. They give the cable the mechanical strength to survive installation from a heavy vessel and later live on the seabed, where currents constantly pull and push on the line.

Designed for rough offshore reality

On deck of a cable-laying vessel, the Nexans high-voltage submarine export cable lies coiled in huge carousels, sometimes thousands of tons in one continuous length. During installation it slowly slides over a chute into the sea, the steel armor groaning under tension.

Once on the seabed, ploughs or remotely operated vehicles bury the cable into the sediment, often one to two meters deep. The goal is simple and uncompromising: keep it away from anchors, trawl nets and ice scouring as much as possible.

Why offshore operators care

For a wind-farm owner, this cable is both lifeline and single point of failure. A defect in the export path can take an entire gigawatt-scale park off the grid, even if every single turbine still spins happily in the wind.

Repair campaigns offshore are slow and expensive. A specialized vessel needs to be chartered, weather windows must fit, and every day of outage means lost revenue, which is why reliability and proven design top the shopping list.

How Nexans positions the product

Nexans has been active for years in high-voltage submarine projects across Europe and beyond, and markets its export cables as part of turnkey packages. The group does not only supply the cable itself, but also engineering, accessories and installation services for complex wind-farm connections.

This vertical setup means the same company plans how much power needs to flow, designs the cable cross-section and later lays it on the seabed. For operators, that can reduce interface risks, because there is one partner accountable for the whole link.

Technical choices that matter on paper

From a planning perspective, conductor material and size are crucial. Copper offers lower electrical resistance than aluminum, but is heavier and more expensive. Aluminum is lighter and cheaper, which helps when extremely long routes or shallow water constraints limit how much weight a vessel can safely carry.

Engineers also play with operating temperature. Higher permissible conductor temperatures allow more current through the same cable, but they stress materials and seabed thermals more. Nexans, like rivals, therefore specifies continuous ratings that try to balance capacity and lifetime.

How it feels in day-to-day operation

In daily grid operation, the beauty of a well-designed export cable lies in its silence. Control rooms see only power flows and line temperatures on screens, no drama. The cable itself rests in the dark, cooled by cold seawater and slowly shifting sand.

Only during storms and peak output days does the system really break sweat. Then, high currents heat the conductor, and thermal models decide how much longer the operator can push before needing to curtail generation to protect the asset.

Where the limits show up

There are also practical annoyances. Every landfall requires carefully engineered joints between the submarine export cable and transition joints onshore. These joints are bulky, expensive and demand precision work, as any partial discharge or moisture ingress can eventually lead to failure.

In very shallow or busy coastal waters, routing becomes a tedious compromise. Environmental constraints, shipping lanes and fishing zones leave limited corridors, where every meter of cable must be positioned so that it neither disturbs habitats nor suffers mechanical abuse.

Offshore wind is getting bigger

The trend in offshore wind clearly goes to larger farms further out at sea. That pushes export cables to higher voltage classes and longer continuous lengths, because every additional offshore substation adds complexity and cost that developers would rather avoid.

Nexans’ high-voltage submarine export cable family therefore targets voltage levels that fit modern offshore substations and converter platforms, aligning with the industry move toward higher capacity connections and long-distance links to strong onshore nodes.

Competition and differentiation

Nexans plays in a tough field alongside other European and Asian cable makers. Differentiation often comes down to project track record, execution capability and the ability to mobilize vessels and engineering teams quickly for tight offshore construction windows.

For developers, the question is less who has the prettiest catalog and more who has proven they can deliver a fully functioning export link on time, with acceptable risk of defects over a twenty- or thirty-year lifetime.

Why investors still look at this niche

Even if it is a B2B niche, high-voltage submarine export cables tie directly into the broader electrification story. Every offshore tender that closes, every grid strengthening plan that includes sea crossings, potentially feeds into the order book of suppliers like Nexans.

For long-term oriented investors, the boring, heavy copper-and-polymer products transforming seabed routes into power highways are a tangible way to gauge how serious the energy transition has become beyond press releases and politics.

Company context and trading reference

Nexans, headquartered in France, has built its strategy around what it calls electrification value chains, with high-voltage subsea and land cables forming a core business cluster alongside building, mobility and data solutions. Shares of Nexans S.A. (FR0000044448) trade on Euronext Paris in euros.

This article was AI-assisted and editorially reviewed. Product information without guarantee; prices and availability may change at short notice. No investment advice, no buy or sell recommendation. Stock-market transactions involve risks up to total loss.

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