Technology
Beyond roughly sixty metres of water a fixed foundation stops being economic, which rules out most of the world's offshore wind resource. A floating platform trades the problem of driving steel into the seabed for the problem of holding a moving structure steady — and moves most of the assembly work back onto the quay.
In one sentence
A floating wind substructure is a buoyant platform — semi-submersible, spar or tension-leg — that carries a turbine in deep water, held on station by a mooring system anchored to the seabed and connected by a dynamic cable that flexes with the platform's motion.
Three families dominate. A semi-submersible floats on widely spaced columns, has a shallow enough draught to be assembled at a quay and towed out, and is what most demonstration projects have used. A spar is a long ballasted cylinder, very stable but requiring deep sheltered water to upend and fit the turbine. A tension-leg platform is held down by taut vertical tendons, moves least of the three and is the hardest to install.
The industry is structured differently from fixed foundations. Platform designs are largely licensed by engineering firms and built by yards under contract, rather than sold as a product by one manufacturer, and cost per megawatt is still a multiple of fixed-bottom. The open questions are serial fabrication, ports able to assemble the units, mooring and dynamic cable supply, and whether maintenance means towing a turbine back to port.
A turbine on a moving base can drive itself unstable: the controller reacts to the platform's pitch, and the correction feeds the motion rather than damping it. Floating designs therefore need a control strategy written for the platform, and the drivetrain has to be qualified for nacelle accelerations a fixed machine never sees. This is why turbines are certified for floating use rather than simply mounted on a float.
A platform is held by catenary chain or taut synthetic lines running to drag-embedment, suction or driven anchors, and the mooring spread claims a seabed footprint many times the platform. Heavy offshore chain comes from a handful of mills, and a commercial-scale build-out needs more of it in a year than the mooring industry has previously made.
Power leaves a floating turbine through a cable suspended in the water column, bending with every wave for the life of the project. It is a different qualification problem from static subsea cable — fatigue of the conductor and the armour rather than electrical ageing alone — and it is the component most often named when operators discuss floating reliability risk.
Platforms are assembled lying at a quay, with the turbine fitted before tow-out. That needs load-bearing quay area measured in hectares, deep enough water to float out a loaded structure, and no bridge between the port and open sea. Very few ports qualify, and upgrading one is a public infrastructure decision rather than a supplier's.
3 of these are marked as a chokepoint: a handful of qualified suppliers, a multi-year lead time, or a single geography.
A suspended cable that flexes for decades is qualified separately from static subsea cable and is made by fewer suppliers.
High-voltage cableThe nacelle must tolerate accelerations and the controller must not amplify platform pitch, so the machine is certified for the platform rather than sold independently of it.
Nacelles and drivetrainsPlatforms are towed to site and moorings are pre-laid by anchor handlers, drawing on the same constrained offshore fleet.
Installation vesselsHeavy offshore chain is made by a handful of mills, and commercial-scale floating would need step-change volumes of it.
Quayside assembly requires load-bearing area, draught and an unobstructed route to sea, which almost no existing port has.
What each company supplies at this step, and — where a public figure exists — its share of this specific market — with what that share measures, the period it covers and who published it. Some rows also show the company’s own reported revenue for the segment covering this step, which is a different thing: it says how much this business matters to that company, not how much of the market it holds. Not a ranking and not a recommendation.
Licenses the semi-submersible platform used by several of the first floating projects.
Licenses a damping-pool platform built in concrete or steel, and co-develops projects using it.
Engineers and fabricates floating substructures and their mooring systems.
Designs a floating platform and installs moorings and cables with its offshore construction fleet.
Develops floating substructure designs and the engineering for their fabrication.
Owns the spar design behind the first floating wind farms and most of the operating experience with them.
Builds floating platforms and the turbines mounted on them, including twin-rotor designs.
Whether the first commercial-scale floating leases convert into construction contracts.
Whether serial fabrication brings platform cost within sight of fixed-bottom.
Whether dynamic cable and mooring qualification keeps pace with platform designs.
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