Hywind Tampen is described as the world's largest floating wind farm, and the label is accurate as far as it goes — but "floating" undersells what actually keeps it in place. Eleven turbines sit atop spar-buoy hulls in 260–300m of North Sea water, and the entire foundation system is built to resist movement, not to bob with it.

Developed by Equinor roughly 140km off the Norwegian coast, the project exists because the water is too deep for a fixed monopile — the standard foundation for shallower offshore wind. A floating hull was the only option. What makes Hywind Tampen notable is how deliberately its designers engineered that hull to behave like a fixed structure anyway.

11
SG 8.0-167 turbines
94.6 MW
Installed turbine capacity
107 m
Spar hull height
260–300 m
Water depth
Stage 1
The hull itself
Each turbine sits on a cylindrical spar-buoy hull roughly 107m tall — a concrete lower section 66m long and 18m in diameter, tapering to an 8m-diameter steel upper section. The concrete mass sits low and deep, well below the wave zone, doing the opposite job of a boat hull: keeping the structure down and stable rather than buoyant and responsive.
Stage 2
Mooring as the primary stability system
Each hull is held on-station by a mooring system anchored to the seabed. The balance between mooring-line tension and the hull's sub-surface ballast is what keeps pitch, roll and heave within tolerance — the mooring isn't just holding position, it's actively suppressing the motion a floating structure would otherwise be free to make.
Stage 3
Cabling and array configuration
The 11 turbines are connected by a loop of dynamic inter-array cables, each 2.5km long — cabling engineered to flex with the platforms' limited motion rather than resist it outright, since some movement at the hull level is unavoidable even with a well-tuned mooring system.
Purpose note

Unlike most offshore wind farms, Hywind Tampen doesn't feed the public grid directly. It supplies electricity to Equinor's Snorre and Gullfaks offshore oil and gas platforms nearby, cutting their emissions — making it the first floating wind farm built specifically to power existing offshore installations rather than the shore-based grid.

The world's largest floating wind farm was engineered to avoid floating — mooring tension and sub-surface ballast do the work that buoyancy alone never could.

Hywind Tampen was Equinor's first power in November 2022, fully installed by May 2023, and officially opened that August. It held the title of world's largest floating wind farm at commissioning; several larger floating projects are in development for the late 2020s, so that specific claim is worth checking against current data rather than treating it as fixed. What won't change is the underlying engineering logic: in water too deep for a monopile, the floating hull isn't the solution on its own — the mooring and ballast system built around it is.

For further reading, see Heavy Lift Engineering for Offshore Wind, which places floating foundation methods in a wider sector context.