Function

The offshore substation foundation supports the topside structure.

What it costs

About £12 million for a 450 MW floating offshore wind farm, using a jacket foundation for an HVAC offshore substation.

Who supplies them

Bladt, Chantiers De l’Atlantique, Hollandia, HSM Offshore, Lamprell, Navantia, Sembcorp Marine and Smulders.

Offshore substation jackets.
Offshore substation jackets. Image courtesy of Orsted. All rights reserved.

Key facts

Offshore substations can either be supported by fixed foundations or floating substructures. Fixed offshore substation foundations are likely to be jackets. These are steel lattice structures with usually three or four legs that are anchored to the sea bed using pin piles or suction buckets. Floating offshore substations can use any of the same substructure types available to support turbines, that is barge, semi-submersible, spar, or TLP (see B.2 for further information).

Floating offshore substations are yet to be commercially proven. For this reason, we expect early floating offshore wind farms to use offshore substations with fixed jacket foundations. We expect floating offshore substations to be adopted once the technology is proven.

What’s in it

Guide to a Floating Offshore Wind Farm