Kincardine drops Windfloat for Cobra's SEMI-SPAR

In: FoundationsWindfarms

Developers of the Kincardine offshore wind farm project have submitted an addendum for the semi-spar foundations which will support the turbines at the site, located approximately 15km from the coast of Aberdeen, Northeast Scotland.

As the Project has progressed and design work has been carried out the project's developers, Kincardine Offshore Windfarm Ltd (KOWL), have decided to utilise Cobra’s SEMI-SPAR concrete substructure technology in preference to the Windfloat semi-submersible prototype which were presented in the original Environmental Statement (ES).

Cobra’s SEMI-SPAR foundation technology consists of a central column connected to three outer columns by rectangular pontoon sections, with the outer columns located below the water surface when operational. The wind turbine is mounted on the central column above the so called "transition cone". KOWL stated that the concept embraces the low-cost and constructability benefits of concrete with favourable spar motions during operations.

KOWl explained that the Cobra concept is easy to manufacture and assemble in port with no need for heavy lift crane capacity vessels, only conventional tug boats. The SEMI-SPAR concrete substructure technology is similar in design to the Windfloat concept described in the original ES and will require anchor points and mooring lines.

Due to the similarity of the technology, there is no change to the overall Rochdale Envelope as presented in the original ES, therefore no changes are required to the Environmental Impact Assessment methodology or conclusions presented in the original ES.

KOWL noted, however, that the switch in foundation does result in an increase of structure that is below the waterline, with a draft of 36m compared to the semi-submersible's 14m. The outer buoyancy chambers are now below the water surface, with the top of each being approximately 6m below the water surface. This new structure will allow support vessels to approach the structure and unload service engineers safely from all directions.

With a total of eight wind turbine generators, each 6MW, spaced less than 1km apart, the Kincardine project is expected to have a maximum installed capacity of 49.6MW. This could provided renewable energy for up-to 45,000 Scottish households.

The onshore transmission works, comprising of two 33kV export cables, will be subject to a separate application for Planning Permission under the Town and Country Planning (Scotland) Act 1997. The export cables, buried to depths up-to 1.5m, will bring power ashore to the existing Redmoss onshore substation, subject to a final agreement with the operator.

For more information about the Kincardine floating wind farm project please follow the links provided. Alternatively you can view the project on our interactive map.

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