Session: 09-01-16 Wind Energy: Structures 1

Paper Number: 124882

124882 - Nextfloat: Light Is Beautiful, Use of Lattice Structure in Floating Wind 

Since the Hywind Demo project, the first Floating Offshore Wind Turbine (FOWT) of 2.3 MW installed 12 km offshore Karmøy island, South West of Norway by Equinor in 2009, up to the ongoing Hywind Tampen floating wind farm composed of 11 units of 8.6 MW to provide electricity for the Snorre and Gullfaks oil and gas fields in the Norwegian North Sea, most of the FOWT deployed are spread moored to the seabed and use upwind 3 bladed turbines.

Some other small scale prototypes using catenary or tension legs, spread or single point moorings, single or multi-turbine configurations and upwind or downwind turbines were also tested during this period in a variety of environments.

The NextFloat project (European Commission Grant Agreement n°101084300 under Horizon Europe program) has started in November 2022. NextFloat will engineer and build an innovative weathervanning concept of FOWT that will be deployed and operate on the Mistral test site in the South of France near Marseille. The unit will be a 6 MW version of the PivotBuoy previously deployed by X1-Wind on the PLOCAN site in the Canary Islands.

This innovative platform concept specifically developed by X1-Wind for floating offshore environments in deep waters combines the advantages of a semi-submersible and TLP through its single-point mooring (SPM, called PivotBuoy®). The result is a downwind tripod-like platform that self-aligns passively with the wind allowing an efficient structural design eliminating also the traditional tower (which suffer high bending moments at its base and is very sensitive to 1P/3P excitations). Substantially lighter the downwind tripod structure is a more scalable design than the SPAR, semi or barge existing technologies. Furthermore, the use of lattice structure for the tripod legs allow a high weight saving of more than 1000 tons compared to the typical tower structure for the future 20MW+ turbines. Those benefits will be detailed in the publication including a comparison with tower solution.

Presenting Author: Marc Cahay Technip Energies

Presenting Author Biography: Marc CAHAY is Graduate Engineer in civil Engineering in 1990 from Ecole Spéciale des Travaux Publics (E.S.T.P.) in Paris, France. Member of the Technip Energies’s Experts network. He is coordinating the Offshore R&D activities since 2006 at Technip Energies in Paris, France, covering new technology, platform concept, installation system, floating offshore wind and solar. He has more than 30 years’ experience in fixed and floating structural design.

Authors:

Marc Cahay Technip Energies
Lucy Milde X1 Wind