Technical Definition of the TetraSpar Demonstrator Floating Wind Turbine Foundation

Borg, Michael; Jensen, Morten Walkusch; Urquhart, Scott; Andersen, Morten Thøtt; Thomsen, Jonas Bjerg; Stiesdal, Henrik

doi:10.3390/en13184911

Cited by 44 publications

(34 citation statements)

References 1 publication

(1 reference statement)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A prototype of the TetraSpar floater design aims to reduce production and installation costs of floating offshore wind turbines by utilising simple tubular elements and by use of the counterweight. This counterweight can be lowered once the turbine has been towed to the deployment site, thus eliminating the need for deep-water harbours and/or the use of expensive offshore operations vessels (see Borg et al (2020) for details of the full-scale deployment, with the floater installed in July 2021). The wave basin is 30m wide and 20m long, with an absorbing beach and an articulated flap wavemaker hinged 1.5 m above the basin floor (see figure 1).…”

Section: Basin Experimentsmentioning

confidence: 99%

Wave- and drag-driven subharmonic responses of a floating wind turbine

et al. 2021

View full text Add to dashboard Cite

The nonlinear hydrodynamic responses of a novel spar-type soft-moored floating offshore wind turbine are investigated via analysis of motion measurements from a wave-basin campaign. A prototype of the TetraSpar floater, supporting a $1:60$ scale model of the DTU 10 MW reference wind turbine, was subjected to irregular wave forcing (with no wind) and shown to exhibit subharmonic resonant motions, which greatly exceeded the wave-frequency motions. These slow-drift responses are excited nonlinearly, since the rigid-body natural frequencies of the system lie below the incident-wave frequency range. Pitch motion is examined in detail, allowing for identification of different hydrodynamic forcing mechanisms. The resonant response is found to contain odd-harmonic components, in addition to the even harmonics expected a priori and excited by second-order difference-frequency hydrodynamic interactions. Data analysis utilising harmonic separation and signal conditioning suggests that Morison drag excitation or third-order subharmonic potential flow forcing could be at play. In the extreme survival-conditions sea state, the odd resonant responses are identified to be drag-driven. Their importance for the tested floater is appreciable, as their magnitude is comparable to the second-order potential flow effects. Under such severe conditions, the turbine would not be operating, and as such neglecting aerodynamic forcing and motion damping is likely to be reasonable. Additionally, other possible drivers of the resonant pitch response are explored. Both Mathieu-type parametric excitation and wavemaker-driven second-order error waves are found to have negligible influence. However, we note slight contamination of the measurements arising from wave-basin sloshing.

show abstract

Section: Basin Experimentsmentioning

confidence: 99%

Wave- and drag-driven subharmonic responses of a floating wind turbine

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Section 3 presents, compares and discusses the results and is followed by the concluding remarks. A more detailed description of the TetraSpar and its structure can be found in [10].…”

Section: Keelmentioning

confidence: 99%

“…In order for the FOWT technology to reach a fully commercial and economically feasible stage, it is a strategical approach to ensure a design which is ready for a scalable and industrialized production, which minimizes required work at the port of embarkation and which eliminates the need for specialized vessels [10].…”

Section: Introductionmentioning

confidence: 99%

“…The TetraSpar FOWT foundation, as seen in Figure 1, has been designed based on these criteria, solely relying on components that are highly industrialized and suitable for mass production, with an already existing supply chain. The production takes place at factories and the structure is assembled at ports by an already available workforce [10]. A TetraSpar 3.6 MW demonstrator has presently been manufactured and assembled in Denmark, ready for deployment and with expected installation at the Norwegian coast during 2021 [10,11].…”

Section: Introductionmentioning

confidence: 99%

“…The production takes place at factories and the structure is assembled at ports by an already available workforce [10]. A TetraSpar 3.6 MW demonstrator has presently been manufactured and assembled in Denmark, ready for deployment and with expected installation at the Norwegian coast during 2021 [10,11]. In addition to the apparent criteria needed for securing commercialization, the floating foundation naturally needs to provide sufficient static and dynamic stability.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Comparative Investigation of Prevalent Hydrodynamic Modelling Approaches for Floating Offshore Wind Turbine Foundations: A TetraSpar Case Study

Thomsen

Têtu

Stiesdal³

2021

JMSE

Self Cite

View full text Add to dashboard Cite

Numerical models have been used extensively in the design process of the TetraSpar floating offshore wind turbine (FOWT) foundation to optimize and investigate the influence from a number of structural and environmental conditions. In traditional offshore design, either the Morison approach or a linear boundary element method (BEM) is applied to investigate the hydrodynamic loads on a structure. The present study investigated and compared these two methods and evaluated their applicability on the TetraSpar FOWT concept. Furthermore, a hybrid model containing load contributions from both approaches was evaluated. This study focuses on motion response. In the evaluation, hydrodynamic data from BEM codes are applied, while the commercial software package OrcaFlex is utilized for time series simulations of the coupled structure. The investigation highlights the difference between the modelling approaches and the importance of particularly drag and inertia contributions. By optimizing the input coefficients, reasonable agreement between the models can be achieved.

show abstract

Evaluating technical and financial factors for commercialising floating offshore wind: A stakeholder analysis

Smith

Clayton²,

Weijde

et al. 2022

Wind Energy

View full text Add to dashboard Cite

Recently, floating wind has enjoyed much public and governmental attention and is commonly identified as a crucial next step on the route to net zero targets for many countries. However, there is currently a large gap between the scale and readinesslevel of devices in the water and the end-of-the-decade aspirational targets of many governments. To facilitate the expansion of the industry, a wider acceptance and agreement of the realistic potential of floating wind and the barriers to the sector's development is required, particularly over this crucial 10-year period, something currently scarce in published literature. In this work, a stakeholder engagement was performed, with subsequent analysis of the results to quantify industry expectations and identify the predominant technical and financial concerns of key stakeholders.The presented results of the work serve to both provide a point of comparison and updated account of industry-based expert views in the near term, with further scientific analysis investigating distinctions between different stakeholder types.Secondarily, the key concerns of industry were analysed and compared with a literature review of recent research effort within floating wind, providing a high-level gap analysis. A knowledge of the gaps can inform future areas for academic enquiry, ensuring the future needs of industry and the focus of research is aligned.

show abstract

Technical Definition of the TetraSpar Demonstrator Floating Wind Turbine Foundation

Cited by 44 publications

References 1 publication

Wave- and drag-driven subharmonic responses of a floating wind turbine

Wave- and drag-driven subharmonic responses of a floating wind turbine

A Comparative Investigation of Prevalent Hydrodynamic Modelling Approaches for Floating Offshore Wind Turbine Foundations: A TetraSpar Case Study

Evaluating technical and financial factors for commercialising floating offshore wind: A stakeholder analysis

Contact Info

Product

Resources

About