Conceptual design of a floating support structure for an offshore vertical axis wind turbine: the lessons learnt

M. Collu, F. P. Brennan, M. H. Patel

Research output: Contribution to journalArticle

20 Citations (Scopus)
2 Downloads (Pure)


The design of floating support structures for wind turbines located offshore is a relatively new field. In contrast, the offshore oil and gas industry has been developing its technologies since the mid 1950s. However, the significantly and subtly different requirements of the offshore wind industry call for new methodologies. An Energy Technologies Institute (ETI) funded project called NOVA (for Novel Vertical Axis wind turbine) examined the feasibility of a large offshore vertical axis wind turbine in the 10-20 MW power range. The development of a case study for the NOVA project required a methodology to be developed to select the best configuration, based on the system dynamics. The design space has been investigated, ranking the possible options using a multi-criteria decision making (MCDM) method called TOPSIS. The best 'class' or design solution (based on water plane area stability) has been selected for a more detailed analysis. Two configurations are considered: a barge and a semi-submersible. The iterations to optimise and compare these two options are presented here, taking their dynamics and costs into account. The barge concept evolved to the 'triple doughnut-Miyagawa' concept, consisting of an annular cylindrical shape with an inner (to control the damping) and outer (to control added mass) bottom flat plates. The semi-submersible was optimised to obtain the best trade-off between dynamic behaviour and amount of material needed. The main conclusion is that the driving requirement is an acceptable response to wave action, not the ability to float or the ability to counteract the wind turbine overturning moment. A simple cost comparison is presented.

Original languageEnglish
Pages (from-to)3-21
Number of pages19
JournalShips and Offshore Structures
Issue number1
Early online date17 Jul 2012
Publication statusPublished - 1 Jan 2014


  • conceptual design
  • dynamics
  • floating support
  • offshore wind

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