It is not clear if copyright permissions have been obtained for these figures. The paper has presented many interesting figures.For example, given the day rates of vessels and existing procedures of marine operations, is it possible to compare the installation costs of spar, semi-submersible floating wind turbines? Many relevant papers have been properly reviewed, but it would be better if the authors can do some quantitative studies to show the cost components of marine operations with clarified assumptions. To the reviewer, the discussion of cost modelling of floating wind turbine marine operation is particularly interesting. The motivation for this paper should be further strengthened, given a few existing review papers on similar topics.It is recommended to revise the title to better reflect the content. However, the title appears to be over-ambitious, as the paper only addresses these topics incompletely. The title of the paper covers a broad range of interesting subtopics including installation, operation, maintenance, and decommissioning.There are a few concerns that should be addressed. The paper is well-written and easy to follow. This paper presents an interesting review of the challenges and opportunities of floating offshore wind turbines.

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