The comments are attached as a PDF file.

This paper provides recent, detailed field data on the reliability of modern onshore and offshore wind turbine systems. The data and analysis help to advance understanding of failure rates and development of maintenance strategies. The paper could be improved by providing greater detail to describe the population of turbines in the dataset (without breaching confidentiality requirements). Specifically, it would be valuable to include figures or tables that show the distribution of rated capacities among onshore and offshore turbines, the distribution of turbine ages (operational years), and the shares of technology type such as geared/direct drive/hybrid.

In the presentation of results, please provide more discussion of the difference between failure rates per MW and per WT. Comparison of Figs. 1 & 2 would seem to indicate that for some components (e.g. MDA, MDY) the failure rate is relatively constant per WT whereas other components (e.g. MDL, MDX) appear to have a constant rate per MW. It would also be helpful to note the average rating of onshore and offshore WTs.

The comparison of failure rates across OEMs does not add much value because the OEMs must remain anonymous. A comparison across characteristics that could be identified (such as drivetrain concepts or generator types) would have more value to researchers interested in using this paper to identify areas for future study or application of new maintenance strategies.

The comparison of results for onshore WTs with previous studies would benefit from more explanation of the differences between turbine populations, for example, normalizing by rated power as you have done for offshore WTs.

Please define major component replacement in the context of this paper. Do you use a size or cost threshold to identify MCRs?

Table 2 is unnecessary, the contents are already present in the preceding paragraph.