Dear Mingming Zhang,

I recommend the article to be accepted, with minor revisions. As the authors mention, there is currently a lack of scientific articles addressing microplastic emissions from wind turbine blades.  I believe the current manuscript provides the best estimate of microplastic emissions due to leading edge erosion there currently is. 

First, some very minor details:

• I would add in the abstract that the estimate of 240 g per turbine is for a 15 MW turbine. 
• In Table 1, I would prefer it if it was indicated that the Solberg et al., (2021) estimate is based on errors. It is mentioned in the main text, but it is worth repeating in case readers copy the table.  
• In the SI excel file, the word "length" is misspelled. 

Some larger points to further improve the manuscript:

A comment on the structure of the methods and results section:

Throughout the methods and results section, calculation methods and their results are interwoven. I was a bit lost when reading the methods section, as some important information on the calculation methods are not discussed until the results section. It would be better to either present methods and assumption separately, or to change the main headings to better represent that the text in chapter 3 includes both methods and results. 

I think the discussion could be more in depth, some points:

Line 298 - 301 "Our estimate of 240 grams per turbine per year is on the lower end of the existing range of available estimations (see Table 1),

which spans from 3 grams to 14 kilograms per turbine per year (excluding the erroneous estimate by Solberg et al. (2021)).. At

240 grams, our estimate is rather close to the 150-gram estimate provided by Vestas (NORWEA, 2021). The aforementioned

lack of information on the estimate in the literature prevents us from further investigating the reasons for the differences"

It is worth mentioning that the upper estimate of 14 kg is also a deliberate overestimation by the original authors, which assumed the entire length of the blade eroded (instead of the more realistic 25% in this study). Furthermore, some of the estimates are for blades without leading edge protection. I agree that comparison to results of other sources is otherwise difficult, but the authors could spend some time discussing the impact of their own assumptions on the results.  E.g. in the current study it was assumed all wind turbines have LEP. The authors could discuss how valid of an assumption this is for wind turbines in the Dutch North Sea, especially the older existing parks. I also think it would be valuable to calculate a range of emission values, for different LEPs, instead of a single worst-case value. I believe the required input (table 2) is there already. 

Line 304- 308 "Furthermore, it can be assumed that the microplastics emitted from the turbine blades will sink quickly to the ocean floor. As the polymer coating on the wind turbines is PU, which has a density higher than seawater. This additionally means that the exposure time of the microplastics in the higher water column is minimal, and with that its potential impacts on species living here. However, it is likely that degradation rates of these microplastics at the seafloor are slow, due to absence of UV in these areas. Local accumulation of PU microplastics can occur, which can negatively affect species living on the ocean floor."

I don't think the statements on the environmental fate of the microplastics are well supported by the current text. The authors claim the polymer will sink quickly due to the higher density of PU than that of seawater. However, the density of PU is said to be 1 g/cm3 in line 269, which is the same density as that of water. The section would benefit from some references on environmental fate of microplastics in seawater. 

Lastly, the introduction mentions the necessity of this work for the determination of potential mitigation measures. The discussion would benefit from a reflection on this point. What can be learned from the current study in regards to minimizing microplastic emissions from wind turbines? Or what kind of further research would be required to further investigate this? 

The manuscript is well-written, and the authors have made a significant contribution to the field by providing reliable and transparent estimates of microplastic formation and emissions from wind turbines. The study's methodology is sound, and the results are clearly presented and supported by math. Based on the high quality of the manuscript, I recommend that it be published as is.