Analysis of Soiling Loss in Photovoltaic Modules: A Review of the Impact of Atmospheric Parameters, Soil Properties, and Mitigation Approaches

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript presents a comprehensive review of the soiling influence on the PV modules' performance. A high number of literature references have been cited many of which, including outdoor and indoor investigations, have been discussed. Much attention was paid to environmental parameters (wind, humidity, rainfall), PV systems’ configuration (tilt) and dust properties influencing the soiling of the PV modules. Cleaning techniques were also addressed. In my opinion, the presented review is interesting and can be published. Minor suggestions have been listed below.

1.      The abstract and the conclusions are relatively general compared to the presented results. I would suggest adding the most important findings of the literature reviewed.

2.      ‘/’ should be probably removed from the last part of the equations (1) and (2) or something is missing. Moreover, ‘alpha’ is not of the same shape in equations (1) and (3) and Nomenclature table.

3.      Figure 4 could be of better quality to see the details. The description of Figure 4 should be placed directly under the figure.

4.      In lines 217 and 405 ‘m2’ should be replaced using ‘m^2’ and in line 299 ‘w/m²’ should be replaced by ‘W/m²’.

5.      Attention should be paid to the permission to use figures copied from other journals.  

Author Response

The manuscript presents a comprehensive review of the soiling influence on the PV modules' performance. A high number of literature references have been cited many of which, including outdoor and indoor investigations, have been discussed. Much attention was paid to environmental parameters (wind, humidity, rainfall), PV systems’ configuration (tilt) and dust properties influencing the soiling of the PV modules. Cleaning techniques were also addressed. In my opinion, the presented review is interesting and can be published. Minor suggestions have been listed below.

We want to thank the Reviewer for the careful review and for sharing the value of this work for the PV community. All the comments have been addressed.

The abstract and the conclusions are relatively general compared to the presented results. I would suggest adding the most important findings of the literature reviewed.

Thank you for bringing this to our attention. As you pointed out, we had rebuilt the conclusion section because it was comparable to an abstract. Furthermore, we have edited the Abstract too. As this is a review publication, we analysed the important findings section by section and noted several key issues within each part. We discussed the essential elements for the overall review in the abstract, and in the conclusion, we attempted to summarize the review without repeating specific discussed portions. Furthermore, as a crucial learning, section 6 discusses recommendations for future study directions.

 ‘/’ should be probably removed from the last part of the equations (1) and (2) or something is missing. Moreover, ‘alpha’ is not of the same shape in equations (1) and (3) and Nomenclature table.

Thank you, sir, for the important point. We have modifies as pointed out.

Figure 4 could be of better quality to see the details. The description of Figure 4 should be placed directly under the figure.

Thank you for the comment. The image has been enlarged and separated. The description was placed below the figure.

In lines 217 and 405 ‘m2’ should be replaced using ‘m2’ and in line 299 ‘w/m2’ should be replaced by ‘W/m2’.

We want to thank the Reviewer for this comment.  We are sorry for this error.  We have rectified as advised.

Attention should be paid to the permission to use figures copied from other journals.

Thank you for being observed. When using photos to prepare the manuscript, the appropriate steps or precautions were taken, and proper citation was provided.

We hope you will find that all comments have been given proper consideration. Thanks for helping to improve the quality of the work.

Reviewer 2 Report

Comments and Suggestions for Authors

The authors present a compelling review on the topic of soiling losses in solar power production - a worthy effort in my view.

The problem of soiling losses is well described, and how it is measured, modeled, and handled with.

A few comments are entitled:

1. The resolution of Fig. 1 is too low to allow a meaningful appreciation of the data it is supposed to convey.

2. The notation of Eqs. 1 and 2 is unclear. What are the meanings of the  \propto signs and the division sign in the denominators of the respective equations?

In conclusion, this is an important review on an important subject. I recommend publication given that the minor comments I raised are properly dealt with.

Author Response

The authors present a compelling review on the topic of soiling losses in solar power production - a worthy effort in my view. The problem of soiling losses is well described, and how it is measured, modeled, and handled with. A few comments are entitled:

Thank you for the positive comment on my work and the valuable suggestions.

The resolution of Fig. 1 is too low to allow a meaningful appreciation of the data it is supposed to convey.

Thanks for the valuable point. In order to enhance the clarify of the plots, Fig. 1 has now been split into two figures (Figs. 1 and 2) and their resolution has been improved.

The notation of Eqs. 1 and 2 is unclear. What are the meanings of the  \propto signs and the division sign in the denominators of the respective equations?

We wish to thank the Reviewer for this question. We sorry for the confusion.  The notation of Eqs. 1 and 2 is addressed in nomenclature section. So, to avoid the repetition of words it was excluded from the section, but we have resumed the insertion.

In conclusion, this is an important review on an important subject. I recommend publication given that the minor comments I raised are properly dealt with.

We hope you will find that all comments have been given proper consideration. Thanks for helping to improve the quality of our work.

Reviewer 3 Report

Comments and Suggestions for Authors

  In this review, the authors focus on the impact of soiling (i.e., dust deposition) on their efficiency and economics of PV power systems, discussing the factors that govern soiling on PV modules and assessed the power losses reported in the literature for various locations. The authors outline some indoor studies to understand the effect of environmental circumstances on soiling, although these are not sufficient yet to identify long-term dust deposition patterns for a given location. Followingly, the advantages and disadvantages of different mitigation techniques and tools have been compared. In the end, the authors explicitly recommend the feasible requirements for future research on anti-soiling and cleaning technology. Overall, this review is of interest to the community of PV. After reading through the whole manuscript, I do learn a lot. I strongly recommend its publication.

Author Response

 In this review, the authors focus on the impact of soiling (i.e., dust deposition) on their efficiency and economics of PV power systems, discussing the factors that govern soiling on PV modules and assessed the power losses reported in the literature for various locations. The authors outline some indoor studies to understand the effect of environmental circumstances on soiling, although these are not sufficient yet to identify long-term dust deposition patterns for a given location. Followingly, the advantages and disadvantages of different mitigation techniques and tools have been compared. In the end, the authors explicitly recommend the feasible requirements for future research on anti-soiling and cleaning technology. Overall, this review is of interest to the community of PV. After reading through the whole manuscript, I do learn a lot. I strongly recommend its publication.

We wish to sincerely thank the Reviewer for the valuable words.