Material Demand and Contributions of Solar PV End-of-Life Management to the Circular Economy: The Case of Italy

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The examines material demand and contributions of solar PV end of life management to circular economy. This topic is well researched, and I believe there a lot of clarifications needed. I have made a few recommendations which I hope will improve the manuscript.

Introduction

1. The title of the research does not really reflect the content as the work seeks to explore the circularity of Solar PV in Italy. This should be corrected or changed.
2. There is a huge literature gap in the introduction as the authors do not make any references to relevant research in this area and why this study is important. Review and incorporate accordingly. See works like, A scientometric review of trends in solar photovoltaic waste management research; An evaluation of the impact framework for product stewardship on end-of-life solar photovoltaic modules: An environmental lifecycle assessment; Recycling of solar photovoltaic panels: Techno-economic assessment in waste management perspective; Environmental emissions influencing solar photovoltaic waste management in Australia: An optimised system network of waste collection facilities.
3. What specifically is new that this research seeks to address and what makes it different from other LCA studies on Solar Photovoltaics waste. Make the research gap and contribution clear since this arear is comprehensively covered either in Italy or elsewhere.
4. What does circularity mean to the authors, the meaning is not quite captured in the literature making it difficult to link this to LCA. The parameters of what the authors refer as circularity should be explained.

Method

5. The methodology is not very clear and does not follow the prescribed LCA methodology. The functional unit, LCI, assessments and many more are missing from the LCA methods.
6. The data does not add anything new, the use of generic data and ecoinvent has already been achieved in other studies. What is unique about your datasets (background and foreground data). And how is this integrated with circularity.
7. Why the use of the ReCiPe method but not the other recommended methods since you are considering Italy. Explain why the use of for example the midpoint and endpoint indicators, what is the difference and why the need to refer to them when interpreting your results, especially in this study.
8. I believe the section solar energy development is not appropriately situated in this study. This should go to the introduction or literature section.

Results and Discussion

9. How did authors arrive at the material demand for solar PV development as this is not clear in the results.
10. How the results are presented is very confusing. Create a section to initially discuss the scenarios before they come into the results.
11. Authors should present the results of the LCA in a proper manner showing the various indicators and how they affect the modelling. How was the LCA modelled. Why 2030 and 2040. How was this calculated.

Discussion

12. The discussion should be clearly segmented with relevant subtopics to clearly articulate the material demand from the interpretation of the LCA.
13. How does this benefit the government, industry and academia. This should be well covered and discussed.

Conclusion

14. The conclusion should be separated.
15. Again, emphasize in the conclusion why this research was necessary and its contribution to academia, government or industry.

Others

16. There was no supplementary material attached to the submission.

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The paper aims to assess the impact of a circularity approach on the end-of-life management of PV in Italy. 

The paper has several shortcomings and cannot be published in the present form:

1. The novelty of the paper is not clearly demonstrated. The current state-of-the-art is not comprehensively presented (missing relevant papers are not included in the assessment, like "Research and development priorities for silicon photovoltaic module recycling to support a circular economy", "Management of end-of-life photovoltaic panels as a step towards a circular economy", "Circular Economy in Photovoltaics", "Prioritizing circular economy strategies for sustainable PV deployment at the TW scale", "Assessing life cycle environmental impacts of solar photovoltaics in India with a focus on end-of-life disposal", "A new perspective for evaluating circularity of photovoltaic module recycling and technology developments", "Life Cycle Assessment of Disposed and Recycled End-of-Life Photovoltaic Panels in Australia", or "Environmental Impact Assessment of crystalline solar photovoltaic panels’ End-of-Life phase: Open and Closed-Loop Material Flow scenarios").
2. Based on a broad and detailed description of the state-of-the-art, the identified research gaps, and the related research questions the paper aims to address are unclear. For example, why is Italy considered a case study?
3. In the methodology section it is unclear and not explained/justified why some KPIs are adopted and other ones are not included in the study. Table 2 reports a list of impacts which are assessed, but no clear explanation is given in the text about how they are computed, what the inventories used are. For example, a materials list of the technologies listed in Figure 1 is missing. A list of conversion factors from materials to the KPIs is missing as well (could be added in the supplementary materials, but at least provided so that calculations can be replicated). 
4. Recovery/recycling rate definition and values are not introduced in the methodology section. What the target values adopted are is unclear.
5. It is unclear why the BAU scenario should be landfilling. Indeed, there's no BAU related to PV end-of-life management at scale (see "Photovoltaic waste assessment in Italy"). The expected operation life of a PV module is > 25 years, so now only damaged PV modules are disposed of, which is a negligible fraction. I would recommend reformulating the baseline scenario. 
6. A sensitivity analysis should be introduced to address the uncertainties about future forecasts and the impact on the KPIs.

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

Dear authors,

I read carefully your research article and I have a few simple questions:

 

-What steps do you suggest to make recycling and reuse of solar panels more effective in real-world applications?

-How did you choose Italy as the case study, and could the results be applied to other countries?

-What challenges do you see in collecting and recycling old solar panels in practice?

-How reliable is the data used for forecasting material demand up to 2040?

-Do you consider any social or economic benefits from recycling solar PV, besides environmental ones?

 

Regards

Author Response

Please see the attachment

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

All my comments are addressed 

Reviewer 2 Report

Comments and Suggestions for Authors

The authors deeply reviewed the paper according to previous suggestions. All the shortcomings highlighted have been properly addressed. The paper is now ready for publication.