A Complete and High-Resolution Estimate of Sardinia’s Rooftop Photovoltaic Potential
Round 1
Reviewer 1 Report
In this paper the authors study the problem of resolution estimate of sardinia’s rooftop photovoltaic Potential. Consistent power system operation is very important to both power utilities and consumers. This paper proposes a complete census estimate of rooftop photovoltaic production potential for the region of Sardinia, using a procedure that integrates satellite irradiance data with surface elevation and cadastral data to obtain a very high spatial resolution estimate.
The topic is quite interesting, but I have comments. It is necessary to expand the Abstract, indicate briefly the results obtained. The introduction should place the proposed approach on the background of existing and known solution presented in literature. Also the importance of the research field should be stressed.
In my opinion, the article should give specific examples of the use of different types of solar panels. Each type of solar panel will produce a different amount of electrical energy. For example, to show how much electricity will be generated when using monocrystalline solar panels of different types, inverters of different types. Also of great importance is the cross-section of the wire to the supply substation. Provide a table with the characteristics of different types of monocrystalline panels and inverters. It is also necessary to take into account the contamination of solar panels with dust, which will lead to a decrease in generation. What costs will be required for the maintenance of rooftop solar power systems? Perhaps the buildings should also be divided into groups according to the accessibility to maintenance of rooftop solar power plants.
The presented report is at a very high scientific level. I believe that the present study has a significant scientific and applied contribution, which is strongly emphasized in the basically reporting volume. A slight clarification can be made in the abstract part, where the quality of the research can be enhanced. In the conclusion, it is necessary to describe what is the optimal density of the photocell of the solar monocrystalline panel should be used for rooftop solar power plants. It is also desirable to indicate what the maintenance costs of solar power plants will be, depending on the type of building, the number of storeys, access to the roof.
Author Response
In this paper the authors study the problem of resolution estimate of sardinia’s rooftop photovoltaic Potential. Consistent power system operation is very important to both power utilities and consumers. This paper proposes a complete census estimate of rooftop photovoltaic production potential for the region of Sardinia, using a procedure that integrates satellite irradiance data with surface elevation and cadastral data to obtain a very high spatial resolution estimate.
The topic is quite interesting, but I have comments.
We thank the reviewer for his interest in our work and for his comments that allowed us to improve the manuscript
It is necessary to expand the Abstract, indicate briefly the results obtained.
Thank you for your comment, we have rewritten the abstract giving a better description of the methodology and its results
The introduction should place the proposed approach on the background of existing and known solution presented in literature.
Thank you for your comment, in this new revision we have extended the introduction by better highlighting the methodological contribution and underlining the differences from the literature. Changes to the text are colored blue for easier reviewing
Also the importance of the research field should be stressed.
Thank you for your comment, we have extended the introduction by trying to put more emphasis on the relevance of this area of research
In my opinion, the article should give specific examples of the use of different types of solar panels. Each type of solar panel will produce a different amount of electrical energy. For example, to show how much electricity will be generated when using monocrystalline solar panels of different types, inverters of different types. Also of great importance is the cross-section of the wire to the supply substation. Provide a table with the characteristics of different types of monocrystalline panels and inverters.
We thank you for the comment. We certainly agree that different technologies can have a great influence on the technical potential of panels, the conversion efficiency of new technologies is in fact continuously increasing, and in addition, grid characteristics can affect the possibilities of distributed generation from renewable sources. Our work, however, focuses on a metodology for large-scale and highly detailed estimation of the geographic potential of rooftop PV. For the technical and economic potential directly associated with it, we used the most common technology available on the market.
A technical, and especially economic, comparison between different technologies is beyond the scope of this paper and probably beyond our expertise, which is why we are making the data from our analysis available for other researchers to conduct research on the topic you have rightly highlighted.
It is also necessary to take into account the contamination of solar panels with dust, which will lead to a decrease in generation.
We thank you for your comment. Actually, our estimate takes into account performance degradation due to contamination with dust through a combined system loss L = 14%, as suggested by PVGIS procedures.
What costs will be required for the maintenance of rooftop solar power systems?
We thank you for your comment. We have included maintenance costs in the OPEX parameter of the economic analysis, estimated at 50€/kWp/y for the Italian market including maintenance, insurance and management. The estimate is taken from reference Lazzeroni et al., to which we refer for further discussion of economic aspects related to the Italian market.
Perhaps the buildings should also be divided into groups according to the accessibility to maintenance of rooftop solar power plants.
We thank you for the comment, a rough estimate could be based on the height and type of the building, to differentiate maintenance costs associated. Our cost estimate is obtained through an average cost for installations in Italy, and an in-depth cost analysis related to the different types of buildings is beyond the scope of this paper.
The presented report is at a very high scientific level. I believe that the present study has a significant scientific and applied contribution, which is strongly emphasized in the basically reporting volume. A slight clarification can be made in the abstract part, where the quality of the research can be enhanced. In the conclusion, it is necessary to describe what is the optimal density of the photocell of the solar monocrystalline panel should be used for rooftop solar power plants. It is also desirable to indicate what the maintenance costs of solar power plants will be, depending on the type of building, the number of storeys, access to the roof.
Thank you for your comment, the in-depth research you refer to is mainly related to an economic optimization also in relation to different PV panel technologies, which is beyond the scope of this paper, which focused on estimating geographic potential as a basis for subsequent elaborations. In fact, we are making our results available to the community in the hope that other researchers, more competent in economics than we are, will be able to elaborate on these aspects. This analysis should take into account economic and regulatory scenarios, both for accessibility to funding and for the availability and costs of different technologies, with findings that will be dependent on a changing national and international economic scenario. We have extended the conclusions by including your suggestions as an indication for further investigation of this analysis.
Reviewer 2 Report
The work has a high potential to publish in the Applied Sciences Journal. However, several amendments are needed for the manuscript to achieve the standard of the respective journal. Below are several suggestions to improve the manuscript:
1. Gives full name when first mentioned the short form. For example, geographic information systems for GIS and Light Detection and Ranging for LiDAR. Several short forms are not given in full names when first mentioned such as OPEX, CAPEX, and TD.
2. In the abstract, the authors should include a summary of the methodology (for example, software used) and the results obtained. From the results, briefly describe the discussion in the abstract as well.
3. In the introduction section, works of literature are not mentioned or explain in detail the previous similar works and the author should include the differences between this manuscript and the previous works so that novelty can be highlighted.
4. Figures and tables should be mentioned in the text before presenting them. For example, sentences from lines 90 until 93 should be brought to line 89 in the manuscript.
5. A flow chart of the summary of the methodology should be included to ease the reader's understanding of the manuscript. Through this, the readers are able to see the overall process and correlation between one step to another.
6. Mention and explain each equation. For example, at line 168, the mean annual irradiance is obtained from the sum of several contributions as shown in Equation (1). Equations (2), (3) and (4), on the other hand, represent calculations on mean annual irradiances due to the direct component, diffuse component from the sky and diffuse component from the ground.
7. Parameters in the estimation of incident radiation should include works of literature and justify why the authors chose the values. For example, efficiency and surface areas in lines 210 and 211 should include literatures in the text and elaborate more on why the values were selected.
8. Avoid using “we think” (Example, in line 311). All of the research works should be justified clearly and not express the thoughts generally.
9. The font in Figure 11 is so small and unreadable.
10. Lines 385 until 387 are unnecessary since the authors have already mentioned them in the conclusions.
Author Response
The work has a high potential to publish in the Applied Sciences Journal. However, several amendments are needed for the manuscript to achieve the standard of the respective journal. Below are several suggestions to improve the manuscript:
Thank you for your consideration and time in revising our work. We have tried to respond thoroughly to all your comments which were very helpful in improving the manuscript. This new revision has also been proofread for what concerns the language and we hope that it can be considered acceptable
1. Gives full name when first mentioned the short form. For example, geographic information systems for GIS and Light Detection and Ranging for LiDAR. Several short forms are not given in full names when first mentioned such as OPEX, CAPEX, and TD.
Thank you for your comment, we have revised the text by including the full name for all acronyms and inserted a list of them at the end.
2. In the abstract, the authors should include a summary of the methodology (for example, software used) and the results obtained. From the results, briefly describe the discussion in the abstract as well.
Thank you for your comment, we have rewritten the abstract giving a better description of the methodology and its results
3. In the introduction section, works of literature are not mentioned or explain in detail the previous similar works and the author should include the differences between this manuscript and the previous works so that novelty can be highlighted.
Thank you for your comment, in this new revision we have extended the introduction by better highlighting the methodological contribution and underlining the differences from the literature. The scientific contribution is related to the extremely effective algorithm used for time integration of solar irradiance reaching a surface, accounting for the shading effects of other buildings, which can be applied to the roof surface of buildings in the entire region with a spatial resolution of 1 m. Our procedure allows to combine a very high detail with the extent of the area of analysis. Similar procedures are proposed in the literature only for limited areas, and are difficult to scale to entire regions. The procedures proposed in the literature for such large areas are based on sample analyses or estimates based on building types, and therefore cannot achieve the detail we propose. Changes to the text are colored blue for easier reviewing
4. Figures and tables should be mentioned in the text before presenting them. For example, sentences from lines 90 until 93 should be brought to line 89 in the manuscript.
We thank you for your comment, the exact positioning of the tables and figures depends on the Latex document processing system, we have limited control on it. The journal editor will have much more freedom in positioning tables and figures in the correct position.
5. A flow chart of the summary of the methodology should be included to ease the reader's understanding of the manuscript. Through this, the readers are able to see the overall process and correlation between one step to another.
We thank you for your comment, we have outlined the procedure in a dedicated flowchart, as suggested.
6. Mention and explain each equation. For example, at line 168, the mean annual irradiance is obtained from the sum of several contributions as shown in Equation (1). Equations (2), (3) and (4), on the other hand, represent calculations on mean annual irradiances due to the direct component, diffuse component from the sky and diffuse component from the ground.
Thank you for your comment, in the new revision we have properly described all equations comprehensively.
7. Parameters in the estimation of incident radiation should include works of literature and justify why the authors chose the values. For example, efficiency and surface areas in lines 210 and 211 should include literatures in the text and elaborate more on why the values were selected.
You are absolutely right, in the new revision we have included and commented on the appropriate references for the parameters used in the equations
8. Avoid using “we think” (Example, in line 311). All of the research works should be justified clearly and not express the thoughts generally.
Thank you for your comment, we have revised the text accordingly by clearly justifying our conclusions and the references used
9. The font in Figure 11 is so small and unreadable.
Thank you for your comment, we have revised the figure to make it more readable
10. Lines 385 until 387 are unnecessary since the authors have already mentioned them in the conclusions.
We are very sorry but we could not interpret your comment, the lines mentioned correspond to the conflict of interest statement and the first reference. There is probably an error in the line number mentioned. If you meant the sentences about the future research, we removed the one in the Discussion chapter.
Reviewer 3 Report
1) Why Authors focues on Sardinia's Rooftop PV is there any special reason?
2) Abstract should be re-writtern your abstract does not matches your work
3) Authors can also propose in introduction some alternate methods and cooling technologies that was proposed by different studies. As a reader I can give some hints, for every 1 o C degree rise in ambient temperature the efficiency will fall from 0.4-0.5%. Therefore, to stabilize a cooling method can be imposed. Moreover, using such type of cooling methods efficiency, and power will be improved and can cite some articles
a) https://0-doi-org.brum.beds.ac.uk/10.3390/s22176367
b) Experimental assessment of thermoelectric cooling on the efficiency of PV module
4) Authors can propose a comparison table in results and sections with other studies at least 10 works
5) conclusions can be improved
Author Response
We thank you for your attention to our work and for your comments that allowed us to improve the manuscript in this new revision
1) Why Authors focues on Sardinia's Rooftop PV is there any special reason?
This work represents one of the results of a research project funded by the Autonomous Region of Sardinia, from which the specific scope of investigation naturally follows. Sardinia represents an interesting area of study regardless, given its insularity, the characteristics of the electricity transmission and distribution grid, the characteristics of energy production and consumption, and the interest of the main stakeholders in the power system in transforming the island's entire power system to be entirely renewable.
2) Abstract should be re-writtern your abstract does not matches your work
Thank you for your comment, we have rewritten the abstract giving a better description of the methodology and its results
3) Authors can also propose in introduction some alternate methods and cooling technologies that was proposed by different studies. As a reader I can give some hints, for every 1 o C degree rise in ambient temperature the efficiency will fall from 0.4-0.5%. Therefore, to stabilize a cooling method can be imposed. Moreover, using such type of cooling methods efficiency, and power will be improved and can cite some articles
a) https://0-doi-org.brum.beds.ac.uk/10.3390/s22176367
b) Experimental assessment of thermoelectric cooling on the efficiency of PV module
Thank you for the comment. This work is focused on estimating the geographic potential for Sardinia; as for the technical and economic potential, these are extremely dependent on the evolution of technology, and on the regulatory and economic scenario, so we conducted the analysis with the most common technology used in Italy at this time. We are aware that the proposed technology, like others, may provide room for improvement for the overall performance of the plants, but a full examination of these is beyond the scope of this paper. We are distributing the results of our analysis in open access so that other researchers can also investigate these aspects further
4) Authors can propose a comparison table in results and sections with other studies at least 10 works
Thank you for your comment; unfortunately, there is no extensive literature analyzing the specific problem for the region, and it makes relatively little sense to compare our result with that for other geographic areas, which differ in terms of building characteristics and, above all, climatic irradiance conditions. In the discussion, we compared ourselves with the only recent work we are aware of that addresses the problem of assessing photovoltaic potential for the entire European territory and thus also for the island.
5) conclusions can be improved
Thank you for your comment, we have extended the conclusions by better highlighting the results achieved and the subjects in our view worthy of further study
Round 2
Reviewer 1 Report
All comments have been corrected. The article may be published. Good luck to the authors.
Author Response
We thank the reviewer for taking the time to carefully read our work, and for the valuable advice that enabled us to improve it.
Reviewer 2 Report
All of the comments have been addressed in the manuscript.
Author Response
We thank the reviewer for taking the time to carefully read our work, and for the valuable advice that enabled us to improve it.
Reviewer 3 Report
1) Authors have not addressed my comment number 3 if authors can consider my comment number then the government or the individual house holder whoever want to install PV plants for domestic appliance can consider the knowledge of cooling.
2) my comment number 4 also authors not responded well a comparison work must be done either higher power or lower power. Therefore, government will understand the prospective behind the other countries. Atleast five literature works must be addressed.
3) Finally, I recommended authors should refer to conclusions because conclusion must be improved
Author Response
Dear Reviewer,
We note with much surprise that your assessment of our work has significantly worsened in all items as a result of our revision, and frankly we do not quite understand why.
1) Authors have not addressed my comment number 3 if authors can consider my comment number then the government or the individual house holder whoever want to install PV plants for domestic appliance can consider the knowledge of cooling.
Regarding your comment 3, we reiterate that our study uses standard technology for estimating technical potential, as far as the Italian market is concerned, and also for the international market to the best of our knowledge, panel cooling is not standard technology. Therefore, we do not think it is relevant to cite the two works as you are asking us.
2) my comment number 4 also authors not responded well a comparison work must be done either higher power or lower power. Therefore, government will understand the prospective behind the other countries. Atleast five literature works must be addressed.
Regarding point 4, we compared our results with the only other work that analyzed the geographical area of our interest. If you know of 5 other works on estimating the photovoltaic potential of the Sardinia region we kindly ask you to direct us to them.
3) Finally, I recommended authors should refer to conclusions because conclusion must be improved
Finally for point 5, the conclusions have been entirely rewritten in this new revision also based on your input. We therefore ask you for more precise indications of your objections to it.
