Mapping of Suitable Sites for Concentrated Solar Power Plants in the Philippines Using Geographic Information System and Analytic Hierarchy Process
Round 1
Reviewer 1 Report
The study is interesting and well conducted. The English is very good and the reading is enjoyable. A larger number of respondents would have given more relevance to the partial results on the importance indices. However, I think that 6 respondents are sufficient.
I think that a minor revision before acceptation is required for the following:
1) It is preferable to better specify the source of DNI values.
2) In table 7 and row 282, DNI is given in kW/m2 instead of kWh/m2
3) The criteria used to define the upper limits of the quantity in figure 7 should be specified. In particular, the maximum distances considered (e.g. 360 km) seem excessively high.
Author Response
Responses to Reviewer 1's Comments
Point 1: It is preferable to better specify the source of DNI values.
Response 1: The source of the DNI values (and the values for the other exclusion factors) was already specified in Table 5, but the website URL for DNI the DNI values has been added in a new footnote.
Point 2: In table 7 and row 282, DNI is given in kW/m2 instead of kWh/m2
Response 2: The unit "kW/m2/year" has been corrected to "kWh/m2/year."
Point 3: The criteria used to define the upper limits of the quantity in figure 7 should be specified. In particular, the maximum distances considered (e.g. 360 km) seem excessively high.
Response 3: We did not use a maximum value for the distances to grid, road, and water. The highest values that appeared on the maps were the values assigned to the lowest score of 1. For instance, the highest distance to grid in the map was 389 km. A bin size of 45 km yields an interval for the score of 1 of 360–405 km, which contains 389 km.
Reviewer 2 Report
Dear authors,
The paper entitled “GIS Mapping of Suitable Sites for CSP Plants in the Philippines Using MCDM-AHP” deals with a gis-based model to find a study the most suitable lands to settle CSP pants in Philippines. The topic of the paper is of interest for the journal “Sustainability” of MDPI editor. The paper is well written and could be accepted after some minor revisions as follows:
- The introduction is well orginized but i would suggest to enrich the bibliography about other studies of gis based model for renewable energy systems such as:
1. Famoso et al. (2020). Designing sustainable bioenergy from residual biomass: Site allocation criteria and energy/exergy performance indicators, Applied Energy, 274, Article number 115315 .
2. Viana et al. (2010). Assessment of forest biomass for use as energy. GIS-based analysis of geographical availability and locations of wood-fired power plants in Portugal, Applied Energy, 87(8), pp 2551-2560.
3. Noon et al. (1996). GIS-based biomass resource assessment with BRAVO, Biomass and Bioenergy, 10(2-3), pp. 101-109.
- The euquations are not in the same format;
- The units of measure should me checked and be in the international system
- The english form is generally good but a deeper proofreading is necessare since many missprints are still present
Kind Regards
Author Response
Responses to Reviewer 2's Comments
Point 1: The introduction is well orginized but i would suggest to enrich the bibliography about other studies of gis based model for renewable energy systems such as:
- Famoso et al. (2020). Designing sustainable bioenergy from residual biomass: Site allocation criteria and energy/exergy performance indicators, Applied Energy, 274, Article number 115315 .
- Viana et al. (2010). Assessment of forest biomass for use as energy. GIS-based analysis of geographical availability and locations of wood-fired power plants in Portugal, Applied Energy, 87(8), pp 2551-2560.
- Noon et al. (1996). GIS-based biomass resource assessment with BRAVO, Biomass and Bioenergy, 10(2-3), pp. 101-109.
Response 1: We do not consider the three papers referred to by the reviewer to be completely significant to the present study. However, we have enriched the review of related literature by discussing in more detail the related site suitability studies reviewed.
Point 2: The euquations are not in the same format;
Response 2: The comment is not specific enough, but we followed a consistent formatting in all the equations.
Point 3: The units of measure should me checked and be in the international system
Response 3: Units of measurements have been checked. All are in SI, except for the following, which we did not convert to SI because they are the units most commonly used in the literature: K for temperatures in solar power plants; L/MWh for water consumption per energy produced by solar power plants; and kWh for DNI.
Point 4: The english form is generally good but a deeper proofreading is necessare since many missprints are still present
Response 4: A deeper proofreading has been done, and errors have been corrected to improve readability.
Reviewer 3 Report
sustainability-1839706-peer-review-v1
GIS Mapping of Suitable Sites for CSP Plants in the Philippines Using MCDM-AHP
Comments and Suggestions for Authors
The paper entitled " GIS Mapping of Suitable Sites for CSP Plants in the Philippines Using MCDM-AHP" is based on a novel algorithm and its applications. The article can be considered only if it is revised.
1. The abstract must be written completely again. I found nothing attractive in the abstract. The abbreviations are not defined.
2. Do not use abbreviations in the title.
3. The authors discussed several times what they are going to propose but did not discuss the research gap or what are the sole reasons for this research.
4. The literature review is not sufficient enough. Please provide more details about the literature review by considering the latest articles.
5. A comparative study if included would have an impact.
6. The authors wrote the conclusion in a rush. Please describe your achievements in detail.
7. The quality of the figures is too low. I did not understand the results in Figure 5. Please explain and them and redraw it
8. In introduction, before starting the mentioned references, there is a need to add 8-9 lines related to the subject of the paper and write in general introduction. After that you should connect them with the references.
9. Before Section 2 (Related works), the authors should include a small summary about the next sections of the paper, for organization reasons. Besides, there must exist some small paragraph between Section 3 and Subsection 3.1, and between Section 4 and Subsection 4.1, also for organization reasons.
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Author Response
Responses to Reviewer 3's Comments
Point 1: The abstract must be written completely again. I found nothing attractive in the abstract. The abbreviations are not defined.
Response 1: The abstract has been rewritten. The two abbreviations used were both defined in their respective first references.
Point 2: Do not use abbreviations in the title.
Response 2: The title has been reworded, and all abbreviations have been spelled out.
Point 3: The authors discussed several times what they are going to propose but did not discuss the research gap or what are the sole reasons for this research.
Response 3: The research gap (the non-existence of CSP plants in the Philippines and the non-existence of suitability studies for them) and the corresponding purposes for the research were already thoroughly explained in Chapter 1, especially in Subsections 1.1–1.3.
Point 4: The literature review is not sufficient enough. Please provide more details about the literature review by considering the latest articles.
Response 4: We have expounded the literature review by discussing in more detail the related site suitability papers reviewed.
Point 5: A comparative study if included would have an impact.
Response 5: Subsections 2.3–2.5 compared the AHP methodologies and exclusion and ranking factors used by related site suitability papers reviewed. The comparison of the MCDM factors was summarized in Tables 2 and 4.
Point 6: The authors wrote the conclusion in a rush. Please describe your achievements in detail.
Response 6: Chapter 5 has been rewritten. A few details have been added, especially the results that satisfied the first objective specified in Chapter 1.
Point 7: The quality of the figures is too low. I did not understand the results in Figure 5. Please explain and them and redraw it
Response 7: Suitable areas cover a very, very small percentage of the country's total land area, and these areas are scattered such that they are not appreciably visible when a magnification that shows the entire Philippines is used. Thus, close-ups were used, such as those in Figure 6; we have however further zoomed in those figures so the suitable areas can be more visible. We also have rearranged the insets in Figure 3. Meanwhile, the histogram of Figure 5 was already sufficiently discussed in the first paragraph of Section 4.4, but we have added a sentence to explain what the axes in the histogram are.
Point 8: In introduction, before starting the mentioned references, there is a need to add 8-9 lines related to the subject of the paper and write in general introduction. After that you should connect them with the references.
Response 8: We are lost as to what this comment meant. The introduction started by giving an overview of the solar energy situation in the Philippines, which required statistics, hence the citations. The introduction then explained what CSP plants are and then proceeded to briefly explain the methodology of the paper.
Point 9: Before Section 2 (Related works), the authors should include a small summary about the next sections of the paper, for organization reasons. Besides, there must exist some small paragraph between Section 3 and Subsection 3.1, and between Section 4 and Subsection 4.1, also for organization reasons.
Response 9: A short paragraph has been inserted before Subsection 2.1. There's already a paragraph before Subsection 3.1. A short paragraph has been inserted before Subsection 4.1.
Reviewer 4 Report
I appreciate the authors for presenting the research work on, “Mapping of Suitable Sites for Concentrated Solar Power Plants in the Philippines Using Geographic Information System and Analytic Hierarchy Process”. The paper is well written for identifying suitable sites for concentrated solar power (CSP) plants with the help of GIS. Following are the suggestions for better understanding of readers. Following is the observations from the content of paper:-
1) The sample survey based on questionnaire prepared by author’s has very poor response and hence the findings based on it may be improper. If possible authors may neglect it.
2) For ranking factor, when the voltage rating of the nearest grid line may link with the proposed capacity of the CSP.
Authors’ are requested to answer the following questions in their paper:-
1) What is the total current power generation and load requirements of Philippines?. This will help reader to understand the need of CSP in Philippines.
2) Out of 1,194.34 MW solar power how much is connected to the grid?
3) In multi criteria decision making (MCDM) can we add the cost as one of the factor compared with the solar PV and CSP.
4) For small hydro power plants, we consider the dependability factor based on previous meteorological data. Can we include the same in your AHP model?
Comments for author File: 
Comments.pdf
Author Response
Responses to Reviewer 4's Comments
Point 1: The sample survey based on questionnaire prepared by author’s has very poor response and hence the findings based on it may be improper. If possible authors may neglect it.
Response 1: The individual consistency ratios were above the threshold of 0.1, but this is often the case for studies where the number of factors exceeds four. It was through getting the geometric mean of the individual responses that the consistency ratio went below the threshold. This method tempered the inconsistency of the individual responses and allowed for a more balanced judgment of the priorities across the different stakeholders. The results in this part of the study cannot be excluded or ignored because it is an essential part of the methodology; they were the weights that were used in computing the final suitability score of the areas.
Point 2: For ranking factor, when the voltage rating of the nearest grid line may link with the proposed capacity of the CSP.
Response 2: The sizing of the CSP plants based on the capacity of the grid nearest to the suitable sites is beyond the scope of this study; our goal only was to locate the most suitable sites. This has been clarified in Subsection 1.4.
Point 3: What is the total current power generation and load requirements of Philippines?. This will help reader to understand the need of CSP in Philippines.
Response 3: More statistics on the current renewable energy landscape of the Philippines have been inserted in the introduction, and they have been compared with the NREP 2030 goal to emphasize the need for more renewable sources of energy, including CSP.
Point 4: Out of 1,194.34 MW solar power how much is connected to the grid?
Response 4: All of those are connected to the grid; this information has been inserted in the third paragraph of the introduction. More recent statistics have been found, so the capacity numbers have all been updated.
Point 5: In multi criteria decision making (MCDM) can we add the cost as one of the factor compared with the solar PV and CSP?
Response 5: The economics of the CSP plants is beyond the scope of the study. Based on the International Renewable Energy Agency, the levelized cost of electricity for CSP is still more than double that of solar PV. As such, the cost of CSP technology needs to go down significantly for CSP plants to be competitive in mainstream energy generation. Furthermore, cost will come into play after the suitability study since different technologies have different costs, and these can be case studies for specific areas that are identified as highly suitable.
Point 6: For small hydro power plants, we consider the dependability factor based on previous meteorological data. Can we include the same in your AHP model?
Response 6: The authors did not encounter any paper that used a dependability factor in selecting suitable sites for a solar power plant. We think the contribution of previous data in determining how suitable a certain area is is already taken care of by the fact that the solar and typhoon data (the meteorological data) gathered in our study already included a huge amount of past data. The DNI map downloaded from the Global Solar Atlas averaged data across years from 1994 to 2018. Meanwhile, the typhoon frequency map was created from typhoon tracks that hit the Philippines from 1990 to 2021.
Round 2
Reviewer 3 Report
sustainability-1839706-peer-review-v2
Mapping of Suitable Sites for Concentrated Solar Power Plants in the
Philippines Using Geographic Information System and Analytic Hierarchy Process.
In this revised manuscript, author shares a study on mapping of suitable sites for concentrated solar power plants in the Philippines using geographic information system and analytic hierarchy process. While the topic is relevant, there are many technical and novelty issues. Some of the main issues are as follows:
The introduction section is very weak. It does not give a comprehensive background and does not act as a supporting structure to the study.
The results and discussion sections lack insight. The study is too narrow to explain the hypotheses stated in the figures.
In the discussion section, references to previous studies on the subject in the literature are quite limited.
Finally, the manuscript is not possible for the publication to be revised and published within the scope of these criticism. For these reasons, I propose the rejection of this revised manuscript.
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Author Response
Responses to Reviewer 3's Comments (Round 2)
Note: These responses have been priorly included in the rebuttal letter accompanying this resubmission.
Point 1: The introduction section is very weak. It does not give a comprehensive background and does not act as a supporting structure to the study.
Response 1: The authors disagree with the comment. Brevity is a skill that is difficult to master but is essential in keeping a research article straight to the point and as concise as possible. We believe that what the reviewer is expecting in the introduction section is the big-picture discussion of the renewable energy situation in the world with subsequent narrowing down of focus to the Philippines and to concepts of concentrated solar power (CSP) as a potential energy source. While many manuscripts include these preliminary discussions, the authors decided to go straight to discussing the solar energy situation in the Philippines to paint the picture of the current landscape. The expected audience of the paper, and the current special issue, is a cohort of renewable energy researchers who have the basic background in renewable energy systems, which is a subject in our university’s undergraduate program. In fact, three of the four authors of this manuscript worked on this study for an undergraduate requirement in their degree program. The expected audience would be of the same level or of higher qualifications. The necessary discussions on the technology and the methods used in the study have been moved to the related literature section to provide a structured framework of the concepts relevant to this study.
Point 2: The results and discussion sections lack insight. The study is too narrow to explain the hypotheses stated in the figures.
Response 2: The authors disagree. The insights presented in this work are the information on suitable sites for CSP in the Philippines; no other study has done this before. The work is an application of multiple methods of suitability studies previously used in other renewable energy sources, as well as of other countries, in the context of CSP and of the Philippines. There is no study that has presented the same output as this present body of work. That is the insight that this study is presenting. The comment that the study is too narrow is vague. What does the reviewer expect? The results presented speak for themselves. The application of weighted scoring and exclusion to the areas of interest, using the methods commonly employed in other studies, resulted in the suitability maps presented. If there is any part of the study that is not technically sound, then the reviewer should highlight that part. Commenting on something very general without any elaboration of why the reviewer thinks that way does not provide insight on the issue being raised.
Point 3: In the discussion section, references to previous studies on the subject in the literature are quite limited.
Response 3: Why is it necessary to compare suitability maps of other studies, presumably of other countries, against the current study results? There is no need to compare as the results of this study are very specific to the Philippines. If certain aspects of the results of this study turn out to be similar to other studies, those are coincidental since the input data are independent. Local conditions, including sociopolitical and regulatory situations, geographic and environmental aspects, and other relevant factors, are expected to be different from country to country. What are transferrable from previous studies to the current study would be the methods and some technical assumptions that are detached from local conditions. There is no point in comparing the results of the analytic hierarchy process or of the exclusion and of the factor scoring in the suitability analysis since these are specific to the Philippines. Additionally, references to previous studies have all been thoroughly done in the related literature section.
