Assessment of Environmental and Economic-Financial Feasibility of Biogas Plants for Agricultural Waste Treatment
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsContribution:
Regarding the manuscript, it is not observed that it is a novel or relevant research topic for the academic community.
1. Introduction:
The contribution of the manuscript is not noted.
2. Materials and methods.
The methodology used is not observed.
3.- Results
It is not noted how the results were obtained nor is the literature used in this manuscript discussed.
4. Discussion
There is no discussion based on the literature used in this manuscript.
Author Response
The novelty and significance of this work are highlighted in Abstract and Introduction sections. The contribution of the manuscript is noted now, in the new re-submitted article. The methodology was also revisioned and changed as you can see those changes hightlighted in the re-submitted manuscript. It is noted how the results were obtained and so is the literature used in this manuscript discussed in the re-submitted paper. There is also discussion based on the literature added in the new version of manuscript.
Thank you once again for your valuable advice and help. Best regards, authors.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe paper is rather interesting, insightful, and valuable from both theoretical and empirical perspectives. Nevertheless, there is some recommendations that might help to improve the quality of the paper:
1) The Introduction section need to be redesigned because it does not bring to feasible understanding of the research problem. In its current shape it seems to be a little bit disintegrated and fragmental. It is better not to describe each paper separately but to provide a general overview considering following key points: 1) importance, prons and cons of biogas production in terns of energy security and sustainability; 2) biogas plants: role in energy security, measurement of performance, positive and negative aspects of its operating; 3) formalization of economic and financial perspectives of biogas plants’ operating; 4) clarification of the research gap and the aim of the research. Basically, it is just needed to rebuild this chapter with trying not to describe a specific paper and results but to clarify the urgency of the research and its objectives;
2) it seems that the Results section need to be expanded because in the title it is mentioned “environmental and economic-financial feasibility of biogas plants” but it still lack of environmental proxies. Moreover, it is better to provide more in-depth benchmark cross-country analysis of biogas plant operating. It is needed more analytical data to be considered for making some conclusions about biogas plants financial, economic and environmental performance.
Best regards,
Comments for author File: 
Comments.pdf
Minor editing of English language required
Author Response
Firstly, thank you very much for your review of our manuscript. The following changes you were made based on your recommendations to improve its quality as you suggested: Not only introduction section, but all sections were edited since you also suggested to extend the results section we added more analyses including more analytical data analyses as you recommended. Based on your review we re-designed the introduction and provided a general overview considering key points you suggested. All changes that were made you can find in the re-submitted manuscript, in which are all changes higlighted. Thank you once again for your help. Best regards, authors.
Reviewer 3 Report
Comments and Suggestions for AuthorsIn this manuscript (sustainability-2886094), the prerequisites and consequences of the use of biogas plants at the macro and micro levels were assessed to search for opportunities to reduce the cost of its installation and make it more affordable for individual farms. The use of individual biogas plants can be a means of solving many energy-environmental and financial-economic problems, and importantly this work investigated the cost of purchasing and operating biogas plants based on the data of a private company and assessed the cost of construction of a biogas plant and more. Overall, this work is suitable for publication in this journal after minor revisions.
Firstly, the English language can be further polished and improved.
Secondly, the data and results can be shown in other forms instead of only tables.
Thirdly, the novelty and significance of this work should be highlighted in Abstract and Introduction sections.
Lastly, the sustainable aspects of this work should be clearly discussed in Discussion section based on the environmental and economic-financial feasibility of biogas plants.
Comments on the Quality of English LanguageFurther polishing
Author Response
Firstly, we would like to thank you very much for your review of our manuscript. The following changes you were made based on your recommendations to improve its quality as you suggested: we were working on improvement of our English in the manuscript, data that we agreed on which can be shown also as an figure has now its new form (figure 1 and figure 2, previously table 1), we did our best to highlight novelty and significance of this work in Abstract and Introduction sections, we also re-designed all sections of manuscript, introduction, materials and methods, results as well as discussion and conclusions. Thank you once again very much for your advice and help. Best regards, authors.
Reviewer 4 Report
Comments and Suggestions for AuthorsReview on paper ‘Assessment of environmental and economic-financial feasibility of biogas plants for agricultural waste treatment’
The paper is devoted to estimation of profitability of biogas plants taking into account both initial stage of investment and stage of implementation. Paper has a relevant topic, which is confirmed by the literature review. However, methods of the paper do not confirm the results and conclusions. Paper does not reveal which horizon was considered to estimate profitability of the biogas plant.
1. Introduction
Authors consider different countries (Germany, Poland, India, Slovakia), but do not reveal data from which countries were applied in the practical part of research. Thus, it is not clear whether all these countries are necessary to consider.
Authors consider long run non-monetary benefits (positive externalities), but do not develop this idea through the paper in the practical part. These external benefits can be investigated for example using input-output models or via production function.
Goal and structure of the paper are omitted in this section.
2. Materials and Methods
Methods of the paper include the analytical method, complex analysis, SWOT analysis, but do not contain cost benefit analysis, which is reasonable in this case.
Data of companies is confidential, but it is reasonable to indicate affiliation of the companies.
It is recommended to explain the level of consideration. Micro approach is based on the data of the company, but macro level is grounded on SWOT analysis that has no impact on the practical part of the paper.
Methods of NPV, PI, IRR, payback period can help in decision making about profitability of biogas plant start up, but authors do not use them.
3. Results
Calculations in table 1 demonstrate the decreasing scale of biogas plant as production function, but not for 550 tons of raw material processing. Between Processing of raw materials (Y) and Amount of biogas per year (x), there is linear dependence: Y=300+50x. It means that with high probability there is a constant scale rather than decreasing one.
Through the paper there is a different interest rate of soft loan - 7% (line 268) and 9% (282).
How the proportions (line 316-325) were used in the authors' own calculations?
Depreciation technology and Depreciation building part during 15 year do not include a discount rate. Calculations in table 3 are static and do not include discount rate.
Initial costs (investment) (table 2) and maintaining/operation costs (table 3) are not connected by formulas and calculations. Authors do not demonstrate Annual profit as a function of both revenue and cost. If they use 15 years of depreciation how do they get annual profit without discounting?
SWOT analysis has to be at the beginning of the paper before calculation of annual profit. After SWOT analysis, it is reasonable to make a decision about investment in a biogas plant. There is no explanation for the purpose of SWOT analysis. It is not clear for which target audience the analysis is prepared (state or private investors).
Threats of SWOT analysis do not include decreasing natural gas price, lack of own savings for start-up investments.
4. Discussion
It is reasonable to use the real option approach to consider profitability of projects under both increasing and decreasing share/price of biogas, e.g. for different scenarios of startup investment, to be more robust in conclusions. It is also necessary to explain how to divide investment in biogas startups between state subsidy and private investments taking into account positive externalities. Input-output model can be considered to estimate indirect positive consequences of implementing biogas start-up to get state subsidies.
Technical remarks:
page 3: ‘Himshakti biogas plant project, which was to be 1-2 m square’ -> please, explain the sentence in more clear way
page 3: ‘It was also found that heat sold for crop drying processes is priced significantly lower’ -> please specify is it advantage or disadvantage for definite alternative
It is recommended for authors to revise methodology of the paper taking into account comments above.
Comments on the Quality of English Language
The paper needs to be proofread
Author Response
Thank you for reviewing our manuscript and for your recommendations. According to your suggestion, we mention in the re-submitted manuscript, the data we used is for Slovak Republic. We considered different countries in the introduction section to show the similarities and differences between different countries' approaches. The aim of the paper along with structure were added in the re-submitted manuscript. We added other methods of analyses based on your recommendations, as it can be seen in the re-submitted manuscript (all changes are highlighted). Suggested methods are added in the form of regression analysis. It was explained that SWOT analysis was used to substantiate the expediency of state support for biogas plants. Further micro-level analysis was carried out to determine the direction of state support and the subject of subsidies. An NPV analysis was carried out, and the net modern value of profit was calculated, which made it possible to draw a conclusion about the effectiveness of the investment project of a biogas plant. Thus, the NPV for 15 years of operation of the biogas plant was 1,2 million euros, which made the biogas plant a rather attractive project. It was explained that these are data from the manufacturer's website as an element of pricing for biogas plants. The different interest rate of soft loan was corrected. Discounting was also done and regression dependences of profit as a function of both income and expenses were constructed, also, the SWOT analysis was moved to the beginning of the article and an explanation was made that it is intended for the state. The principles of dividing the investment in biogas start-up between state subsidy and private investment are explained in the text. Both technical remarks have been corrected in the text of the article. Thank you again for your advice and help. Best regards, authors.
Reviewer 5 Report
Comments and Suggestions for AuthorsThe reviewed study is interesting and concerns an important issue. To improve the study, I propose a few changes.
1. The discussion should include references to other authors.
2. The study should end with a summary and conclusions, not a discussion.
3. It is advisable to provide recommendations in the summary.
4. In the text, sentences should not be ended in this way: is substantiated by [14]; were studied by [16]; proposed by [17].
Author Response
Thank you very much for your time and for your advice regarding to our manuscript. We made several changes in our paper including your suggestions. Now, discussion includes references to other authors. We also added conclusions sections and separated discussion from conclusions that now includes recommendations stemming from the research. We have also changed the ending of the sentences that ended incorrectly. Thank you once again for your help and recommendations. All changes you can find highlighted in the re-submitted manuscript. Best regards, authors.
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript incorporates the suggested comments.
Author Response
Dear Reviewer, we would like to thank you once again for your review on our article, we incorporated all suggested comments in the latest version, thank you once again, we wish you all best!
Reviewer 4 Report
Comments and Suggestions for AuthorsAuthors substantially revised their paper according to previous proposals.
Authors introduced the costs of a biogas plant in the Slovak Republic instead of an abstract country.
They improved the methodology of the paper: it was formulated with a clear goal; they replaced SWOT analysis in the beginning of the paper and added dynamic investment analysis via NPV and discounting rate.
Linear regression can explain dependence between profit and cost. However, Table 5. Regression analysis of the dependence profit on income with R-squared = 8% is not necessary to introduce in the paper, because here there is absent linear dependence.
Some new technical remarks were revealed:
page 3: At the same time. This topic -> At the same time, this topic (line 128)
page 6: least quadratic method –> ordinary least squares or OLS (line 304)
The paper can be accepted after taking into account comments above
Author Response
Dear Reviewer,
Thank you very much for your reviews, we appreciate it very much, all your comments and recommendations were incorporated in the latest version of the manuscript. We thank you once again and wish you all best!
