Review Reports - Evaluating the Use of Alternative Fuels in Cement Production for Environmental Sustainability

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript presents an important empirical study exploring how alternative fuels (AFs) including biomass, refuse-derived fuels (RDF), and sewage sludge can significantly reduce CO₂ emissions in the UAE cement industry. Through statistical analyses of real-world secondary data and regression modeling, the study affirms that a 30% AF substitution can lead to a substantial drop in emissions, especially when supported by economic incentives and technological integration. Given the high carbon footprint of cement production and the UAE's commitments under the Green Agenda 2030, these findings are highly relevant. The paper makes valuable contributions to sustainable development literature and offers practical guidance for policy and industrial implementation. However, revisions are needed to improve clarity, rigor, and coherence.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

The English could be improved to more clearly express the research.

Author Response

Dear Sir, I am attaching the reply to address the concerns for your consideration. Please review the changes in the relevant section of the article.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Despite the relatively high popularity of the topic among researchers in relation to CO₂ emission reduction issues, the presented manuscript may be relevant and of interest to both researchers and practitioners. The authors explore the possibility of replacing traditional fuels with alternative fuels for furnaces used in the cement industry in the UAE.

The inverse correlation between the share of alternative fuels and CO₂ emissions (r = -0.82) obtained by the authors in the course of their research indicates the relevance of introducing alternative fuels, especially with the support of new technologies. Thus, according to the authors, the efficiency of alternative fuels in cement industry furnaces in terms of CO₂ emissions reduction can reach up to 83 %.

In the introduction, the authors clearly formulated the problem that this study aims to solve. The focus on the circular economy provides additional relevance. The proposals made by the authors are consistent with the objectives set, and the hypotheses they describe are largely justified.

The methodology description is acceptable. The authors' use of secondary data, but the reproducibility of the research results requires further clarification.

The authors use a regression model in their study to search for a link with CO₂, omitting important details about testing for multicollinearity and model sensitivity, which also require further clarification.

Below are comments recommended to the authors for correction in order to improve reproducibility and reader confidence in the results presented by the authors.

Major issues

Please provide a description of the data collection and validation processes.
Consider adding additional variables (production volume and energy efficiency) to the regression model. Without this, it will be difficult for the reader to be sure that alternative fuels are indeed the cause of CO₂ emissions.

Minor issues

(line 47) "has a considerable role in air pollution." Please rephrase this statement, as CO₂ itself is not considered a traditional air pollutant.
(lines 48-49) "to cut cement emissions by 16% up to 2030." The authors are advised to check whether the Paris Agreement indeed contains specific commitments to reduce CO₂ emissions in the cement industry.
(line 56) "and necessitates urgent interventions." Avoiding emotional and categorical wording is recommended. Facts will be perceived more convincingly by the reader if they are substantiated and confirmed by specific empirical data. The authors are advised to check all emotional statements.
(lines 99-100) "however, the integration of these alternatives has the potential to circumvent the anthropogenic CO₂ emission by up to 40% by 2030." The authors make a very ambitious claim. It is recommended to check whether the sources cited by the authors (Bianchi et al., 2021; Elbaek et al., 2021) actually contain information about a 40% reduction in CO₂ emissions in the cement industry by 2030.
Consider shortening the description of the problem by avoiding the repetition of facts and motivations already mentioned in the introduction.
Support your conclusions with either numerical data obtained from your research or references to reliable sources. Despite the presence of a separate paragraph, provide the reader with information on how the limitations affect your conclusions.
Consider adding additional citations to existing research on the topic that is relevant outside the EU, particularly in relation to the UAE.
Figure 1 needs further development. The description in its current form does not provide useful information to the reader.

Overall, the work is relevant to the journal's subject matter and, after revision of the methodology and verification of empirical sources, is recommended for consideration for publication.

Author Response

Dear Sir,

I am attaching a point-by-point response and changes made to all the concerns put on our article

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript focuses on evaluating the use of alternative fuels in cement production for environmental sustainability. I think it can be considered for possible publication in the journal after a minor revision. Some recommendations are as following:

The author should reflect the research background and purpose in the article. Please supplement it by referring to the following literature 10.1016/j.jclepro.2022.131527.
The term "CO2" in the text should be modified to "CO₂".
In line 149, the purpose of this study is to demonstrate that 'AFs adoption in the cement industry significantly reduces the emission of CO2 to the environment'. Please explain the scientific basis for H1 as a hypothesis.
Please check the spelling and grammar errors in the text, for example, in line 279, "0r" should be "or"
Please use the formula editor to edit the formula in line 312.
Give an example of how to calculate β0, β1, β2, β3.
Please discuss the optimal AF.
Please improve the clarity of Figure 1.
Please supplement the comparison with existing research results in the article, highlighting the research value of this paper.
Simplify the conclusion and highlight the innovative points of this article.

Author Response

Sir,

I am attaching the rebuttal letter, author response, and changes made in the manuscript for your consideration

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Authors have addressed all of my comments, and the manuscript has been sufficiently improved to warrant publication in Sustainability

Author Response

The authors appreciate the insightful comments provided by the respected reviewer and have thoughtfully revised the manuscript following the suggestions. These improvements have further strengthened the clarity, relevance, and overall quality of the work. All these changes are highlighted in the article text.

S.No	Specific Comments for Revisions/ Reviewer 01	Authors Responses
1	[Lines 102–103]- The sentence “key developments in kiln technology…are nuts and bolts” uses informal language. Consider rephrasing to: “are essential for enabling efficient utilization of alternative fuels.”	[Lines 102–104]- Rephrased
2	[Lines 133–135]- The purpose of the study is stated broadly. Please sharpen the research objectives and ensure they align clearly with the hypotheses (Lines 148–154).	[Lines 132–138]- Objective re-write and set on SMART criteria/Also aligned with R.Hypothesis
3	[Lines 214–217]- The statement on carbon capture reducing 50–90% of CO₂ emissions is valuable. However, clarify whether these results were from real industrial plants or only pilot-scale studies.	[Lines 205–207]- Rephrased as the references were weak
4	Section 3: The “Results” section does not properly reflect the main results. Change the subtitles 3.1, 3.2, 3.3, and 3.4, and directly highlight your results. For example, “3.3 Relationship Between AF Adoption and CO2 Emission”, and so on.	[Lines 256–263, 276-278, and 301-303]- Corrected all sections as per the reviewer's suggestion
5	[Lines 269–270]- Table 1 is introduced, but there is no reference to the sample size (n =?). Please add the number of observations for each variable.	[Lines 270–271]- Observation for each variable added
6	[Lines 312–313]- The regression model equation should follow consistent notation. Use italics for variables (e.g., CO₂ = β₀ + β₁AF + β₂INC + β₃TECH + ε).	[Lines 314]- the variables were converted to italics
7	[Lines 368–369]- The conversion from 0.195 kg/kg clinker to 21.7% reduction lacks explanation. Please clarify the basis for this percentage or provide step-by-step logic.	[table 3, Lines 394-400]-Changed to metric tons
8	[Lines 471–474]- The limitation related to “upstream emissions from AFs” is critical but underdeveloped. Expand this section to explain how upstream emissions (e.g., from the collection or processing of AFs) could affect overall sustainability outcomes.	[Lines 515–527]- Limitations of the research changed as per the other reviewer’s suggestion
9	The paper frequently uses acronyms (e.g., AFs, CCS, RDF) without immediately defining them. Define all acronyms at first use for clarity.	Changed throughout the text
10	Although the introduction presents the environmental issues well, it should more clearly state the research gap this study addresses, especially in the context of the UAE.	[Lines 161-169]- the section added
11	The hypotheses are stated clearly but could be made more testable by specifying expected directions (e.g., "AF adoption will significantly decrease CO₂ emissions by more than X%").	[Lines 140-145]- Rephrased
12	Across tables and discussions, use consistent units (e.g., kg CO₂/kg clinker vs. metric tons). Inconsistent units may confuse readers or lead to misinterpretation.	Changed to metric tons in all text
13	The abstract would benefit from including specific results (e.g., “R² = 0.83, p < 0.001”) to give readers immediate insight into the strength of your findings.	[Lines 28]- (R² = 0.83, p < 0.001) value added
14	The paper discusses subsidies and carbon pricing but lacks international comparisons. Add a short section comparing the UAE’s readiness to adopt these tools with other regions (e.g., EU, China).	[Lines 429-444]- A section is added with the heading “Subsidies and Carbon Pricing Comparison”

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

In the revised version, the authors have taken into account the reviewer's comments, including the description of the collection and validation of data used in this study. In section 2.4, the authors refer to the fact that they used a multi-stage protocol. Although the authors' description of this issue is consistent with acceptable practices for disclosing information on data collection and validation, the manuscript would benefit significantly and generate greater interest among readers if the authors could present the protocols they used in an appendix.

The methodology of the authors' research in its current form is described in a reproducible manner, and the comment regarding the regression model has been taken into account.

Overall, this study, with its focus on the circular economy, may be of interest to readers, as it addresses the topical issue of decarbonization in the cement industry.

Recommended for publication, and the editors are encouraged to ask the authors to back up this study with a more detailed description of the protocols they used.

Author Response

Reviewer 02

S.No	Specific Comments for Revisions/ Reviewer 02	Authors Responses
Major Revisions	Please provide a description of the data collection and validation processes.	[Lines 222-234]- Sub-section added
Major Revisions	Consider adding additional variables (production volume and energy efficiency) to the regression model. Without this, it will be difficult for the reader to be sure that alternative fuels are indeed the cause of CO2 emissions.	[Lines 349-363]- Expanded Regression Analysis and Table 4
1	(line 47) "has a considerable role in air pollution." Please rephrase this statement, as CO2 itself is not considered a traditional air pollutant.	[Lines 47-49]- Rephrased
2	(lines 48-49) "to cut cement emissions by 16% up to 2030." The authors are advised to check whether the Paris Agreement indeed contains specific commitments to reduce CO2 emissions in the cement industry.	[Lines 47-49]- Rephrased
3	(line 56) "and necessitates urgent interventions." Avoiding emotional and categorical wording is recommended. Facts will be perceived more convincingly by the reader if they are substantiated and confirmed by specific empirical data. The authors are advised to check all emotional statements.	[Lines 54-57]- Rephrased
4	(lines 99-100) "However, the integration of these alternatives has the potential to circumvent the anthropogenic CO2 emission by up to 40% by 2030." The authors make a very ambitious claim. It is recommended to check whether the sources cited by the authors (Bianchi et al., 2021; Elbaek et al., 2021) contain information about a 40% reduction in CO2 emissions in the cement industry by 2030.	[Lines 102-104]- Rephrased and cited accordingly/the previous citations removed
5	Consider shortening the description of the problem by avoiding the repetition of facts and motivations already mentioned in the introduction.	[Lines 121-130]- The problem statement is shortened to the points
6	Support your conclusions with either numerical data obtained from your research or references to reliable sources. Despite the presence of a separate paragraph, provide the reader with information on how the limitations affect your conclusions.	Numerical data is added from this research.
7	Consider adding additional citations to existing research on the topic that is relevant outside the EU, particularly in relation to the UAE.	Added more than 10 latest references
8	Figure 1 needs further development. The description in its current form does not provide useful information to the reader.	[Lines 381-392]- The model changed but the variables remain the same Description added to the conceptual model of the research

Reviewer 03

S.No	Specific Comments for Revisions/ Reviewer 03	Authors Responses
1	The author should reflect the research background and purpose of the article. Please supplement it by referring to the following literature 10.1016/j.jclepro.2022.131527.	[Lines 67-69]. Supplemented with this source
2	The term "CO2" in the text should be modified to "CO2".	Changed in the entire text
3	In line 149, the purpose of this study is to demonstrate that 'AFs adoption in the cement industry significantly reduces the emission of CO2 to the environment'. Please explain the scientific basis for H1 as a hypothesis.	[Lines 133-134]- Rephrased as per suggestions
4	Please check the spelling and grammar errors in the text, for example, in line 279, "0r" should be "or"	All grammatical and spelling mistakes removed
5	Please use the formula editor to edit the formula in line 312.	[Lines 314]- Edited
6	Give an example of how to calculate β0, β1, β2, β3.	[Line 335-341]- Example added
7	Please discuss the optimal AF.	[Line 311-312]-
8	Please improve the clarity of Figure 1.	[Line 381-392]- Elaborated
9	Please supplement the comparison with existing research results in the article, highlighting the research value of this paper.	[Line 528-538]-A section added to the article with “Research Value of the Study”
10	Simplify the conclusion and highlight the innovative points of this article.	Improved

Author Response File: Author Response.docx