Scientometric Analysis of Energy Efficiency Indicators in Maritime Transportation: A Systematic State-of-the-Art Review and Implications
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe paper is a systematic literature review on a very hot and relevant issue for the shipping industry which is the energy efficiency of the ships and the IMO’s measures to improve it with specific measures and indicators. The literature on the subject is very rich. The paper collects and discusses 192 studies which I believe is an adequate number to cover all the aspects of the subject. The data bases used are the esteemed WoS and Scopus, both containing peer reviewed scientific information.
The results are mostly provided in an aggregated form, since it would be difficult to focus on each one of the individual studies. An interesting question that arises is the efficiency of the measures - indixes and the degree that the GHG or CO2 emissions have decreased today compared to 15 years ago, before the introduction of the measures. The IMO’s GHG studies and the aggregated results of the DCS could be used as sources for this estimation.
Some remarks follow to improve the paper follow. Please also check carefully thought out the paper for minor comments.
- 1, L.16: The fundamental energy efficiency measures must be introduced in a logical order. I suggest a chronological order.
- 1. L. 20 : “introduced by IMO in 2010”: Please change to “introduced by IMO in 2010 and successively amended till today”
- General comment: Please mention in the introduction that that EEOI is not a mandatory index (the other indexes are mandatory). It is a voluntary indicator suggested by the IMO to monitor the energy efficiency performance of a ship in SEEMP Part I.
- General comment: SEEMP with its 3 parts is not an indicator but a document onboard encompassing several indicators (DCS, CII). Please make this distinction in the beginning of your text. I suggest keeping it in your analysis but do not refer to SEEMP as an indicator because it is not.
- In the methodology section, please refer to the period (years) you have selected for the literature review.
- 2, L. 54: greenhouse gas (GHG). Please add the acronyms the first time that the term appears in the body (not the abstract) of the paper.
- , L.80: Energy Efficiency Operational Indicator (EEOI) is not mandatory, it is voluntary, so we cannot say “it came into effect”.
- 3, L.111. “𝑷 is the energy generated by the main engine in kWh”. Actually, P is the power of the engine in kW!!!!!! Please correct accordingly.
- 3, L. 125: “Energy Efficiency Existing Index”. Change it to “Energy Efficiency Existing Ship Index”.
- 11, L. 288. Please give more countries that appear with 1-2 papers. Explain why research is conducted in the specific countries. Do they have specific maritime interests? Are they economies based on maritime trade? Or are they countries with high scientific level and production? Interestingly, USA do not appear in your data. Any explanation?
- 18, L. 328. “a total of 345 indicators” or 368 indicators? Please explain.
- 19, L. 346. “Figure 9. Indicator calculation numbers”. The two numbers in this figure do not worth a figure. They could just be mentioned in the text.
- 19, L. 353. “Figure 10. Calculated indicator distribution”. As mentioned in comment 4, SEEMP is not an indicator to be calculated. In my opinion should not be included in Figure 10.
- 23, l. 51-52. “All mentioned indicators set by IMO have been used for operating sustainable and green maritime transportation globally”. I would suggest “All mentioned indicators set by IMO have been used for design, constructing and operating sustainable and green maritime transportation globally”.
Comments for author File: 
Comments.pdf
Author Response
Many thanks to reviewer for the valuable comments. All the answers were given in the attached file.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsDear authors
Your manuscript, "Scientometric Analysis of Energy Efficiency Indicators in Maritime Transportation: A Systematic State-of-the-Art Review and Implications,” has valuable ideas. Still, I prefer to provide some recommendations that are not mandatory to be applied, but they help to provide better quality for your manuscript. These are as follows:
1. The abstract is well written but short; try not to use many abbreviations in the abstract, which is not formal, and also explain more about the study's outcome.
2. I believe keywords require revisions; try to use logical keywords.
3. Please provide suitable paragraphing. Each paragraph must be 4-8 lines, depending on the text and context. This is necessary for a scientific text.
4. Please provide suitable-sized images and figures in the manuscript. For example, you can decrease the size of 1,5, 6,7, 8, and even 11. In this regard, you help the reader and reviewer, too, and provide a positive impact while drastically decreasing the number of pages of your manuscript.
5. In the PRISMA flowchart, you show the total number of references is 192, but in reality, it is 225; how do you explain this issue?
6. All expressions with abbreviations must only be mentioned first and then only abbreviations; follow these issues. Otherwise, the reviewer thinks you have provided your ENTIRE manuscript with AI.
7. I think the manuscript needs a " discussion " section that discusses all the findings you tabulate and explain in section 4; otherwise, only tabulating and analyzing in different forms cannot help and sound scientific.
8. Using many bullet points in conclusion is not common.
9. In conclusion, please clearly explain the three main issues, the study's main outcome, your limitations when preparing this research or collecting information, and recommendations for future studies in the relevant field.
10. Finally, I want to express that it's not a bad issue to use AI to provide a manuscript, but you have to categorize the information, insert your idea to humanize the manuscript, and insert your signature on it. I hope to understand the point and try to provide it in the next round; otherwise, it does not have a suitable scientific sound in this style.
Thanks for your attention.
Author Response
Many thanks to reviewer for the valuable comments. All the answers were given in the attached file.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for Authors- The abstract contains redundant and repetitive phrases; it is recommended to refine the wording to enhance professionalism and readability.
2. Some terms are used imprecisely—for example, "stop climate change" does not align with the current academic consensus.
3. The abstract lacks smooth transitions between elements; improving the logical flow is advised.
4. The description of the research method in the abstract is insufficiently detailed; adding specifics about the PRISMA process and analysis indicators would strengthen the methodology section
5. Most of the figures contain excessive blank space, which unnecessarily occupies valuable manuscript space and negatively affects the overall layout. It is recommended to revise the figures to optimize space utilization and improve visual balance.
6. Please add relevant references to support the statements and enhance the academic rigor of the manuscript, such as:
Atomization and Sprays, 2025，35(1): 19-45； Applied Thermal Engineering,2025， 263, 125391；Experimental Thermal and Fluid Science, 2024，163: 111403 DOI
10.1016/j.expthermflusci.2024.111403
- Figure 11 appears disorganized and lacks a clear structure, making it difficult for readers to interpret the information effectively. It is recommended to reorganize the figure to enhance clarity and visual coherence.
- The abstract contains redundant and repetitive phrases; it is recommended to refine the wording to enhance professionalism and readability.
2. Some terms are used imprecisely—for example, "stop climate change" does not align with the current academic consensus.
3. The abstract lacks smooth transitions between elements; improving the logical flow is advised.
4. The description of the research method in the abstract is insufficiently detailed; adding specifics about the PRISMA process and analysis indicators would strengthen the methodology section
5. Most of the figures contain excessive blank space, which unnecessarily occupies valuable manuscript space and negatively affects the overall layout. It is recommended to revise the figures to optimize space utilization and improve visual balance.
6. Please add relevant references to support the statements and enhance the academic rigor of the manuscript, such as:
Atomization and Sprays, 2025，35(1): 19-45； Applied Thermal Engineering,2025， 263, 125391；Experimental Thermal and Fluid Science, 2024，163: 111403 DOI
10.1016/j.expthermflusci.2024.111403
- Figure 11 appears disorganized and lacks a clear structure, making it difficult for readers to interpret the information effectively. It is recommended to reorganize the figure to enhance clarity and visual coherence.
Author Response
Many thanks to reviewer for the valuable comments. All the answers were given in the attached file.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsDear authors
Your revised manuscript, "Scientometric Analysis of Energy Efficiency Indicators in Maritime Transportation: A Systematic State-of-the-Art Review and Implications,” has greatly improved and has valuable ideas. Still, I prefer to provide some recommendations that are not mandatory to be applied, but they help to provide better quality for your manuscript. These are as follows:
1. The abstract is well written but is longer than standard and is around 330 words!!!!!!!!; try to manage it within the limitations.
2. Plz relocate all references at the end of sentences.
3. Please adjust the length of paragraphs to be suitable, between 4 and 8 lines depending on the text and context; in this way, you help the viewer read carefully, not get bored, and follow the context.
Thanks for your attention.
Author Response
Many thanks to reviewer for the valuable comments. All the answers were given in the attached file.
Author Response File: Author Response.pdf
