Carbon Footprint Assessment of Hydrogen and Steel

Round 1

Reviewer 1 Report

The authors are advised to correct the following points before re-submission:

1. Revise the abstract and show the novelty of the paper.

2. Redraw figures (1) and (8) to show more clarity. The quality is very poor. Use specific drawing tools.

3. Add the challenges of hydrogen production and storage. Also, add future perspectives of the study on the basis of present challenges or case studies.

4. Section 3.2- Life cycle inventory is not up to the mark.  Expand it.

5. Use the taxonomy of the study in the literature review section. 

 6. Reduce the repeatability contents in the manuscript and also correct the grammatical mistakes.

Author Response

Dear Reviewer,

Thank you very much for your help to improve the paper. Please, find attached our responses to your comments.

Best regards

Author Response File: Author Response.docx

Reviewer 2 Report

Dear Authors,

The research in the article "Carbon footprint assessment of hydrogen and related hydrogen-based steel production" assesses and the carbon footprint of steel production via direct reduction unit and an electric arc furnace, whereby the direct reduction with natural gas and with hydrogen are compared with each other.

Abstract is written correctly. Introduction provides sufficient background with relevant references. The choice of the Life Cycle Assessment (LCA) method has been appropriate. This method enables in a modern way the evaluation and comparison of the different production systems and assesses their impact on the environment throughout the entire life cycle of the products. The description of the methodology is detailed and correct. The results are presented in a clear and legible way. Conclusions are written correctly. Minor revision is recommended to improve the quality of the article.

The following comments are for the authors to consider:

Line 16,19,62…: Please change ”CO₂eq” to ”CO₂ eq.”

Line 23: In keywords, I suggest avoiding the duplication of words already in the article’s title, e.g. ‘’Carbon footprint assessment”.

Line 28: I suggest providing abbreviation for “the European Commission”. Abbreviation should be defined the first time it appears in each of three sections: the abstract; the main text; the first figure or table. When defined for the first time, the abbreviation should be added in parentheses after the written-out form.

Line 77: I suggest providing abbreviation for “the European Union”

Line 77: Please change “Million” to “million”

Line 382:  “figure 6” without bolding

Lines 590-674: Please check the requirements of the journal for references formatting.

Author Response

Dear Reviewer,

thank you very much for your help to improve the paper. Please find attached our responses to your comments.

Best regards

Author Response File: Author Response.docx

Reviewer 3 Report

I'd consider rephrashing the following part of the sentence: "steel is firmly established within the human lifestyle..", as well as the use of "the" at the beginning of certain sentences (ie.: the steel industry). 

In my opinion, the abstract of the paper could be improved by being written in a more flowing style and the methodology of the study should have been pointed out. 

Author Response

Dear Reviewer,

thank you very much for your help to improve the paper. Please find attached our responses to your comments.

Best regards

Author Response File: Author Response.docx