Advances and challenges of green hydrogen in Chile: A case study of the national strategy for a sustainable energy transition

Review
At present, the reviewer is unable to recommend the manuscript for publication. The paper requires further improvement. The points outlined below are intended to help enhance the overall quality of the manuscript.

- The abstract should be written as a single paragraph. References should not be cited in the abstract. For review articles, the study's objectives must be clearly stated. The current abstract is of insufficient quality and should be rewritten. It is recommended to consult published articles in this field within reputable journals.

- Based on the section structure, the manuscript appears to be a research article; however, based on the title, it seems to be a review paper. This issue should be clarified by the authors. If the manuscript is intended as a research article, the novelty must be clearly and comprehensively stated. However, reviewing a report alone does not appear to constitute significant novelty. Based on the content, the manuscript resembles a review study.

- The number of keywords appears excessive. It is recommended to provide a maximum of five relevant keywords.

- The introduction is currently weak. It should be strengthened and provide more substantial information. The hydrogen field has a rich body of literature; however, recent references have not been sufficiently incorporated. The introduction may also address topics such as the hydrogen market, applications, and related developments.

- The methodology section requires a more detailed explanation. At present, the descriptions appear too brief.

- The use of graphical elements could improve clarity.

- Much of the content presented in the manuscript appears superficial. The paper should be strengthened in most sections.

- It is recommended to incorporate recent and comprehensive studies throughout different sections of the manuscript.

Note:
This review refers to round 1 of peer review and may pertain to an earlier version of the document.

Review
The author presents a case study that analyses the current hydrogen strategies in Chile. The subject is of interest, and the discussion highlights meaningful topics. At the same time, I think that some aspects would benefit from an update of key figures, especially regarding the estimated production costs of hydrogen and their evolution. The global market of hydrogen and the commitments by governments and industries has changed in the last years, and I think the author should include those new insights in the analysis. At the same time, the manuscript describes in detail many opportunities, but I think that some barriers should be better described, including a discussion on the possible solutions to overcome them.

I report below my specific comments in order of appearance in the text.

Lines 57-62: The author points out the advantages of green hydrogen by mentioning the absence of carbon dioxide emissions. I think it would also worth mentioning that also blue hydrogen aims at capturing most of the emitted CO2.

Line 67-68: The renewable energy potential of 2 TW, which is a measure of capacity, could be complemented by the figure about electricity generation, in TWh, which is a better metric to evaluate the hydrogen production potential.

Line 69: The current global hydrogen demand, as of 2024, equals to 100 Mt (IEA, Global Hydrogen Review 2025), thus the Chilean potential would be two times global demand (and not three times, as mentioned in the text).

Line 76: The author reports a policy target referring to 2025. Since we are in 2025, it would be useful to include some figures about the actual capacity under development, to be compared to the expected target of 5 GW.

Lines 78-82: The production cost is not the only problem. Transportation and storage costs, especially over long distances, remain a big issue that is seldom addressed, and could represent a significant bottleneck for countries aiming at hydrogen export over long distances. This has also limited room for improvement due to the limitations of the available options in terms of energy efficiency. I think this point should also be addressed here.

Section 3.1: When addressing the global context of green hydrogen, the author should also mention the recent decrease in interest for green hydrogen, as in the last two years many governments and industries have cancelled projects and lowered targets. This should be incorporated in this section. In a similar perspective, although Chile has some advantages, that are mentioned by the author, it also has some disadvantages, such as the distance from potential markets, requiring long-distance transport via ships, that could represent a barrier given the higher costs. I think an objective description should include both advantages and disadvantages, opportunities and barriers.

Lines 154-155: The figures mentioned here are from a 2020 study, and they may be outdated and no longer relevant. Given the current evolution of the hydrogen market, a production cost of 1 USD/kg by 2030 seems rather unrealistic. I recommend the author to look for more updated figures here. The same applies to this value reported in Table 1.

Lines 252-253: These figures on production cost are different from those mentioned earlier in the paper (lines 79-80). Please justify this difference.

Lines 291-294: The estimates mentioned here (reference [28]) refer to 2020 (thus likely including even earlier data). The author should look for more recent estimates given the significant variations in the hydrogen market in the last years.

Some barriers and limitations are mentioned in the conclusions but not earlier in the text. I think a better description of the barriers could add significant value to the analysis, by discussing potential solutions that could be deployed to overcome them.

Note:
This review refers to round 1 of peer review and may pertain to an earlier version of the document.