A Techno-Economic Study for Off-Grid Green Hydrogen Production Plants: The Case of Chile

Round 1

Reviewer 1 Report

Title:

Please edit the title. It must be “an off-grid.”

Abstract:

 

1. Methods: The methods are concisely outlined, although further clarification would help. For example, how did you calculate the manufacturing and product costs? How did you decide on the base case production?
2. Results: The results are briefly summarized. Including some comparative context (e.g., how these costs compare with similar projects or with conventional hydrogen production) could be helpful to readers.
3. Context and Implications: The abstract could benefit from an additional sentence or two at the end that describes the implications of this research and its broader impact.
4. General recommendation: Since an abstract is the first part of the paper a reader encounters, briefly mentioning why Chile was chosen for this study would be beneficial. This would add context and capture the reader's interest more effectively.

 

Keywords:

1.     The authors can add “green hydrogen” to the keywords.

1. Introduction:

1.     The introduction needs a comprehensive literature review. The authors are advised to appropriately cite relevant studies on green hydrogen production to enrich the context of their work. Given the extensive number of publications that cover various aspects of green hydrogen production and utilization, a critical discussion of this literature is necessary. Furthermore, the authors should clearly articulate the novelties of their study, highlighting how it contributes uniquely to the existing body of knowledge.

 

2. Materials and Methods

 

1. Data Sources: References to data sources are provided, which is good. However, the authors should also provide some justification for selecting these data sources to strengthen their credibility.
2. Assumptions: The assumptions made in this study, such as the CAPEX, OPEX, capacity factors for solar and wind energy, and desalination plant costs, are explicitly stated. This transparency helps readers understand the framework within which the study operates.
3. Reproducibility: The authors have provided enough details for the study to be replicated, which is commendable.
4. Novelty and Impact: While the authors mention choosing Chile for its potential for solar and wind energy, it might be beneficial to include a statement in this section about the novelty of this study, perhaps regarding its approach, methodology, or application to the specific regions in Chile.
5. Language: The text is mainly well-written. Some sentences are long and might benefit from simplification for clarity. Consider breaking down complex sentences and reducing the use of passive voice.
6. General recommendation: It would benefit the authors to acknowledge any possible limitations or weaknesses in their methodology. This will provide a more proper perspective and strengthen the credibility of their study.

 

3. and 4 Results and Discussion

1. The structure of the Results section requires attention. The initial portion (section 3.1.) is more methodological than presenting actual results. I recommend relocating this subsection to the Materials and Methods section (section 2) to maintain a logical flow and consistency in the manuscript.
2. The data presented in the tables and figures within the Results and Discussion section requires further elaboration. Please thoroughly explain the key findings from these visuals to enhance reader comprehension. This could include emphasizing significant values, trends, or patterns and clarifying what they imply in the context of your study.
3. The manuscript currently lacks a validation or comparison of the results obtained. It is imperative to validate the findings and articulate their reliability to readers. The authors could achieve this by comparing their results with those from similar studies in the field or by using statistical analysis to confirm the significance of the findings. This step would significantly enhance the study's credibility and contribution to the field.

 

5. Conclusions

1. Potential Implications: It would be beneficial to elaborate on the potential implications of this research beyond the feasibility of green hydrogen production in Chile, such as how it could impact the global hydrogen market, the renewable energy industry, or climate change efforts.
2. Future Directions: Lastly, the authors might consider stating more explicitly potential future directions or next steps following this research. This could include suggestions for further studies to confirm these results or investigations into other possible factors affecting green hydrogen production in Chile or similar locations.

 

The manuscript is generally well-written. However, the authors can edit its language during the revision. Please take a look at my specific comments on the language above.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

This study focuses on a comprehensive evaluation of analyses for green hydrogen production plants to investigate the production costs of the hydrogen production industry. The findings will provide valuable insights into other industrial processes, such as CO2 utilization. The study is well-organized and presented, making it suitable for publication in this journal. However, some improvements are needed in the figures since they are not very clear.

The writing is well understood. 

Author Response

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Reviewer 3 Report

Dear Editor,

I have completed reviewing this article (energies-2463321) which needs major revision.

Title: Techno-Economic Study for a Off-Grid Green Hydrogen Production Plant: The Case of Chile

Suggestion: Major revision

 

This article incorporated a comprehensive financial analysis from the perspective of the project initiators, determining the profitability of the project using economic indicators such as the net present value (NPV). Accordingly, the authors encompassed the sizing of the alkaline electrolyzer stack, the seawater desalination system, and the solar and wind renewable energy farm. It is a very meaningful paper which gives the public some guidances when starting to make some policies on off-grid green hydrogen production Plant. It is well-organized and designed. My overall feeling towards this manuscript is positive. Analysis is also appropriate and seems properly implemented. However, there are some major issues that need to be addressed.

 

1. Abstract. What is the limitation of the existing studies? The authors need to explore the originality and contribution of the study in this section. 

 

2. The authors should provide a paragraph at the end of the Introduction section to present the article organization.

 

3. The literature section is missed; Although the authors have classified the existing literature in Introduction section, I still think a literature review section is necessary. How the existing studies related to your methods? These issues should be stated clearly in this section.

 

4. The data source should be stated more clearly, and how the authors pre-process the null data? 

 

5. How could the authors solve the robustness problem in the model? The authors should state it clearly.

 

6. The discussion section is missed. What implications could be drawn from the results? The current discussions are separated from your results.

 

7. The policy recommendations are missed; the authors should focus on your results, or the recommendations should be drawn from your results directly.

 

 

8. The limitations or future research directions should be presented in a new subsection.

Minor editing of English language required

Author Response

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Reviewer 4 Report

 

1. Where is equation 4? I could not find it in the manuscript.
2. What do numbers (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), and (11) mean (given in  in Table 1)? What do (+), (-), and (=)  in Table 1 mean? Some explanation should be given in notes or in the manuscript text.
3. Why is the assumed cost of the alkaline electrolyzer just 270 USD/MW? Why is it so low?
4. From which source are these values (see line 245)? Why for wind energy it is lower than that for PV?
5. From my point of view, the following or similar information must be mentioned in line 251: “Conversion rate of water is unity, which means that 100% of water is converted/decomposed into hydrogen and oxygen.”
6. No information is given about the rate of oxygen production (see lines 253 and 254).
7. Tables 2, 3, 4, and 5 are not mentioned in the main body of the text! Some explanation of the content of those tables should be presented.
8. What is the name of column 3 in Tables 2, 3, 4, and 5?

Author Response

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Round 2

Reviewer 1 Report

The authors appropriately revised the manuscript.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

I think this manuscript could be considered for publication in present form.

Author Response

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Reviewer 4 Report

Remarks of Reviewer 4 to the cover letter (4) and revised version (v2):

 

The “Response to Reviewer 4 Comments” is disappointing. In particular, the responses to points 2, 3, 4, and 8. Therefore, the authors are asked to comply with the remarks provided below.

 

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1. Regarding point 2 (of the Response…):

 

My previous remark:

“What do numbers (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), and (11) mean (given in Table 1)? What do (+), (-), and (=)  in Table 1 mean? Some explanation should be given in notes or in the manuscript text.”

 

The Authors’ response is thoroughly unsatisfactory (one sentence that doesn't explain anything). The table must be clarified to the reader in the text!!!

Some of the ambiguities are given below the table.

 

 

The ambiguities (examples):

 

The row 4: Income before tax = (1) Income(sales) – (2) OPEX – (3) Depreciation – (4) Income before tax??? Looks like nonsense, or explain it.

The same is about rows 5, 6, and 9.

 

The row 9: What are (10) and (11)?

 

What is the difference between row 1 Depreciation and row7 Depreciation?

 

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The same remarks as for Table 1 pertain to Table 6 and 7! 

 

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Conclusion: I cannot accept this manuscript for publication without fully and clearly explaining Tables 1, 6 and 7 to the reader in the manuscript text.

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2. Regarding point 3:

See: Revised version (v2), see lines 294/295, 356/367, 361/362 - -  the cost of electrolyzer of 270 USD/MW

 

It is astonishing that the assumed cost of an alkaline electrolyser is 270 USD/MW.

See:

A)

Ref. [23], https://irena.org/-/media/Files/IRENA/Agency/Publication/2020/Dec/IRENA_Green_hydrogen_cost_2020.pdf Page 66

 

Capital     costs minimum 1 MW	(stack)	USD 270/kW !!!!!!!!	< USD 100/kW	Electrodes
Capital   costs minimum 10 MW	(system)	USD 500-1 000/kW	< USD 200/kW	Balance of plant

 

B)

The lab-scale 400 W alkaline electrolyser costs 979 PLN (around 249 USD):

https://www.amazon.pl/IPOT-rozdzielacz-gospodarstwa-laboratoryjne-eksperymentalne/dp/B09HWTZNZP/ref=asc_df_B09HWTZNZP/?tag=plshogostdde-21&linkCode=df0&hvadid=542262054373&hvpos=&hvnetw=g&hvrand=6614302978048731188&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9067400&hvtargid=pla-1532428147574&psc=1

 

This matter must be thoroughly and unambiguously verified. All the calculations and conclusions derived by the Authors are based on the assumed cost of an alkaline electrolyser of 270 USD/MW. However, this value seems to be understated about 1000 times !!!! If so, the results of this work are highly questionable.

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3. Regarding point 4:

Please, explain clearly this point to the reader in the text. What is “a lower plant factor?”.

 

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4. Regarding point 8:

My previous remark:

“What is the name of column 3 in Tables 2, 3, 4, and 5?’

 

Once more, please explain clearly the meaning of the above mentioned column to the reader in the text.

 

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Comments for author File: Comments.docx

Author Response

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Round 3

Reviewer 4 Report

Accepted