Optimized Expansion Strategy for a Hydrogen Pipe Network in the Port of Rotterdam with Compound Real Options Analysis

Round 1

Reviewer 1 Report

General comments:

1. Formulation of the title

The title of the article corresponds to the aim and results of the research.

2. The importance and usefulness of the research

The topic is important due to the fact that Global warming driven by human-induced emissions of greenhouse gases imposes severe threats to ecosystems and especially to densely populated urban deltas which are prone to flooding.

3. Originality and novelty

The novelty of the paper is reflected in application of Real Options Analysis (ROA) to find the optimal expansion strategy for a hydrogen pipeline network in the port of Rotterdam under uncertain demand development.

4. Scientific quality

The scientific quality is good since it presents a unique perspective on a compound real choices method in which the best strategic path is the primary outcome. Hydrogen is thought to be a promising energy carrier. The study looks into decision-making in the face of ambiguity and emphasizes flexibility. Simultaneously, the real options approach gives a levelized unit pricing for hydrogen distribution.

5. The style of expression

The paper is clearly written and accessible. The arguments are presented concisely and logically. Spelling and punctuation are respected. The graphic presentation of the work is excellent.

6. Use of References

The bibliographic references represent the paper's main point; citations are from peer-reviewed journals around the world. References from recent issues of relevant journals are used.

Additional comments:

I suggest to the authors to provide, if possible, research on the impact on the economy, society and the environment in the port area of Rotterdam, as a result of the expansion strategies with a hydrogen pipeline network.

Author Response

Thank you very much. Please see the attachment for our response.

Author Response File: Author Response.pdf

Reviewer 2 Report

This paper is well written manuscript for hydrogen pipe network investment at Rotterdam port. The methodological approach is sound and inferences are strong. Yet the paper requires a revision to improve exposition and better clarify some aspects by addressing all of following comments:

1- Introduction of this manuscript is missing a section about novel energy management concept for ports. The introduction gives a lot of focus on ROA, but it would be better if authors give background information (in introduction beginning) on clean port energy management system, increasing importance of energy management in ports, and energy networks around the ports with some literature analysis. 

Following studies focus on clean energy management at ports. I think all of the following papers can be cited and discussed extensively in the introduction:

-A review of energy efficiency in ports: Operational strategies, technologies and energy management systems. Renewable and Sustainable Energy Reviews, 112, pp.170-182, 2019.

-Energy management in seaports: A new role for port authorities. Energy Policy, 71, pp.4-12, 2014.

-Optimal energy management and operations planning in seaports with smart grid while harnessing renewable energy under uncertainty. Omega, 103, p.102445, 2021.

-Day-Ahead Optimal Economic Dispatching of Integrated Port Energy Systems Considering Hydrogen. IEEE Transactions on Industry Applications, 2021.

2- The contributions of this work are not well discussed in the introduction. They should be better clarified and explained.

3- The specific research gap addressed by this work should be clarified in the introduction. Currently research gap is vague and unclear. The introduction is written in a very general way, mainly for methodology. The content should be more improved.

4- On line 154, the number and composition of respondents to produce Table 1 should be better explained.

5- It is not so clear how hydrogen will be used. Is it for the use of Rotterdam port (such as hydrogen  vehicles) or is it to supply ships which will be fueled by hydrogen or is it for transporting hydrogen by ships to overseas? These aspects should be better explained in section 2.

6- Figure 1 can be better explained. The meaning of each node and stages can be better explained.

From the tree, it is not clear what are the decisions and what the chance events in each stage. This can be better presented.

7- Line 200-204, what do () refer? 

8- An illustrative example can be added to better explain the optimal path determination.

 

 

Author Response

Thank you very much. Please see the attachment for our response. 

Author Response File: Author Response.pdf

Reviewer 3 Report

Paper 1303831 review to Sustainability – Optimized expansion strategy for a hydrogen pipe network in the port of Rotterdam with compound real options analysis.

 

All issues raised in this review can be considered to be minor reviews.

 

General considerations

The subject of this article is very relevant and current. The article is extremely well prepared, with a high quality content approach, which is explained very clearly and with the fundamentals and ideas very well-articulated, and can be well understood even by readers who may not even belong to this area of knowledge. The issue of sustainability is present throughout the article, namely through the framework presented with the issues of economic sustainability of the project over time.

Article structure

The structure of the article is well elaborated, with no flaws detected in the numbering of the sections (chapters) presented, as well as in the subtitle numeration of figures, tables and equations.

Title, Abstract and Keywords

• The title is appropriate and succinct, allowing immediately to understand the purpose of the paper.
• The abstract is well constructed. The main research question, the objectives and the framework of the theme are clearly pointed out. But, perhaps two lines should be added with the most impactful conclusions of this research work.
• The keywords are appropriate.

Affiliation

Affiliations seem to be correct in terms of numeration.

Figures, tables and equations

The figures, tables and equations are all very well designed and are presented with good visual quality. The subtitles of figures and tables are well prepared: they contain the information that corresponds to them in a clear way, not being too extensive.

Grammar, spelling and syntax issues

The whole article it's well written in terms of grammar and spelling. But there were identified some aspects that should be improved/corrected, namely in the line(s):

• 42, the first letters of the term "net present value" should be capitalized, as they represent the acronym (NPV) that follows this term;
• 52 and 53, the term “scientific literature” appears repeated, only separated by a comma. So, instead of the repetition, the suggestion "it" could be written;
• 60 and 61, the term “Monte Carlo Simulations” appears repeated, only separated by a period. So, instead of the repetition, the suggestion "this method" could be written;
• 83 the acronym "UN" must be preceded by its full meaning, as it is the first time it appears in the text;
• 101 the terms "ambitions" and "ambitious" appear almost followed, it is suggested that one of them can be replaced by a synonym;
• 106, the punctuation symbol "-" that appears before the word "strategy" must be removed;
• 184 Appendix B is referred to, while Appendix A is referred only later (in line 245). Thus, it is suggested that the letters regarding these appendices can be exchanged, so they can appear in the text in the proper sequence;
• 199 - From this line onwards, the symbology of the equations that emerge does not appear in the text in the vast majority of cases. For example, empty parentheses and blank spaces appear in place of this symbology. The authors must carry out the necessary formatting so that all the symbology can be visible in the intended places;
• 227, 232 and 255, there must be an "and" instead of the comma between the letters "L" and "M";
• 245 there must be a space between the references [32,37] and the word "and";
• 324 there seems to be an extra space between the period after the word “immediately” and the word “This”;
• 347 between the terms “study”, “exploration” and “plan elaboration”, the commas should be replaced by the punctuation mark”;”;
• 401 the expression "Geometric Brownian Motion" does not need to be in the text, but only its acronym, as this expression appeared in full before (on line 65);
• 556, the beginning of section 6 (Patents) is among the text, and should be in a different line.

Semantic and technical issues

The entire article is very well explained. The issues are explained very clearly and the concepts and ideas are very well articulated between themselves. However there are some issues highlighted below are related to the content of the text and technical issues, namely in the line(s):

• 147 to 150 the meaning of the units "Mt/y" is not obvious to any reader. Thus, it is suggested that its meaning (million metric tons per year) could be indicated just before line 147;
• 171 the meaning of the term "NSE3-D3.1" is not obvious to any reader, despite appearing in the reference list (in line 659). Thus, it is suggested that such meaning could be summarily indicated;
• 142 the stakeholders are indicated too generically. It is understandable that there may be anonymity requirements on their part, but it would be important for the authors to assess whether it is possible to specify the functions performed by the various stakeholders indicated, so that the reader can have a more accurate idea of the accuracy associated with the presented data, and by consequence of all the results obtained and the discussion thereof. It is a matter of improving the foundation of the case study of this investigation, through a more detailed specification of the qualifications of its sources of information;
• 557 - Section 6 regarding Patents is extremely short, being unbalanced in terms of length compared to the other sections. Of course this section must be smaller than section 5, but it's too small with just two lines. It is suggested that the title of section 6 could be changed to "Future work", so that this section can be expanded, referring to future questions on the subject. One of them would be, of course, the aforementioned existence of patents on this research work. The authors could also refer to all the questions about the real implementation of this academic research work, which are several, but it is up to the authors to think about them and indicate them in this section 6, to enrich it as much as possible, because now, it is extremely poor.

 

References

The list of references is very well prepared, the number of references is appropriate to the depth of the theme's approach in the article and the text is very well referenced. The references are strong and most of them recent, in the scope of this investigation. But just a few flaws were detected and must be corrected, namely:

• The term “et al.” should not appear on lines 59, 598 and 601;
• Several times throughout the text, the names of the authors referenced appear along with the numerical reference format, and most often, they do not. Therefore, the form of referencing the text must be standardized;
• Throughout the text, numeric references, when there are several, should be separated by commas;
• In the list of references many of the years of the works are not in bold and others are, so there must be a consensus on that.

Comments for author File: Comments.pdf

Author Response

Thank you very much. Please see the attachment for our response. 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

My comments are well addressed, paper can be accepted.

Optional minor note: Following study reviews clean energy and energy management systems at ports. You might bring it to readers' attention in the introduction:

- A review of energy efficiency in ports: Operational strategies, technologies and energy management systems. Renewable and Sustainable Energy Reviews, 112, pp.170-182.

Author Response

Dear reviewer,

Thank you for your suggestion. This reference fits the introduction well. We added this reference (Iris, Siu & Lam, 2021) to our introduction.

Yours sincerely, the authors.