Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. This paper explains that the investment payback period takes several decades, is this time period too long? Does it still make sense to design the method with such a long duration?

2. Has there been any similar research prior to this? If so, could the authors perform a comparative analysis and include it in the revised manuscript?

Comments on the Quality of English Language

The English writing of this paper can be appropriately revised.

Author Response

Dear Reviewer,

Thank you for reviewing the paper. Please find below answers to your previous comments.

1 - Indeed the payback period for these systems seems to make it not profitable. In order to address this issues, several changes were included in the paper. First, a new scenario was added. In this scenario, by installing OPS only in the terminals with the highest energy needs would result in a significative reduction of the payback period. Even without considering external financing, the payback could be reduced from 36 to 23 years. Secondly, new text was included in the paper to clarify that in most situations, external funding can still be needed to help port authorities to make the necessary changes and cope with regulatory changes forcing them to install OPS,

2 - the introduction section was extended including relevant literature revision and citing different examples of relevant works.

 

Thank you.

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript proposed a a methodology to assess the maximum power needs to provide electric energy for vessels while docked, through OPS. The methodology is implemented in a self-developed Python program that provides different metrics regarding energy needs and also cost comparison between as-is solutions and the application of OPS. The minimum required input is a database regarding the ATA ad ATD of vessels in a specific port or quay under analysis as well as vessel types and their gross tonnage. The topic discussed in the submitted article is very interesting and valuable. However, I have found a few mistakes in the manuscript in English description and pointed out a few places for improvement. There are some obscure equations in the proposed control design process while the stability analysis should be proved in more detail. Besides, some statements in this study should be modified to match the suitable content with the other studies. They need to be checked and updated to make the content perfect.

Minor revision:

(1)        Some equations must be detailed for ease of checking.

(2)        Some references should be updated according to the IEEE format with detailed information.

(3)        The simulation study should be compared with previous results.

(4)        All figures must be revised to become professional.

Major revision:

(5)        The introduction should be more detailed to show the advantages of this method with previous studies ?

(6)        The simulation study should be compared with previous results.

(7)        The methodology should be demonstrated more clearly ?

(8)        What will be solved with the results of this study ? Could research propose some methods to optimize useful power or to reduce maximum power ?

(9)        Experiment studies should be carried out to illustrate the effectiveness of the methodology ?

Comments on the Quality of English Language

Moderate editing of English language required

Author Response

Dear Reviewer,

Thank you for reviewing the paper. Please find below answers to your previous comments.

1 - equations usage were clarified.

2 - A major revision was performed to the references section, including full information (e.g. DOI).

3 - New references were added allowing to compare the results obtained in this work with others found in the literature.

4 - figures were revised to have a more professional look.

5/6 - the literature revision section was extended 8in the introduction), clearly demonstrating the differences between this work and others found in the literature. in this methodology, we perform a time variant (power at every 15 minutes) analysis instead of using average values which focus only on the energy impact. The results showcase the importance of this methodology, because electric grid components need to be designed for the worst case (largest power) and not considering average values.

7 - the paper was restructured to clearly separate the methodology from the use case. The steps of the methodology were further detailed.

 8 - the methodoly provides a straightforward way to assess power needs. it can be used to design OPS or to forecast energy needs in the near future, based on the expected sea traffic. Additional text was included to clarify this aspect.

9 - the proposed use case is based on real data from the port of Lisbon. The installation of OPS systems is completely out of scope of this paper and there are not real load diagrams of ships available in the literature (these could be used to finetune the obtained results). the methodology and implemented tool aim to be used as a decision support instrument for port authorities to decide when and how to invest in OPS.

 

Thank you.

 

Reviewer 3 Report

Comments and Suggestions for Authors

This paper presents a methodology that allows port operators to verify, straightforwardly and transparently, their power needs for Onshore Power Supply applications.

1. The novelty of the work should be explained in detail in the Abstract, Highlights, and Conclusion.

2. The expression of the abstract should be improved. A more detailed presentation of innovation should be conducted as well as the experimental verification.

3. Please try to optimize the expression of your conclusions by summarizing your main special research idea and research achievement briefly.

4. The conclusion can be improved by giving the primary findings with necessary statistical results.

 

Author Response

Dear Reviewer,

thank you for reviewing the paper.

Following your suggestions, the abstract, introduction and conclusion were updated to: a) clearly identify the implemented methodology and provide context within the state of the art, b) to summarize obtained results.

Thank you.

Reviewer 4 Report

Comments and Suggestions for Authors

The authors proposed methodology for assessing power needs for offshore power supply in maritime ports. This topic is of high importance as Maritime ports play a crucial role in the global transportation network, facilitating the movement of goods and fostering international trade. However, they also serve as significant sources of pollutant emissions, which have garnered increasing attention due to the ongoing transition towards cleaner energy sources and environmental sustainability. This study can enable port operators to assess their power needs for Onshore Power Supply applications. It relies on historical data and energy analysis of different types of vessels, ensuring that the required power infrastructure can supply energy to a diverse range of ships and vessels simultaneously. However, authors need to consider following points to revise the manuscript as potential publication. 

 

·      Author’s efforts are appreciated in conducting the study. However, current version of manuscript doesn’t have the broader spectrum in sense of scientific research, Moreover, authors need to elaborate the below mentioned comment.

·      The study is unable to prove the novelty as just the power and docked ships data has been taken from the relevant portals and simple assessments have been made. Likewise, main data regarding vessel’s power need is itself taken from some other work. Furthermore, economic analysis is just on the basis of cost regarding conventional fuels with others. Chapter 2 and 3 presenting main study data acquisition and processing are very generically explained without any data presentation and novel method. 

·      Considered references are just the data reports without any research articles carrying any novel work and are quite old. It will be appreciated if authors consider the more recent study for referencing purposes.

 

 

 

 

 

Author Response

Dear Reviewer,

Thank you for reviewing the paper and for your comments.

the introduction was extended in order to provide context within the state of the art for the developed methodology. multiple works were included in the literature review. It is explained the novelty of this methodology, as we do a power-based analysis while most papers in the literature do an energy-based analysis. Thus, we have time-dependent energy needs that showcase the importance of performing this analysis instead of using average power values. Real traffic data and realistic OPS costs are used (for the port of Lisbon), providing realism to the simulated use case. The methodology aims to be used as a decision support tool and obtained results demonstrate the need to: a) consider a power based approach, instead of considering average values, b) demonstrating existing economic barriers to deploy OPS in a context where regulation is pushing for that.

 

Thank you.

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript has been revised according to the comments of the reviewers. So it can be published in this journal.

Comments on the Quality of English Language

Minor editing of English language required

Author Response

Dear reviewer,

thank you for your comments.

A proof-read was performed, and we performed minor editing of the paper.

Best Regards.

Reviewer 4 Report

Comments and Suggestions for Authors

Author's efforts are appreciated in successfully addressing the comments to reshape the manuscript.

Author Response

Dear reviewer,

thank you for your comments.

A proof-read was performed, and we performed minor editing of the paper.

Best Regards.