Towards Sustainable Urban Mobility: Voronoi-Based Spatial Analysis of EV Charging Stations in Bangkok

Reviewer:

I would thank the authors for this article and the work achieved behind it. The paper is well structured and organized. City planners and stakeholders can optimize the placement of charging stations to support the transition to electric mobility, reduce emissions, and enhance the sustainability of urban transportation in Bangkok by using a Voronoi-based algorithm tailored to its specific context. What do you think about the following points to be integrated in your work:

·       Network Connectivity: Ensure that charging stations are equipped with robust network connectivity for remote monitoring, management, and payment processing.

·       Smart Charging Infrastructure: Deploy smart charging infrastructure that supports features such as load management, peak shaving, and demand response.

·       Interoperability Standards: Adhere to interoperability standards such as OCPP (Open Charge Point Protocol) to ensure compatibility and interoperability between different charging stations and network operators. This allows EV owners to access charging stations from multiple providers using a single account or payment method.

·       Data Analytics and Monitoring: Implement advanced data analytics and monitoring systems to track charging station performance, energy consumption, and user behavior.

·       Scalability and Flexibility: Design the charging network with scalability and flexibility in mind to accommodate future growth and technological advancements.

Authors’ response

Thank you for your kind words and constructive feedback. We have addressed your insightful suggestions by incorporating discussions on these points into the manuscript, focusing on the needs and interests of our audience. Specifically, we have emphasized the importance of robust network connectivity for remote monitoring, management, and payment processing of EV charging stations to ensure operational efficiency and user convenience. Additionally, we have discussed the deployment of smart charging infrastructure with features like load management, peak shaving, and demand response, which are crucial for balancing energy loads and integrating renewable energy sources. We have also included the need for adhering to interoperability standards such as OCPP to ensure compatibility and interoperability between different charging stations and network operators, thereby enhancing user convenience. Furthermore, we have highlighted the role of advanced data analytics and monitoring systems in optimizing the performance and usage of the charging network. Finally, we have addressed the importance of designing the charging network with scalability and flexibility to accommodate future growth and technological advancements. These additions provide a more comprehensive framework for our readers to understand the critical infrastructure requirements necessary for the successful implementation of an EV charging network in Bangkok.

key changes:

·       New contents were newly added to section 4.4 of the manuscript by addressing critical infrastructure requirements for effective EV charging networks, including robust network connectivity, smart charging infrastructure, adherence to interoperability standards, and the implementation of advanced data analytics and monitoring systems. It focuses on ensuring the efficiency, reliability, and sustainability of EV charging services through technological advancements and standards compliance.

·       The previous contents of section 4.4 were moved to 4.5.

Reviewer:

The study utilizes Voronoi diagrams to identify suitable areas for new electric vehicle charging stations in Bangkok, aiming to enhance spatial equity in service provision. Data sources include population density and service area calculations based on administrative boundaries. Findings reveal varying service loads across different population densities, emphasizing the need for strategic infrastructure planning to meet demand effectively. While the study seems interesting, the authors need to address some concerns to improve the manuscript and make it fit for publication in the journal

Authors’ response

Thank you very much for your detailed and insightful review. Your constructive feedback is greatly appreciated.

Reviewer:

The writing style should be revised to be more academic. Many wordings are not widely used in academic (or technical writing nature). Fix the writing style to make it fit for academic publication. Also, the introduction must include a section that is dedicated to the arrangement of this work.

Authors’ response

The manuscript has been revised to adhere to academic writing standards, ensuring clearer and more formal language. Additionally, a section has been added to the introduction outlining the structure of the paper. Please refer to the last paragraph of the Introduction.

Reviewer:

The writing should also be revised to include a clearer problem statement with specific objective of this work. More discussion on Voronoi diagrams and why it was selected in this study for EVCS selection (among potential peers) are needed.

Authors’ response

The problem statement has been refined, and the specific objectives of the study have been clearly outlined. Additionally, a more detailed discussion on Voronoi diagrams and their suitability for this type of spatial analysis has been provided in the Introduction.

Reviewer:

A major point that I'd like the authors to discuss is the assumption of Homogeneous Demand. The analysis of service areas and population density per charging station assumes a uniform demand distribution across the city. However, variations in EV adoption rates, commuting patterns, and urban demographics could lead to disparities in actual service requirements. The authors need to address this point as it may constitute a major flaw in their analysis.

Authors’ response

The issue concerning the assumption of homogeneous demand has been thoroughly discussed in the "Discussion" section, with a cautionary note initially highlighted in the "Materials and Methods" section. For further details, please refer to the last two paragraphs of the section "4.5 Suitable Areas for Installing Additional Electric Vehicle Charging Stations in Bangkok."

Reviewer:

The study could benefit from a more detailed explanation of the methodology used to calculate population density per charging station service area. In specific, mathematical description would improve the discussion, especially in section 2.1

Authors’ response

The methodology section has been enriched with a detailed mathematical description, particularly in section 2.1. Additionally, we have included a flowchart to facilitate a clearer understanding of the process for readers.

Reviewer:

The accuracy of Voronoi diagrams in representing service boundaries and population density per charging station may be influenced by the resolution of the underlying geographic data. Assessing the impact of spatial data quality on the precision of the analysis could improve the reliability of the results.

Authors’ response

We acknowledge that the resolution of geographic data can significantly impact the accuracy of Voronoi diagrams in our analysis. We have added a discussion in the last paragraph of the 4.5 section to address the potential influence of spatial data quality on our results and the importance of using high-resolution data for more reliable outcomes.

Reviewer:

The paper under review presents a comprehensive analysis to examine the spatial distribution, service coverage, and optimal locations for expanding electric vehicle (EV) charging infrastructure in Bangkok. The paper is interesting and provides valuable results. However, some points need to be addressed.

Authors’ response

Thank you for your thoughtful comments and suggestions. We have addressed your concerns as follows.

Reviewer:

The use of Voronoi diagrams for planning EV infrastructure is sensitive to the distribution and density of input points. Furthermore, Voronoi diagrams assume Euclidean distance metrics, which may not accurately reflect real-world travel times and accessibility, especially in urban environments with complex road networks or transportation constraints. How do the authors propose to overcome these issues?

Authors’ response

The limitations of using Voronoi diagrams have already been acknowledged. However, we suggested integrating additional spatial analysis methods, such as Network Analysis, which considers actual travel distances and urban road networks in the future work. Please refer to section 4.2.

Reviewer:

Many abbreviations, such as EV and NNI, have been defined several times throughout the manuscript. It is sufficient to define them once across the manuscript when they are first used.

Authors’ response

The manuscript has been revised to ensure that abbreviations are defined only once when first used and are consistently used throughout the manuscript.

Reviewer:

The main contributions of this paper are not clear, especially in comparison to studies focused on examining spatial distribution, and optimal locations for expanding EV charging infrastructure in Bangkok.

Authors’ response

The main contributions of the study were stated in the introduction, highlighting its uniqueness and value compared to existing literature. Please refer to the last two paragraphs of the introduction.

Reviewer:

The introduction section should be improved with more recent references.

Authors’ response

Thank you for your feedback. While the statistical data presented in the introduction section remains current, we have taken your suggestion into account and included additional recent references in the discussion section. For further details, please refer to section 4.4, "Infrastructure Requirements for Effective EV Charging Networks."

Reviewer:

Adding a flowchart describing the main steps of the applied analysis strategy is essential.

Authors’ response

A flowchart has been included to visually represent the key steps of the analysis methodology, improving the clarity and comprehensibility of the approach.

Reviewer:

The resolution of the figures is very low. They must be improved.

Authors’ response

The figures have been replaced with higher-resolution versions to enhance their clarity and readability.