Vehicle-Integrated Photovoltaics—A Case Study for Berlin

Round 1

Reviewer 1 Report

The authors carried out a study to assess the solar energy potential of parking areas, taking into account the shading of buildings and trees. The study used digital surface models and weather data to simulate solar irradiance. The research is carried out reliably, and the tools used are appropriate. The study shows that VIPV can increase the range of vehicles from 7 to 14 kilometers per day, which corresponds to an average annual increase of more than 2,500 kilometers. The results suggest the average annual economy of reducing grid charging for the studied project. The research done is certainly useful, however, it lacks broader conclusions. Can similar results be expected for other agglomerations? It would be good to formulate conclusions in a global context.

As the cited studies show, the environmental benefits of charging vehicles with solar energy are less than for traditional grid-connected photovoltaic systems. So what is the benefit of the proposed solution and why use it?

Author Response

Dear Reviewer 1,

Thank you for your constructive feedback on our manuscript titled "Potential of Vehicle-integrated Photovoltaics: A Case Study in the City of Berlin." Your insights have been important in enhancing the clarity and depth of our study.

Addressing your point on broader applicability, we clarified in our revised manuscript's conclusion that our nethodology could be applied to either create other case studies or to create a generic model by applying it to many cities and seeing what global results can be seen. However, as this greatly depends on the building shape, parking space positioning, road layout and amount and type of trees, it is beyond the scope of this study.

Regarding the "why use it?" query, our findings indicate that, in Berlin and similar European cities, VIPV's environmental benefits are comparatively modest. This insight led us to propose a title change to "Vehicle Integrated Photovoltaics –ACase Study for Berlin" to better reflect our study's conclusions of there being little potential.

We hope these revisions address your concerns, and we are grateful for the opportunity to refine our work with your guidance.

Sincerely,
Ludger Heide

Reviewer 2 Report

Dear Authors, this paper investigates the potential of vehicle-integrated photovoltaics. The topic is timely and relevant. However, there are some comments and suggestions to improve the quality of the manuscript. The comments are as follows:

·         The introduction provides a broad context but might benefit from a more concise presentation of the specific research gap this study aims to address. Highlighting the novelty of the approach or findings early on could engage readers more effectively.

·         The state of the art could be improved by critically analyzing the limitations of previous studies more deeply and explicitly stating how this study contributes to overcoming those limitations. Suggested literature:

o   https://doi.org/10.1016/j.trd.2021.102810

o   https://doi.org/10.1016/j.energy.2022.123400

·         While the paper attempts to identify a research gap, making this gap more explicit with a direct statement on how the current study addresses it would be beneficial.

·         Again, addressing potential biases in data selection and analysis techniques upfront can strengthen the validity of the research.

·         It's important that the results are not just presented but also interpreted in the context of the research questions. Highlighting the significance of the findings in answering the research questions or solving the identified gap would make this section more impactful.

·         The discussion section should not only compare but also contrast the study's findings with existing literature. Furthermore, discussing the practical implications of the findings and how they can be applied in real-world scenarios would enhance the relevance of the research.

Author Response

Dear Reviewer 2,

Thank you for your constructive comments and suggestions, which have
greatly helped in refining our manuscript, "Potential of
Vehicle-integrated Photovoltaics: A Case Study in the City of Berlin."
Below, we briefly summarize our responses and the changes made:

Introduction Revision

We’ve streamlined Section 3.5 to more clearly articulate the research gap and our novel approach, aiming for immediate engagement with the readers.

State of the Art

The first study you suggested is being discussed in Section 3.3. Your second suggested focuses on home PV installations on conjunction with vehicles from an economic perspective. While this is an interesting study, our economic considerations are on a much more abstract level and therefore not easily comparable.

Research Gap Clarity

The revisions in Section 3.5 and Table 1 now explicitly state the research gap and how our study addresses it, aiming for greater clarity.

Data Selection and Analysis

We maintain our initial approach to potential biases and analysis techniques, prioritizing direct comparability with key studies, such as Brito (2021). We argue that the value of being able to compare our results outweighs the pursuit of more nuanced realism that might lack context for meaningful analysis. Consequently, we have not made changes in this area.

Results Interpretation and Discussion

Our discussion contrasts our findings with existing literature, particularly highlighting how our results differ from or build upon Brito (2021) and Kanz (2020).

We hope these revisions address your concerns and strengthen the
manuscript. We appreciate the opportunity to clarify and enhance our
work based on your feedback.

Kind Regards,
Ludger Heide

Reviewer 3 Report

The presented manuscript proposes an assessment of the solar energy potential of parking spaces in Berlin, taking into account challenges such as buildings and tree shading, using digital surface models and weather data to simulate solar illumination. The manuscript is well prepared in terms of content and editing. Minor corrections or clarifications may be made.

1. The manuscript barely indicates the authors' scientific contribution to the development of the state of the art.

2. It is not presented how the authors intend to practically apply their calculations - how they plan to mark parking spaces or provide information to users, e.g. through applications.

3. Nothing was mentioned about the increased energy consumption of the VIPV vehicle (size of photovoltaic panels, power electronics, increased vehicle weight)

4. It is not shown how the algorithm determining the solar potential for a given location depending on the presence of trees or tall buildings in the vicinity works.

5. Are all drawings shown in north-south orientation - this is not indicated in the drawings.

Author Response

Dear Reviewer 3,

Thank you for your valuable feedback on our manuscript titled "Potential of Vehicle-integrated Photovoltaics: A Case Study in the City of Berlin". We have made several key revisions in response:

1. Scientific Contribution: Section 3.5 has been updated to more clearly highlight our contributions and advancements in VIPV research.

2. Practical Application: Although detailed application strategies are beyond our current scope, we've added a sentence in the outlook section to suggest a potential practical use of our findings.

3. Increased Energy Consumption: We chose not to explore VIPV vehicles' increased energy consumption, as our analysis shows no environmental benefit even without considering these factors.

4. Solar Potential Algorithm: We use the r.sun algorithm for solar potential calculations, focusing on data preparation and evaluation as shown in Figure 1 for clarity.

5. Drawings Orientation: North arrows have been added to two figures to clearly indicate orientation.

We hope these changes address your concerns and clarify our work's impact and methodology.

Thank you for your thoughtful review.

Sincerely,
Ludger Heide

Reviewer 4 Report

The article is interesting from start to finish. The appropriate thing would be to lower the percentage of coincidence with other articles, after that, consider what would be appropriate for your publication.

Author Response

Dear Reviewer 4,

Thank you for your valuable feedback. In response, we've clarified the research gap and questions in our manuscript to highlight its novelty more distinctly, addressing your main concern. We hope this revision makes our contribution clearer.

Kind Regards,
Ludger Heide