In-Company Smart Charging: Development of a Simulation Model to Facilitate a Smart EV Charging System
Round 1
Reviewer 1 Report
This paper presents a simulation model to facilitate a smart EV charging system. The paper is generally well written with sufficient analysis. It can be considered for acceptance if the authors can address the following issues.
- Please ensure that all the variables have been defined or explained clearly.
- The SOC has been used as an indicator of the method, but it can be measured. SOC estimators have been studied in the literature, e.g., DOI: 10.1109/TPEL.2021.3068725; Applied energy 204 (2017): 1264-1274. Such works can be mentioned for completeness.
- The reinforcement learning method has been studied for multi-energy management and battery charging, e.g., DOI: 10.1109/TIE.2021.3070514; DOI: 10.1109/TVT.2020.3025627. Such works can be mentioned to widen the literature review.
- The authors are advised to add more details about the simulation validation.
- The conclusions are not well written. Please give primary findings with statistical results.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper is an interesting practical example of EV charging optimization that many companies may be interested in now that the EV deployment is accelerating.
The Paper is a resubmission of an earlier version of the paper. The paper was improved in several sections, and most of my original comments were answered adequately.
Figure 11: Of the top squares No. 1,2 and 3: The wrong text "government subsidiaries" was corrected to "government subsidies" only in square No. 3. The mistake was NOT corrected in squares No. 1 and 2. Please correct those.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Please remove main captions in all figures. If the caption is an axis caption, please put it to the corresponding axis.
When labelling figures be consistent, use the first letter in uppercase and the rest in lowercase e.g. in Figure 10. Also add labels to axes, where they are missing (Figure 4, 5, etc.)
Modify the first two paragraphs of Section 4 as it now looks like Royal Reesink company advertisement, which is not acceptable in a scientific paper.
Please clarify the legend for Figure 6 as now it is hard to understand, e.g. by placing an explanation above the ellipses in the legend (placed bottom left in figure I suppose).
Please find a more convenient name for the "Out of control" legend label.
Please do a better check of the existing literature, particularly if there are not similar approaches utilizing arrival times coming from surveys as well as different work-related smart charging approaches.
From your paper, it is not clear how the SoC values at arrival are generated and what distributions are used. Please add this information to suitable parts of the paper.
What is the reason for including this sentence: "Two outliers represented long day trips by employees."? Were the two outliers removed or were they kept?
The idea behind the following two sentences "The travel data can be improved by installing gps-trackers in employees’ vehicles.
In our research we did not do that, due to privacy considerations." is discussed in section 4 on line 282, so I recommend removing the two sentence and adding the privacy concern to section 4 to avoid duplicate parts in the paper.
On line 493 is the Appendix number missing.
Increase font in Figures 16 and 17 and all similar figures as it is hard to read them now.
Why is a general conclusion on line 655 in the discussion section and not in the conclusions section?
In the Conclusion section authors say "Current charging infrastructure is still relatively straightforward, charging any connected EV at full speed regardless of the situation, and installing a number of EVSE based on rules of thumb.", however, from Section 3.3 we know that ElaadNL and EVBox are already running a smart charging infrastructure in the Netherlands. Please clarify this in the text.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 4 Report
please explain in-company charger model it is not clear, and discuss possible classifications of types of chargers, and compare with in-company model
it seems you are reviewing number of technologies for EV charging smart features, you need to classify them and provide performance measures and comparison among them
The structure of the paper should reflect current designs of smart features of EV chargers, challenges, then future designs, features, and examples and comparison
in discussions avoid referencing as it should be summarizing your research and findings
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 5 Report
The topic of this paper is interesting to the readers, within the scope of the journal, however prior its publication changes must be done.
The use of English must be improved. The paper includes several grammatical and syntax errors.
The size of several figures must be increased (e.g., Figs 16, 17, etc.)
The Introduction must be revised. The authors must present the general research area to unfamiliar readers and at most to present the current state-of-the-art in order to show the contribution/novelty of their work. Authors must describe/analyse more the current mentioned references and must include many more related references, such as the following:
Lazarou S., Vita V., Christodoulou C.A., Ekonomou L., Calculating operational patterns for electric vehicle charging on a real distribution network based on renewables’ production, Energies, Vol. 11, No. 9, (DOI) 10.3390/en11092400, 2018.
Vita V., Koumides P., Electric vehicles and distribution networks: Analysis on vehicle to grid and renewable energy sources integration, Proceedings of the 11th Electrical Engineering Faculty Conference (BulEF), Varna, Bulgaria, (DOI) 10.1109/BulEF48056.2019.9030787, 2019.
A separate discussion section that will comment on the produced results must be included.
Conclusions must summarize the work presented within the paper.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 4 Report
revisions are fine
Reviewer 5 Report
The authors have conducted the requested changes.
The paper has been significantly improved.
It can be accepted for publication.
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
The paper investigates the problem of in-company EV fleet charging. The paper presents the methodology to choose the key influencing parameters, to design the system architecture and functionality, and to gather information about the realistic use case via a questionnaire. The authors have designed a model to calculate the results of various charging strategies and compared them on selected KPIs.
The problem described is very timely and the approach is original, presents sound engineering approach and presents very interesting insights into the subject. The paper is well structured and English is on a high level. There are only a few minor comments from my side:
l.183: "...to reduce this self-consumption of PV energy." Probably "...to increase self consumption and reduce the export of PV energy." was meant.
Figure 11: Top three squares: Did you mean "Government subsidies" (= financial support) instead of "government subsidiaries"?
Figures 11, 14, 15: Do not introduce the figure before it is referenced in the text.
l.460: "Equal charging (EC)": missing brackets
I find the paper excellent and after the above comments are dealt with recommend publication.
Author Response
Dear Reviewer,
Thank you for the valuable input and feedback. We appreciate the time you spent on formulating potential improvements to our paper. We have taken those into serious consideration, and below you will find our reactions.
Please also find the updated paper with changes highlighted.
Kind regards,
Maarten Bonnema (also on behalf of Steven Haveman and Mike Voss)
Reviewer 1:
Open Review
( ) I would not like to sign my review report
(x) I would like to sign my review report
English language and style
( ) Extensive editing of English language and style required
( ) Moderate English changes required
(x) English language and style are fine/minor spell check required
( ) I don't feel qualified to judge about the English language and style
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Does the introduction provide sufficient background and include all relevant references? |
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Is the research design appropriate? |
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Are the methods adequately described? |
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Are the results clearly presented? |
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Are the conclusions supported by the results? |
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Comments and Suggestions for Authors
The paper investigates the problem of in-company EV fleet charging. The paper presents the methodology to choose the key influencing parameters, to design the system architecture and functionality, and to gather information about the realistic use case via a questionnaire. The authors have designed a model to calculate the results of various charging strategies and compared them on selected KPIs.
The problem described is very timely and the approach is original, presents sound engineering approach and presents very interesting insights into the subject. The paper is well structured and English is on a high level. There are only a few minor comments from my side:
l.183: "...to reduce this self-consumption of PV energy." Probably "...to increase self consumption and reduce the export of PV energy." was meant.
=> you are obviously right. Corrected
Figure 11: Top three squares: Did you mean "Government subsidies" (= financial support) instead of "government subsidiaries"?
=> Again you are right. We have corrected the figure.
Figures 11, 14, 15: Do not introduce the figure before it is referenced in the text.
=> LaTeX has its way in putting figures at certain places. I have tried to work the system to make sure the figures are first mentioned in the text, before appearing.
l.460: "Equal charging (EC)": missing brackets
=> Corrected accordingly!
I find the paper excellent and after the above comments are dealt with recommend publication.
=> Thank you very much. Your comments and feedback have encouraged us to finalize the paper!
Submission Date
14 August 2020
Date of this review
05 Sep 2020 23:00:42
Reviewer 2 Report
This paper presents a simulation model to facilitate a smart EV charging. This paper is generally well written with sufficient descriptions and validations. It can be accepted after addressing the following issues. 1. The abstract should be further polished. The key aspects of research should be given to guide the readers. 2.The conclusion is not well written. It should give the key findings with necessary data. 3. Both the simulation model and charging strategy should be on the basis of accurate knowledge of battery state of charge (SOC). The SOC estimation has been widely studied in the literature, eg, IEEE Transactions on Industrial Electronics (2020), DOI: 10.1109/TIE.2019.2962429; Applied Energy 268 (2020): 114932; Applied energy 204 (2017): 1264-1274. As an enabling technique, some works can be included in the literature review to clarity the big background. 4. The authors are advised to comment more on the merits and disadvantages of the proposed method.Author Response
Dear Reviewer,
Thank you for the valuable input and feedback. We appreciate the time you spent on formulating potential improvements to our paper. We have taken those into serious consideration, and below you will find our reactions.
Please also find the updated paper with changes highlighted.
Kind regards,
Maarten Bonnema (also on behalf of Steven Haveman and Mike Voss)
Open Review
(x) I would not like to sign my review report
( ) I would like to sign my review report
English language and style
( ) Extensive editing of English language and style required
( ) Moderate English changes required
(x) English language and style are fine/minor spell check required
( ) I don't feel qualified to judge about the English language and style
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|
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Yes |
Can be improved |
Must be improved |
Not applicable |
|
Does the introduction provide sufficient background and include all relevant references? |
( ) |
(x) |
( ) |
( ) |
|
Is the research design appropriate? |
(x) |
( ) |
( ) |
( ) |
|
Are the methods adequately described? |
(x) |
( ) |
( ) |
( ) |
|
Are the results clearly presented? |
(x) |
( ) |
( ) |
( ) |
|
Are the conclusions supported by the results? |
(x) |
( ) |
( ) |
( ) |
Comments and Suggestions for Authors
This paper presents a simulation model to facilitate a smart EV charging. This paper is generally well written with sufficient descriptions and validations. It can be accepted after addressing the following issues.
- The abstract should be further polished. The key aspects of research should be given to guide the readers.
=> Done. Unfortunately highlighting does not work with LaTeX in the abstract environment. But it can be easily seen that the text is revised and some more information added.
2.The conclusion is not well written. It should give the key findings with necessary data.
=> Updated the conclusions with a selection of the concrete results obtained during the research.
- Both the simulation model and charging strategy should be on the basis of accurate knowledge of battery state of charge (SOC). The SOC estimation has been widely studied in the literature, eg, IEEE Transactions on Industrial Electronics (2020), DOI: 10.1109/TIE.2019.2962429; Applied Energy 268 (2020): 114932; Applied energy 204 (2017): 1264-1274. As an enabling technique, some works can be included in the literature review to clarity the big background.
=> We did include the SoC of all connected EVs for determining the charging power, indicated by E_bat in the equations. Potentially, the comment arises from the sentence on line 420 in the first submission, stating that “EV model specific charging profiles that take SoC into account” were not (yet) implemented. What is meant by that line is that the point where charging speed is reduced to preserve the battery is EV-type dependent. We did not make such an EV-type based distinction. In the concrete case we presented, this is acceptable, as one specific EV-type is considered for implementation. In a future version of the VeCS model, we may implement this extension.
For the revised version, we have adapted the line to be more clear about this (lines 450-451), and mentioned the noise-tolerant SoC estimation techniques (lines 233-236).
- The authors are advised to comment more on the merits and disadvantages of the proposed method.
=> This comment, and the comments of reviewer 3 have motivated us to expand the state of the art to show current approaches (section 3.3), and reflect on them in light of our findings in the discussion and conclusions (sections 8 and 9). We hope that this way, this comment has been sufficiently addressed.
Submission Date
14 August 2020
Date of this review
07 Sep 2020 03:53:54
Reviewer 3 Report
This paper proposes the development of different charging strategies for electric vehicle fleets and a Vehicle Charging Simulation environment for a company called Royal Reesink. The topic is adequate for the journal. Numerous research projects are being done in this area at the moment. However, there are some points that needs to be improved in order to consider the publication of the paper.
The bibliography and the state of the art is clearly in deficit. It needs to be widely improved. The authors spend page and a half (including the figures) in section 3.1 to describe the NEN-EN-IEC 61851-1:2019 which is a standard so can be consulted by the readers. Section 3.2 describes the concerns related to the increase of EV, some articles are cited but they are quite generic. In section 3.3 "Current solutions" no featured research related to the topic of the article is analysed. Instead, only commercial products, a review (from "Half a decade ago" as the authors states) and the Msd thesis of the first author.
The reviewer recommends the authors to reconsider the state of the art. Using Scopus with the parametric search ("ev" AND "fleet" AND "charging") numerous articles (with high impact) about this topic are found. Some of them also exposing use cases of companies with PV generation (which is the main topic of this article).
The novelty of the research, algorithms or the VeCS is not is not clear. The authors should compare the novelty of this paper with that of existing literature.
Honestly, the reviewer feels that this paper is rather a technical report, not an academic study. No novel charging algorithms or simulation environments are presented.
Finally, the reviewer would like to encourage the authors to improve the existing simulation environment with novel charging strategies and algorithms for in-company EV fleets in order to increase the quality of the paper.
Author Response
Dear Reviewer,
Thank you for the valuable input and feedback. We appreciate the time you spent on formulating potential improvements to our paper. We have taken those into serious consideration, and below you will find our reactions.
Please also find the updated paper with changes highlighted.
Kind regards,
Maarten Bonnema (also on behalf of Steven Haveman and Mike Voss)
Open Review
(x) I would not like to sign my review report
( ) I would like to sign my review report
English language and style
( ) Extensive editing of English language and style required
( ) Moderate English changes required
(x) English language and style are fine/minor spell check required
( ) I don't feel qualified to judge about the English language and style
|
|
|
|
Yes |
Can be improved |
Must be improved |
Not applicable |
|
Does the introduction provide sufficient background and include all relevant references? |
( ) |
( ) |
(x) |
( ) |
|
Is the research design appropriate? |
( ) |
( ) |
(x) |
( ) |
|
Are the methods adequately described? |
( ) |
(x) |
( ) |
( ) |
|
Are the results clearly presented? |
( ) |
(x) |
( ) |
( ) |
|
Are the conclusions supported by the results? |
( ) |
( ) |
(x) |
( ) |
Comments and Suggestions for Authors
This paper proposes the development of different charging strategies for electric vehicle fleets and a Vehicle Charging Simulation environment for a company called Royal Reesink. The topic is adequate for the journal. Numerous research projects are being done in this area at the moment. However, there are some points that needs to be improved in order to consider the publication of the paper.
The bibliography and the state of the art is clearly in deficit. It needs to be widely improved. The authors spend page and a half (including the figures) in section 3.1 to describe the NEN-EN-IEC 61851-1:2019 which is a standard so can be consulted by the readers.
=> Yes, the space we spend on the NEN-EN-IEC 61851 is somewhat large. As you say, the readers of the paper can look up the standard themselves. We do believe that an introduction to the standard is useful for the overall flow in the paper. In the new version we have left the text as is as it is only half a page and stated some relevant aspects of the standard and supports the choice for mode 3 over mode 4, but we reduced the size of the figures to bring their scale more in line with the other figures. Result is that presentation and discussion of the standard now takes approximately one page.
Section 3.2 describes the concerns related to the increase of EV, some articles are cited but they are quite generic.
=> Section 3.2 and the literature cited there are indeed quite generic. That is because we wanted to use those for defining the goals of our research, and in particular the objectives for the system to be implemented by the case company and also be transferrable to other organizations.
In section 3.3 "Current solutions" no featured research related to the topic of the article is analysed. Instead, only commercial products, a review (from "Half a decade ago" as the authors states) and the Msd thesis of the first author. The reviewer recommends the authors to reconsider the state of the art. Using Scopus with the parametric search ("ev" AND "fleet" AND "charging") numerous articles (with high impact) about this topic are found. Some of them also exposing use cases of companies with PV generation (which is the main topic of this article).
=> Thank you for this comment and the suggestion for searching additional references. We have conducted the search and expanded the literature section accordingly. Section 3.3 is now about twice as long to account for solutions from recent literature. We highlight commonalities and differences with our approach. Also, in the discussion (section 8), we refer back to the literature found.
The novelty of the research, algorithms or the VeCS is not is not clear. The authors should compare the novelty of this paper with that of existing literature.
=> While the algorithms used are not novel, the novelty of the research lies in the combination and integration into an easily accessible model – the VeCS model – that can be used by companies that want to investigate the advantages and disadvantages of a possible shift to an EV fleet. The VeCS model is fed in such cases with real-life data from the company (travel behaviour, fleet size, PV generation etc.), and the output regarding number of full and incomplete charges, cost saved and PV export for different strategies for charging speed and connection management are then easily produced. This integrated approach is to our opinion novel, at least we have not seen it in the expanded literature search now in section 3.3. Reference Ivanova 2017 (#37) comes close, but we add some charging and connection management strategies.
With the expanded literature search in section 3.3, and the reformulation of some of the conclusions, we feel that we have dealt with this comment, hopefully to your satisfaction.
Honestly, the reviewer feels that this paper is rather a technical report, not an academic study. No novel charging algorithms or simulation environments are presented.
=> As said, the individual strategies and algorithms by themselves are not really new. However, the combination and integration into one accessible model is. In that sense, this paper is a representation of systems design and engineering (width) more than it is a deep-dive paper that explores one (or a few) aspects to its full depth.
Finally, the reviewer would like to encourage the authors to improve the existing simulation environment with novel charging strategies and algorithms for in-company EV fleets in order to increase the quality of the paper.
=> Thank you for this advice. We consider this as future work, as already stated (and elaborated in this new version) in Section 8.
Submission Date
14 August 2020
Date of this review
07 Sep 2020 13:46:08
Round 2
Reviewer 3 Report
Authors have answered some of the questions but the reviewer still feels that the paper seems more a technical report of a software tool than a novel research contribution in the area. The tool is useful for companies but, in my opinion, only the tool by itself is not a contribution to the scientific community.
As authors exposed in the paper, there are existing solutions on the market for EV charging management. Some of these solutions are currently offering the same technical analysis in terms of energy use, savings, CO2 emissions, SoC, etc. so extrapolate them to in-company analysis should not be a problem. In addition to the ones cited in the paper, it is easy to find in the internet some tools that offers the same characteristics as the proposed by the authors (for example https://www.electriphi.ai/).
As authors states, some other research has been done analyzing the differences between uncoordinated charging and different coordinated charging strategies. It is true that authors have included some additional algorithms but this is not the main topic of the paper (the main topic is the VeCS desing). Maybe authors should improve this part of the paper including more algorithms, including more simulated use cases (number of EV, charging stations, PV energy installed, etc.) and analyzing deeply the differences between to give the paper a more scientific aproach.
In summary, I think that the paper must improve the contribution to the research community including some other novelties and highlight the current ones.
