Quantifying the Flexibility of Electric Vehicles in Germany and California—A Case Study
Round 1
Reviewer 1 Report
This study presents an analysis of EVs' flexibility for charging at home based on collected data from the field (Germany and the US). The analysis includes the optimal charging schedule cost with different tariffs and charging powers. While the content of the data analyzed can be a good resource for the researchers in the field, it is not presented in detail.Also, the analysis of the optimal charging schedule needs to be explained in detail as well.
- Deep analysis with more details about the collected data is required.
- What is the aim of including a penalty factor K into the objective function and how does it serve?
- it would be more meaningful to show the availability of battery capacities (energy in batteries) rather than vehicle availability in Figures 3 or 4-5. What are the types of car/battery sizes? Any info about this is not given.
- Most of the figures are not clear, have legibility problems.
- What is the duration in Figure 5/ Table-3? Week/year/total observed time? it should be mentioned the data should be converted into a daily/weekly or yearly basis whatever they are the best.
- the RTP data used should be given as tabular form.
- What does it mean by asap in the first control strategy (Line 341)? how was it incorporated in the objective function/ implemented? The same can be said for the statement in Line 345. Make no sense that is incomprehensible.
- The control strategies with minimal price increments need to be explained in more detail. What does it refer and how was it implemented in the objective function?
- In terms of charging power option, why is the 22kW option studied as this study considers only residential charging? 22kW requires 3phase which is not available at most of the residential premises.
Author Response
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Reviewer 2 Report
High scientific level article on a subject currently of crucial importance.
Scientific development is relevant and sufficiently clear. It is well presented and the conclusions reflect the content developed in the document.
It would be interesting to extend this study to other countries in the European space, as it will have important consequences for the new regulation of the electricity sector.
In my opinion that it should be published in the current version.
Author Response
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Reviewer 3 Report
This case study is very interesting and will surely interest everyone who is interested in electromobility.
There are a few minor errors that need to be fixed:
Fig. 4 - I would recommend removing the decimal point on the y-axis for picture number 5 (picture number 4 is fine)
It would be better to insert figure 3 differently than between the desciption of figure 4 and 5.
In the row 430 is written table 5 and table 5. The authors probably mean table 5 a table 6.
Row 469: Incorrectly positioned parenthesis "previous section)".
I would recommend removing the decimal point on the y-axis for figure 6 (a) and c)), adds a description to the b) and d) y-axis and moving the legend to the right, off the graph (one legend would be enough given that this is taken as a single figure - not four)
Fig 8. - To the caption of Figure 8, I would add that these are electric vehicles (Positive flexible power per available ELECTRIC vehicle (kW * EV -1 )
Fig 9 - I would recommend moving the legend to the right, off the graph
For formal publications, essays, and books, AM and PM should be capitalized.
The presented article is written well. Except for the above details, the article can be overall recommended for acceptance.
Author Response
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Reviewer 4 Report
The paper presents a detailed case study of the flexibility potential of electric vehicles for fixed and dynamic prices, for three charging power levels considering Californian and German user behaviour. The developed model uses publicly available vehicle and mobility data from field trials in the USA and Germany, cost-optimizes the charging process of the vehicles, and then calculates the flexibility of each electric vehicle for every 15 minutes.
The topic is very interesting and the manuscript is well written. The novelty of the paper is very clearly defined. This paper presents a thorough analysis of cost optimal charging schedules and flexibility potential of more than 15,000 vehicle availabilities at home for five operating strategies, and three maximal charging power levels. Whereas the calculation of cost optimal charging schedules belongs to the state of the art, the quantification and analysis of the available flexibility of EV complements and enhances the existing literature.
The paper is comprehensive and the results seem coherent and described with sufficient clarity. The conclusions of the paper reveal results of generic value.
The paper may be recommended for publication, but the following issue need to be addressed before publication: the text and English language in the paper have to checked, edited and corrected by authors preferably by a native English speaker.
Author Response
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