Electrification Opportunities in the Medium- and Heavy-Duty Vehicle Segment in Canada^†

Round 1

Reviewer 1 Report

1. The authors suggest that this study considers the practicality of electrifying MD/HD vehicles, but it is unclear to the reviewer how it was evaluated. While different levels of charging are assigned to different vehicle types in the study, decisions are only vaguely explained or not explained at all, make the decision rather arbitrary. The level of charger needed depends on how much energy is required (or how big the battery is) and how long is the charging event, if assuming no change to fleet operation due to electrification, the battery size needs to satisfy the same driving range between refills as a diesel vehicle, and the time window for charging event would depend on vehicle down time of the operation schedule. However, authors failed to provide any of the information mentioned above about fleet operation, make it hard for the reader to evaluate how practical it is to assume certain charger for certain fleet.
2. On page 4, line 128, diesel city bus fuel consumption is assumed to be 78L/100km, cite reference [36] (https://afdc.energy.gov/data/10310). However, the referenced data has transit bus (“city bus” is not one of the categories in the data, but transit bus is) fuel economy at 3.7 MPG diesel, which is equivalent to 64L/100km, that is much lower than the number used by this study. Reference [36] is also used for fuel consumptions for other diesel vehicles (school bus, refuse truck, long-haul truck) in this study, with no discrepancy between [36] and this study. The authors should either correct the fuel consumption for diesel city bus to reflect the cited data, or a correct citation should be provided to support the 78L/100km fuel consumption for diesel city bus.
3. The study calculated electricity cost (fuel cost for electric vehicle) without considering charging efficiency (loss), it is typical to have 10%-15% energy loss during charging for electric vehicle, which means that paying for 100 kWh of electricity to charge the vehicle would only supply 85-90kWh for driving. Ignoring charging efficiency would have the effect to underestimate electricity consumption for electric vehicles, so fuel costs for electric vehicles in this study are 10%-15% less than it should be.
4. The author should also consider the installation and operation cost of onsite charging/refill infrastructure, including the cost of charger, installation cost, operation & maintenance cost, which should also factor in the number of charges needed, based on the size of fleet.
5. On page 8, Figure 1, lines for city bus and refuse truck should be extended beyond $0.35/kWh to show the impact from a full range of electricity price. There is no reason to believe that only long-haul truck can experience high electricity cost due to higher level of charger used or higher electricity rate in the future, city bus and refuse truck may also choose to use high power charging and/or experience higher electricity price.  

Author Response

1. The authors suggest that this study considers the practicality of electrifying MD/HD vehicles, but it is unclear to the reviewer how it was evaluated. While different levels of charging are assigned to different vehicle types in the study, decisions are only vaguely explained or not explained at all, make the decision rather arbitrary. The level of charger needed depends on how much energy is required (or how big the battery is) and how long is the charging event, if assuming no change to fleet operation due to electrification, the battery size needs to satisfy the same driving range between refills as a diesel vehicle, and the time window for charging event would depend on vehicle down time of the operation schedule. However, authors failed to provide any of the information mentioned above about fleet operation, make it hard for the reader to evaluate how practical it is to assume certain charger for certain fleet.

Thank you for bringing this to our attention. The 14 feasibility studies on which this article is based, did not include detailed evaluation of exact battery sizes and specific charge power values. Instead, a more general approach was taken to evaluate whether typical recharging configurations could work for a vehicle in its application. As recharging costs increase with charge power, the lowest charge power solution that would allow the vehicle to perform its daily duty cycle was selected. We have added lines 116-125 to the document to explain this to the reader.

2. On page 4, line 128, diesel city bus fuel consumption is assumed to be 78L/100km, cite reference [36] (https://afdc.energy.gov/data/10310). However, the referenced data has transit bus (“city bus” is not one of the categories in the data, but transit bus is) fuel economy at 3.7 MPG diesel, which is equivalent to 64L/100km, that is much lower than the number used by this study. Reference [36] is also used for fuel consumptions for other diesel vehicles (school bus, refuse truck, long-haul truck) in this study, with no discrepancy between [36] and this study. The authors should either correct the fuel consumption for diesel city bus to reflect the cited data, or a correct citation should be provided to support the 78L/100km fuel consumption for diesel city bus.

We appreciate the reviewer pointing out this discrepancy to us. City bus refers to transit bus in this paper. We used an older copy of the data from DOE which showed a lower fuel economy of 3.0 MPG diesel (78 L/100km) for the transit bus. We have updated our results with the latest data 3.7 MPG diesel (64 L/100km) in Table 4 and the context and Figures accordingly.

3. The study calculated electricity cost (fuel cost for electric vehicle) without considering charging efficiency (loss), it is typical to have 10%-15% energy loss during charging for electric vehicle, which means that paying for 100 kWh of electricity to charge the vehicle would only supply 85-90kWh for driving. Ignoring charging efficiency would have the effect to underestimate electricity consumption for electric vehicles, so fuel costs for electric vehicles in this study are 10%-15% less than it should be.

Thanks for this valuable comment. We fully agree that charging efficiency should be considered in the fuel cost. However, our references do not mention whether the electric vehicle fuel economy (kWh/km) is based on DC battery kWhs or on AC grid kWhs. For passenger vehicles, the ‘window sticker’ represents AC grid power consumption. We therefore assumed that all performance data from our sources is related to the amount of AC grid power required. We indicated this in line 185-191.

 

4. The author should also consider the installation and operation cost of onsite charging/refill infrastructure, including the cost of charger, installation cost, operation & maintenance cost, which should also factor in the number of charges needed, based on the size of fleet.

We agree that for a detailed calculation of recharging costs all of the mentioned aspects should be taken into account. However, these introductory feasibility studies were not meant to be detailed design studies, but more introductory study giving a first indication of the potential to electrify certain vehicle types and applications. Therefore we have used current rates for Level 2  and L3-50 kW recharging and estimated rates for L3-300 kW. These rates include all the cost factors given above). As this is a simplification and different local conditions may also result in differences in charging rate, we have included a sensitivity study to show the influence of the uncertainty in the charging rates.

5. On page 8, Figure 1, lines for city bus and refuse truck should be extended beyond $0.35/kWh to show the impact from a full range of electricity price. There is no reason to believe that only long-haul truck can experience high electricity cost due to higher level of charger used or higher electricity rate in the future, city bus and refuse truck may also choose to use high power charging and/or experience higher electricity price.

From the economic perspective and taking into account their duty cycles, city bus and refuse truck do not need the highest level of charge power related to the highest charging rate. We added this argument in the context (line 275-278).

Reviewer 2 Report

This paper presents the electrification opportunities in the medium and heavy-duty vehicle segment. This paper presents various concerns before it can be considered for publication.

-The Introduction is very poor. The Introduction should clearly present motivations, literature review, and the main contributions. None of these primary elements are presented. Moreover, the study needs to focus on general; the first two paragraphs deal with Canada's situation.

-The methodology is not clear. The main components of it and the motivations for this work need to be presented. I suggest including a figure with a flowchart of the methodology. Moreover, Section 2 seems rather the case study data, which needs to be separated in another section.

 -Figures are very basic and seem to be done in Excel, which is not proper for a scientific journal.

-The main numerical results should be included in the conclusions.

-References are just a bunch of reports. As I previously mentioned, there should be a clear literature review that discusses various journal articles, not reports.

Author Response

This paper presents the electrification opportunities in the medium and heavy-duty vehicle segment. This paper presents various concerns before it can be considered for publication.

-The Introduction is very poor. The Introduction should clearly present motivations, literature review, and the main contributions. None of these primary elements are presented. Moreover, the study needs to focus on general; the first two paragraphs deal with Canada's situation.

Thank you for your comment. This study is focused on Canada. We modified the title and the abstract to improve the clarity on this. The motivation is presented in the Introduction (e.g. net zero in 2050, transportation sector needs to decarbonize etc). We also added a sentence to strengthen it (line 27).

From our perspective, the literature review is extensive, though less form ‘journals’, but more from other sources (more on this in our reply to a later comment). The main contributions are included at the end of the Introduction section.

-The methodology is not clear. The main components of it and the motivations for this work need to be presented. I suggest including a figure with a flowchart of the methodology. Moreover, Section 2 seems rather the case study data, which needs to be separated in another section.

Thanks for this suggestion. In an effort to make our approach clearer, we added a flow chart of the methodology in the Methodology section as suggested (Figure 1). Section 2 data, if referring to the fuel cost data in Table 3, are not for a case study, but they are associated with the different techno-economic analyses. Therefore we decided to keep them in the same place.

-Figures are very basic and seem to be done in Excel, which is not proper for a scientific journal.

Thanks for bringing this up, but these two figures are meant to show the sensitivity results of the energy cost. It is our impression that figures will generally be reproduced by the publisher, so Excel figures should be fine for the submission and review stage.

-The main numerical results should be included in the conclusions.

We agree with this comment, so we have included the main numerical results and ranges in the conclusion.

-References are just a bunch of reports. As I previously mentioned, there should be a clear literature review that discusses various journal articles, not reports.

As we indicated in the article, because electrification of the MD/HD segment is at the nascent stage, information on the newest developments and performance data for these technologies is unfortunately hardly available from journal papers, but mainly from reports. However, many of these reports are from well recognized sources, such as University of California, Columbia University, University of British Columbia, National Renewable Energy Laboratory, Oak Ridge National Laboratory etc. We are therefore confident that valuable information and important conclusions can be evaluated from these reports.

Reviewer 3 Report

Dear Authors,

Thank you for possibility to read that paper. I have some suggestions and notes.

Please reconsider if that paper can be proceed as Article or as Review. If article, the methodology should be expanded. Now there is everything based on other literature. Please read how is provided research and what kind of methods Authors can use in their research. Please explain the methods used in this study. Primary research, secondary research. Some examples of research methods such quantitative, qualitative, deductive or inductive methods, primary, secondary authors can find in the article New technologies and innovative solutions in the development strategies of energy enterprises. HighTech and Innovation Journal, (2020). 1(2), 39-58 or/and Mixed methods research in strategic management: Impact and applications. Organizational Research Methods, 2012, 15(1), 33-56.

Line 44 – it is not clear, if the number 185.000 means totally at the Canadian market or indicate only for 2020?

Line 54 – please check the company name “Tesla and Nicola”. Is it correct? Tesla is surname and Nicola is his name: Nicola Tesla. But maybe you wanted to write two different companies? One Tesla and another one Nicola. So please to rewrite these names.

Table 1 – if authors have no information about weight and fleet size, what authors know? Why these uncompleted information are there in the table? It looks strange.

Table 2 - what does X mean? Does it mean "yes"? And why are there no signs in 2 places of the hydrogen fuel cell column?

Table 3 – what does Level mean?

Table 4 – please explain the idea of the numbers in the table. What does distance drives mean? Is it distance for 1 vehicle or for all vehicles? In 1 month? In year?  ect… I don’t understand that table.

Figure 2 - If there is an operating cost saving of -150 or -50, that means the operating cost has increased, right?

Line 123 – please don’t use so long loop of references, please divide into 2 groups of 2-3 citations.

I hope that my suggestion will be useful for the authors in order to improve that paper.

Author Response

Thank you for possibility to read that paper. I have some suggestions and notes.

Please reconsider if that paper can be proceed as Article or as Review. If article, the methodology should be expanded. Now there is everything based on other literature. Please read how is provided research and what kind of methods Authors can use in their research. Please explain the methods used in this study. Primary research, secondary research. Some examples of research methods such quantitative, qualitative, deductive or inductive methods, primary, secondary authors can find in the article New technologies and innovative solutions in the development strategies of energy enterprises. HighTech and Innovation Journal, (2020). 1(2), 39-58 or/and Mixed methods research in strategic management: Impact and applications. Organizational Research Methods, 2012, 15(1), 33-56.

Thank you for this suggestion. We read up the recommended papers and summarized the approach of our research methods in the Methodology section (line 77 to 80), with a flow chart of the research approach (Figure 1) presented.

Line 44 – it is not clear, if the number 185.000 means totally at the Canadian market or indicate only for 2020?

This is the cumulative number. We rephrased the sentence to clarify that (line 46).

Line 54 – please check the company name “Tesla and Nicola”. Is it correct? Tesla is surname and Nicola is his name: Nicola Tesla. But maybe you wanted to write two different companies? One Tesla and another one Nicola. So please to rewrite these names.

Yes, we wanted to write two company names. As suggested, we changed to “Tesla Inc. and Nikola Corporation” to make this clear.

Table 1 – if authors have no information about weight and fleet size, what authors know? Why these uncompleted information are there in the table? It looks strange.

Weight classes apply to on-road vehicles only. We added this in the table. We also added some more information in the text to make this clear (line 88). While fleet sizes of on-road vehicles are generally recorded, we have not been able to find similar information for off-road vehicles.

Table 2 - what does X mean? Does it mean "yes"? And why are there no signs in 2 places of the hydrogen fuel cell column?

Thank you for pointing this out. We added an explanation for the “X” mark in the table’s title, and more text to make it clear (line 95).

Table 3 – what does Level mean?

This refers to charging level. We added this in the table to increase clarity on this point.

Table 4 – please explain the idea of the numbers in the table. What does distance drives mean? Is it distance for 1 vehicle or for all vehicles? In 1 month? In year?  ect… I don’t understand that table.

We appreciate you mentioning this ambiguity. The numbers represent annual results on a per vehicle basis. We added “per vehicle” into the title, which also indicated that these are annual results. We made the same changes to Table 5 and Table 6.

Figure 2 - If there is an operating cost saving of -150 or -50, that means the operating cost has increased, right?

That’s correct. The negative numbers mean that the operating cost is increased. We added a sentence indicating the meaning of positive and negative numbers (line 270-272).

Line 123 – please don’t use so long loop of references, please divide into 2 groups of 2-3 citations.

As suggested, we divided the citations on Line 123 into 2 groups (now it’s on line 154).

Round 2

Reviewer 1 Report

Review’s comments/responses to the revision and author’s response is marked in blue and underlined:

 

1. The authors suggest that this study considers the practicality of electrifying MD/HD vehicles, but it is unclear to the reviewer how it was evaluated. While different levels of charging are assigned to different vehicle types in the study, decisions are only vaguely explained or not explained at all, make the decision rather arbitrary. The level of charger needed depends on how much energy is required (or how big the battery is) and how long is the charging event, if assuming no change to fleet operation due to electrification, the battery size needs to satisfy the same driving range between refills as a diesel vehicle, and the time window for charging event would depend on vehicle down time of the operation schedule. However, authors failed to provide any of the information mentioned above about fleet operation, make it hard for the reader to evaluate how practical it is to assume certain charger for certain fleet.

Thank you for bringing this to our attention. The 14 feasibility studies on which this article is based, did not include detailed evaluation of exact battery sizes and specific charge power values. Instead, a more general approach was taken to evaluate whether typical recharging configurations could work for a vehicle in its application. As recharging costs increase with charge power, the lowest charge power solution that would allow the vehicle to perform its daily duty cycle was selected. We have added lines 116-125 to the document to explain this to the reader.

I don’t think the author can claim these are “feasibility” studies when there is little consideration about how/if charging can be done to fit current fleet operation. If authors would like to claim that L3-50kW charger is good enough for electric city busses, they should at least provide their assumptions on available recharging time per day and size of battery, driving distance between refuels, and vehicle efficiency (already provided) to convince readers that the charging power is adequate for such vehicle to be fully charged before next trip. The added lines seem to suggest such information is used to decide charging power, but no specifics are provided. Those assumptions should be clearly explained for each vehicle type and added to Table 4/5/6 (or listed in a separate table).      

1. On page 4, line 128, diesel city bus fuel consumption is assumed to be 78L/100km, cite reference [36] (https://afdc.energy.gov/data/10310). However, the referenced data has transit bus (“city bus” is not one of the categories in the data, but transit bus is) fuel economy at 3.7 MPG diesel, which is equivalent to 64L/100km, that is much lower than the number used by this study. Reference [36] is also used for fuel consumptions for other diesel vehicles (school bus, refuse truck, long-haul truck) in this study, with no discrepancy between [36] and this study. The authors should either correct the fuel consumption for diesel city bus to reflect the cited data, or a correct citation should be provided to support the 78L/100km fuel consumption for diesel city bus.

We appreciate the reviewer pointing out this discrepancy to us. City bus refers to transit bus in this paper. We used an older copy of the data from DOE which showed a lower fuel economy of 3.0 MPG diesel (78 L/100km) for the transit bus. We have updated our results with the latest data 3.7 MPG diesel (64 L/100km) in Table 4 and the context and Figures accordingly.

Thank you for considering my comment, I am satisfied with the update.

1. The study calculated electricity cost (fuel cost for electric vehicle) without considering charging efficiency (loss), it is typical to have 10%-15% energy loss during charging for electric vehicle, which means that paying for 100 kWh of electricity to charge the vehicle would only supply 85-90kWh for driving. Ignoring charging efficiency would have the effect to underestimate electricity consumption for electric vehicles, so fuel costs for electric vehicles in this study are 10%-15% less than it should be.

Thanks for this valuable comment. We fully agree that charging efficiency should be considered in the fuel cost. However, our references do not mention whether the electric vehicle fuel economy (kWh/km) is based on DC battery kWhs or on AC grid kWhs. For passenger vehicles, the ‘window sticker’ represents AC grid power consumption. We therefore assumed that all performance data from our sources is related to the amount of AC grid power required. We indicated this in line 185-191.

Thank you for considering my comment and making it clear in the text, I am satisfied with the update.

 

 

1. The author should also consider the installation and operation cost of onsite charging/refill infrastructure, including the cost of charger, installation cost, operation & maintenance cost, which should also factor in the number of charges needed, based on the size of fleet.

We agree that for a detailed calculation of recharging costs all of the mentioned aspects should be taken into account. However, these introductory feasibility studies were not meant to be detailed design studies, but more introductory study giving a first indication of the potential to electrify certain vehicle types and applications. Therefore we have used current rates for Level 2  and L3-50 kW recharging and estimated rates for L3-300 kW. These rates include all the cost factors given above). As this is a simplification and different local conditions may also result in differences in charging rate, we have included a sensitivity study to show the influence of the uncertainty in the charging rates.

As mentioned in reviewer’s response for Comment #1, it makes little sense to claim it is feasible to electrify those fleet vehicles without considering the size and operation details of the fleet. For example, one electric city bus may be able to be fully charged overnight with a L3-50W charger, but a fleet of 100 electric busses would need either 100 charging stations or sharing fewer chargers using faster charging. The former would require bus company to operate 100 charging stations, which could be challenging and costly, and the later would result in higher electricity cost. Question like this should be addressed in the study when comparing electric with diesel and H2 in terms of feasibility and operational cost. Also, sensitivity analysis in the study failed to consider cases when higher charging rate is required, sensitivity analysis in section 3.5 is limited to electricity price that is lower than what is used in the main study, so the example above would not b covered with the sensitivity analysis in Figure 2.

 

1. On page 8, Figure 1, lines for city bus and refuse truck should be extended beyond $0.35/kWh to show the impact from a full range of electricity price. There is no reason to believe that only long-haul truck can experience high electricity cost due to higher level of charger used or higher electricity rate in the future, city bus and refuse truck may also choose to use high power charging and/or experience higher electricity price.

From the economic perspective and taking into account their duty cycles, city bus and refuse truck do not need the highest level of charge power related to the highest charging rate. We added this argument in the context (line 275-278).

It remains unclear to the reviewer why higher level of charging power or higher electricity price should not be applied to those vehicles. Also, while the authors suggested that $0.35/kWh for L3-50W is a common price in Canada, unless there is evidence showing this rate is indeed an upper-bound now and in the future, there is no reason to assume cost of L3-50W charger (used for city bus and refuse truck in this study) may not be higher in certain area or in the future. Also, the reviewer believes that the purpose of sensitivity analysis is to show such uncertainties in both direction, not just for cheaper electricity price.    

Comments for author File: Comments.docx

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

The authors tried to address my concerns; however, I am not satisfied with the revision and the responses. The changes made to the paper are minimal, and the authors mostly have just answered my concerns, with responses that I disagree with. I believe the authors should have a final try to improve the paper and become aware that the paper is very poor in its present form or rejected.

 My main concerns that remain are listed:

 -The Introduction is still very poor. I didn’t ask to modify the abstract nor the title. The motivations are an extensive argumentation for explaining the reasons this work had to be performed. To include a small line is not enough.

 -The contributions are not listed. I expect, for example, an bullet form of three main contributions that highlight the novelty of this work.

 -Methodology: the authors include a figure (of poor quality), but it is still not clear the work that has been done.

-I indicated that for a scientific journal, it is very basic to used Excel as a tool for scientific research. It gives the impression that the work has been performed by an undergraduate student that cannot use more powerful tools to perform quality research. Even if the publisher reproduces the figures, the result’s impression is not proper.

 -“information on the newest developments and performance data for these technologies is unfortunately hardly available from journal papers”  I disagree with the reviewers and gives a terrible impression of the work done. MD/HD EVs papers are widely available in the literature, but the authors may not perform proper research in the databases.

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 3 Report

Thank you very much for your new version of the paper. Now it is correct, but I have one more suggestion concerning your answer, that you can add reference concerning methodology e.g based on XXX we have developed a research model.

Author Response

Thank you for taking time to review our paper. We added the two references as suggested.

Round 3

Reviewer 1 Report

I appreciate the authors made the effort to address my comments with additional details on fleet operation and charging assumption. I believe the article has improved, but there are still issues to be addressed.

The latest revision revealed a significant question of how feasible/affordable is battery electric truck (BET) for long-haul application. The authors choose to adopt 1 MW charger to make a feasible case for long-haul BET, but 1MW charging has not yet been available on the market. Also, without any real data for an unavailable charging technology, the authors assume electricity cost of $0.50/kWh for 1MW charging, which was previously assumed by the author for 350 kW L3 charging, this makes the reviewer to suspect that the cost saving for long-haul BET may be unrealistic, cost of charging (including 1MW charging infrastructure) might be significant underestimated for long-haul BET. While the reviewer questions the usage of unavailable technology in this study, if the authors choose to keep long-haul BET in this study, the authors should clear explain in their discussion and conclusion that long-haul BET requires more advanced charging that has not yet been available on the market, so the feasibility and cost saving for long-haul BET should be treated with extreme caution.

The result in Figure 2 seems to be different from what is presented in Table 5-6. The authors should check the accuracy of both Figure 2&3 and any text in Section 3.5 and Conclusion that is based on those figures. 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

I am still not convinced with this paper. However, I believe the authors improved it.

Author Response

We appreciate that you took time reviewing the paper and providing valuable comments for us to improve it.