Obtaining bioLPG via the HVO Route in Brazil: A Prospect Study Based on Life Cycle Assessment Approach
Round 1
Reviewer 1 Report
Dear authors,
After a careful and thorough review, below are my considerations.
Based on the data presented and the discussion carried out, the present manuscript meets the necessary requirements for it to be considered for publication. However, corrections are necessary.
ABSTRACT
Here it is necessary to standardize the use of nomenclatures. For example “Life Cycle Assessment”, whose acronym is only described in the Introduction section.
1. INTRODUCTION
In the first paragraph the authors explain what Liquefied Petroleum Gas (LPG) means and how bioLPG can be obtained. In this sense, in line 37, the authors comment that the bioLPG “emerges as a promising drop-in fuel”, but they did not explain what it means for a fuel to be classified as “drop-in” and what advantages this fuel has over to conventional fuels. Although many readers may have this science, it is necessary that the authors pay attention to describe some characteristics of the drop-in fuel, as observed in < https://ainsworthenergy.com/products/drop-in-fuels/>.
Regarding bioLPG, HVO as another renewable alternative to fossil diesel in the Brazilian market, how could this fuel option achieve scale-up to meet market demand?
2. MATERIALS AND METHODS
Line 146: in the sentence “the O2 atoms”, in this case “O2” is a molecule. Please check.
Line 169: inform the nomenclature of mono- and bimetallic catalysts and not just their chemical formula.
NiMoS2 = nickel molybdenum disulfide
CoMoS2 = cobalt molybdenum disulfide
NiWS2 = nickel tungsten disulfide
Al2O3 = aluminum oxide (alumina)
Ni = nickel
Pd = palladium
Pt = platinum
Rh = rhodium
Regarding Figure 1, the figure needs to be improved, since the visualization and reading of the identification labels of each part of the diagram is not adequate, even in the printed version the identification of the labels becomes more difficult.
2.2. DESCRIPTION OF FOSSIL LPG MANUFACTURING
What does "LPF" mean?
Regarding temperature information, keep the symbol with a space of the numeric value. See line 195 where it says “70°C” and correct for “70 °C”. Correct for all other occurrences.
2.4. LIFE CYCLE MODELING
Line 255: Is the name “Paulina” spelled correctly?
Figure 2 should also be formatted to improve the readability of identification labels. The subtitles also need to be improved.
3. RESULTS AND DISCUSSION
With the information on the production of bioLPG, together with the Life Cycle Modeling, and Life Cycle Inventory, it was expected that information about a scale-up in the production of this fuel would be presented in the manuscript.
The present study represents an important step towards the spread of different renewable energy sources or sources that partially employ the use of renewable raw materials.
Taking into account the need for more and more renewable fuel options, how does this study approach the question of whether bioLPG can be produced in sufficient quantities so that in the near future this new energy option can be available on the fuel market?
It is very important that in the study the authors present information about costs and scale-up of production, so that the reader can be informed about the real applicability of the production process of this fuel and its scope on a national level.
3.1. IMPACT OF SOYBEAN OIL SUPPLY FROM DIFFERENT REGIONS
In line 475, the authors mention the term "Single-Score Indicator" with the acronym "SSI".
In lines 501, 504, 508, and 521, there seems to have been a misunderstanding with the acronym, as the authors rename the term "Single-Score Indicator" as "ISS".
In line 501, the acronym ISS appears in the sentence "(ISSPR = 6.00 and SSIMS = 6.20)" and is described in Table 6 as "SSI". Correct this information also in Figure 3, on the y-axis. Check these divergences and provide the appropriate corrections.
Figure 3 must be improved. The authors should make it clear what the information on the x-axis is. Also, the font size is too small and the graphs presented should be improved. Provide the graphs with all four sides closed. I recommend that you use, for example, the Origin® software (The Data Analysis and Graphing Workspace) to plot the graphs.
Throughout the manuscript there are different nomenclatures for soybean, i.e. "soybean", "soybean oil", "soy" and "soya". Authors should select an appropriate nomenclature and maintain a writing standard.
4. CONCLUSIONS
The conclusions presented confirm the importance of obtaining bioLPG as an alternative energy source, reducing impacts caused by the use of conventional energy sources. However, a very important issue for the diffusion of the use of bioLPG is in its large-scale production, production that is able to meet the demand for use of this fuel in the domestic market of the country. Thus, I ask if it would be possible for the authors to add a projection for the larger scale production of bioLPG, so that really this energy option can reach consumers.
Author Response
Title of the Article: Obtaining bioLPG via the HVO route in Brazil: a prospect study based on environmental performance assessment
Manuscript Number: sustainability-1974029
Letter to the Reviewer n.1: Comments and Information about changes and adjustments carried out in R1 version
Dear Mr. Reviewer,
First, we would like to express our gratitude for the interventions, comments, criticisms, and suggestions you made during this initial round of evaluation of the study. More than reviewing the manuscript, its analyses were fundamental for improving the research.
We hope that the adjustments (additions and reductions), justifications, and clarifications we have implemented have been sufficient to address these considerations. We remain at your disposal and expect that we have approached the level of excellence that allows this manuscript to be published by Sustainability – MDPI.
Sincerely,
NAM, ILCC, MTS, and LK
Reviewer's Comments n.1
Dear authors, after a careful and thorough review, below are my considerations. Based on the data presented and the discussion carried out, the present manuscript meets the necessary requirements for it to be considered for publication. However, corrections are necessary.
C.: We are pleased to know that, in your opinion, our research meets the minimum (or sufficient) requirements to be published in the Sustainability MDPI. We hope that the adjustments and corrections implemented after this review may have filled in the gaps, resolved the problems and inaccuracies, and contributed to the manuscript surpassing the initial expectation.
RW1: ABSTRACT: Here it is necessary to standardize the use of nomenclatures. For example “Life Cycle Assessment”, whose acronym is only described in the Introduction section.
R.: We understand your position, and, indeed, the recommendation is logical. However, specifically, in this case, we had followed the guidelines of Sustainability-MDPI in the section 'Instructions for Authors', which recommend that:
'(...) Acronyms/Abbreviations/Initialisms should be defined the first time they appear in each of three sections: the abstract, the main text, the first figure or table. When defined for the first time, the acronym/abbreviation/initialism should be added in parenthesis after the written-out form. (...)'.
In any case, we have defined the acronym of Life Cycle Assessment (i.e., LCA) in the Abstract in attention to the recommendation you made with this comment.
RW1: INTRODUCTION:
In the first paragraph the authors explain what Liquefied Petroleum Gas (LPG) means and how bioLPG can be obtained. In this sense, in line 37, the authors comment that the bioLPG “emerges as a promising drop-in fuel”, but they did not explain what it means for a fuel to be classified as “drop-in” and what advantages this fuel has over to conventional fuels. Although many readers may have this science, it is necessary that the authors pay attention to describe some characteristics of the drop-in fuel, as observed in < https://ainsworthenergy.com/products/drop-in-fuels/>.
R.: You are right. Including terms not necessarily known to the reader limits and selects the audience that can be reached (or benefited) by the study. So, the expression 'drop-in' was described and conceptualized in the context in which it appears. In addition, we have also added a bibliographic reference, so interested parties can learn more about this and other technical aspects.
RW1: Regarding bioLPG, HVO as another renewable alternative to fossil diesel in the Brazilian market, how could this fuel option achieve scale-up to meet market demand?
R.: The Government of Brazil has made formal and frequent manifestations that it intends to expand the supply of biofuels produced in the country, both in terms of installed capacity and alternatives (i.e., varieties of inputs and processing technologies). The purpose behind these actions is to resume the movement started in December 2004, with the creation of the National Program for the Production and Use of Biodiesel (PNPB), to stimulate biofuel production, and to support the participation of family farming in its supply chain. The central objective of the strategy is to increase the supply of biodiesel and, with that, its contribution rate to the fuel mixture that moves the national front of trucks (currently at 10%). HVO biodiesel is seen as a consistent option to meet these purposes due to its degree of technological maturity and the domestic availability of inputs for fuel production.
To support its intentions, the federal government not only regulated technical specifications for producing HVO biodiesel in Brazil but also outlined plans (medium and long term) to rebalance the internal biofuels matrix, which currently focuses mainly on the FAME process in terms of technology. As an immediate result, the offer of BioGLP will also be amplified, corroborating the government's expectations (of increasing the diversity of options) in the gas-chemical segment. However, there is no evidence that HVO biodiesel is produced on a sufficient scale to replace fossil diesel or even FAME biodiesel. Therefore, the same applies to BioGLP concerning LPG from non-renewable sources. The Brazilian government's idea is to correct distortions of the current model and increase the competitiveness of the biofuel production market, eliminating regional monopolies and making it more environmentally sustainable by reducing impacts.
Well, we've collected official information that supports this context (and strategy), and prepared a rationale that outlines it, which now was located at the end of the Introduction section. The references on which this reflection was based are presented below:
ANP - Brazilian National Agency for Petroleum, Natural Gas and Biofuels, Resolution 842, 2021, (in Portuguese) Available at: https://atosoficiais.com.br/anp/resolucao-n-842-2021-estabelece-a-especificacao-do-diesel-verde-bem-como-as-obrigacoes-quanto-ao-controle-da-qualidade-a-serem-atendidas-pelos-agentes-economicos-que-o-comercializem-em-territorio-nacional. Accessed: October 26, 2022.
MME - Ministry of Mines and Energy, EPE - Energy Research Office, Ten-Year Energy Expansion Plan, 2021 (in Portuguese). Available at: https://www.epe.gov.br/sites-en/publicacoes-dados-abertos/publicacoes/Paginas/PDE-2031---English-Version.aspx Accessed: October 25, 2022.
MME - Ministry of Mines and Energy, EPE - Energy Research Office, RenovaBio: Biocombustíveis 2030 - Nota Técnica 3: Novos Biocombustíveis, 2017 (in Portuguese). Available at: https://www.epe.gov.br/sites-pt/publicacoes-dados-abertos/publicacoes/PublicacoesArquivos/publicacao-155/EPE%20-%20NT3%20-%20NOVOS%20BIOCOMBUST%C3%8DVEIS%20-%20ARQUIVO%203.pdf Accessed: October 26, 2022.
From this approach, we hope the reader will have a more precise context of the country's expectations regarding biofuels and the role the HVO process may play in producing green diesel and BioLPG.
RW1: MATERIALS AND METHODS
Line 146: in the sentence “the O2 atoms”, in this case “O2” is a molecule. Please check.
R.: Sorry for this mistake. In addition, to avoid misinterpretation, we have adjusted the term 'O2 atoms' by replacing it with 'oxygen atoms'.
RW1: Line 169: inform the nomenclature of mono- and bimetallic catalysts and not just their chemical formula.
NiMoS2 = nickel molybdenum disulfide
CoMoS2 = cobalt molybdenum disulfide
NiWS2 = nickel tungsten disulfide
Al2O3 = aluminum oxide (alumina)
Ni = nickel
Pd = palladium
Pt = platinum
Rh = rhodium
R.: Yes, you're right. To maintain the uniformity of the communication convention we have adopted (and corroborate the guidelines of the Sustainability-MDPI Instructions for Authors), we have added the names and chemical formulas of all these substances and compounds to the List of Nomenclatures that appears at the end of the manuscript. Thank you for making this comment, as it helps the reader better understand the process's description.
RW1: Regarding Figure 1, the figure needs to be improved, since the visualization and reading of the identification labels of each part of the diagram is not adequate, even in the printed version the identification of the labels becomes more difficult.
R.: Another reviewer also commented on the content and quality of Figure 1. Therefore, we chose to review its elements and expand the figure to make it more visual. For that, we decided that it should take up an entire page of the manuscript. We hope that in this way, your considerations in this regard (which are pertinent) have been answered.
RW1: DESCRIPTION OF FOSSIL LPG MANUFACTURING
What does "LPF" mean?
R.: Sorry for this typo. Instead of 'LPF,' we mean 'LPG.' The adjustment has already been provided.
RW1: Regarding temperature information, keep the symbol with a space of the numeric value. See line 195 where it says “70°C” and correct for “70 °C”. Correct for all other occurrences.
R.: We have revised the entire manuscript and made the correction you indicated regarding the temperature units. This form of expression is, in fact, the correct and most suitable for scientific communications.
RW1: LIFE CYCLE MODELING
Line 255: Is the name “Paulina” spelled correctly?
R.: No, the municipality is called Paulínia, as with the refinery. We also made this correction.
RW1: Figure 2 should also be formatted to improve the readability of identification labels. The subtitles also need to be improved.
R.: The same conduct adopted in the revision of Figure 1 was also waived for Figure 2. Therefore, this graphic device also started to occupy an entire page of the manuscript, becoming more visual and improving the reader's understanding of the Product System adopted for applying the LCA.
RW1: RESULTS AND DISCUSSION
With the information on the production of bioLPG, together with the Life Cycle Modeling, and Life Cycle Inventory, it was expected that information about a scale-up in the production of this fuel would be presented in the manuscript. The present study represents an important step towards the spread of different renewable energy sources or sources that partially employ the use of renewable raw materials. Taking into account the need for more and more renewable fuel options, how does this study approach the question of whether bioLPG can be produced in sufficient quantities so that in the near future this new energy option can be available on the fuel market? It is very important that in the study the authors present information about costs and scale-up of production, so that the reader can be informed about the real applicability of the production process of this fuel and its scope on a national level.
R.: We share your opinion on the importance of having more fuel options from renewable sources available in the Brazilian matrix. And as far as we can see, this is also a concern of the federal government - as we hope it has been (better) explained from the adjustments we made in response to your question n. 3. Likewise, we corroborate your reasoning that it would be essential to present information on costs and production scale related to BioGLP so that the reader could have elements about the actual applicability of its processing chain and its scope.
However, the data we collect from official sources (please see the answer to Question #3) is quite restricted. Although they make forecasts of supply (including at a regional level) and demand for biodiesel for 2031 and opine on the infrastructure available for its processing, there is no mention of production scales. In addition, although RenovaBio mentions the economic challenges associated with the expansion of biofuels in Brazil, financial aspects such as production costs, profit margins, or tax incentives to be provided by the government to consolidate them (both current and future options, such as the HVO biodiesel) are not available.
Given these limitations, any exercise of economic order would be fatally influenced by uncertainties. Because of this, we regret not being able to respond to this comment. Anyway, it is important to say that other stages are foreseen in the development of this project. In one of them, we intend to carry out an Eco-efficiency Analysis of BioGLP production arrangements; for that, economic performance data are essential. Therefore, you have our commitment that we will move forward on the financial aspects of the product, not only to formulate a diagnosis regarding this dimension but also to relate it to the environmental performance that its processing achieves for the conditions and variants analyzed. To formalize this intention, we included it in the Conclusions section of the manuscript as an action to be carried out in the future within the scope of this same initiative.
RW1: IMPACT OF SOYBEAN OIL SUPPLY FROM DIFFERENT REGIONS
In line 475, the authors mention the term "Single-Score Indicator" with the acronym "SSI". In lines 501, 504, 508, and 521, there seems to have been a misunderstanding with the acronym, as the authors rename the term "Single-Score Indicator" as "ISS". In line 501, the acronym ISS appears in the sentence "(ISSPR = 6.00 and SSIMS = 6.20)" and is described in Table 6 as "SSI". Correct this information also in Figure 3, on the y-axis. Check these divergences and provide the appropriate corrections.
R.: The correct acronym to describe Single-Score Index is SSI. We have revised all the points you highlighted in your commentary, including Figures 3a and 3b, and have replaced the previously used wilderness with this version.
RW1: Figure 3 must be improved. The authors should make it clear what the information on the x-axis is. Also, the font size is too small and the graphs presented should be improved. Provide the graphs with all four sides closed. I recommend that you use, for example, the Origin® software (The Data Analysis and Graphing Workspace) to plot the graphs.
R.: Here, we also followed your suggestion (which, by the way, later proved to be very good!) and redid Figures 3a and 3b with the help of Origin® software (The Data Analysis and Graphing Workspace). As a result of this action, the quality of those graphics devices has, in fact, significantly improved.
RW1: Throughout the manuscript there are different nomenclatures for soybean, i.e. "soybean", "soybean oil", "soy" and "soya". Authors should select an appropriate nomenclature and maintain a writing standard.
R.: We have carefully reviewed all references to soybean made in the manuscript. As a result, we have opted to standardize the communication convention (or terminology), referring to this oilseed as 'soybean' and the oil extracted from it as 'soybean oil'.
RW1: CONCLUSIONS
The conclusions presented confirm the importance of obtaining bioLPG as an alternative energy source, reducing impacts caused by the use of conventional energy sources. However, a very important issue for the diffusion of the use of bioLPG is in its large-scale production, production that is able to meet the demand for use of this fuel in the domestic market of the country. Thus, I ask if it would be possible for the authors to add a projection for the larger scale production of bioLPG, so that really this energy option can reach consumers.
R.: As we have already reported in the comments prepared in response to your questions n. 3 and no. 11, a careful survey, carried out in official sources and documents published by the Brazilian government could not obtain information that would allow the formulation of a projection for the larger-scale production of bioLPG. The same occurred with cost values and other financial indicators. So, unfortunately, we were also unable to respond to this comment.
Anyway, we decided to give a new wording to the Conclusions section of the manuscript, in which this limitation appears as an aspect to be investigated in future actions foreseen in the project. Likewise, we reiterate here the comment prepared to answer your question n. 11: An Eco-efficiency Analysis will be carried out to assess synergistic and harmful effects associated with the processing of BioGLP in economic and environmental terms.
Author Response File: 
Author Response.docx
Reviewer 2 Report
HVO process is commercially promising for the production of renewable LPG, jet fuel, and diesel. First and second generation vegetable oils and fats are used in the process. The authors focus on soybean oil, a first generation vegetable oil feedstock, as this feedstock is readily available in Brazil. Thus, the paper successfully provides insight specifically on soybean fed HVO process in Brazil.
The authors have used ‘due to’ expressions excessively in the manuscript. Some of these expressions can be exchanged with similar expression with the aim of improving the language flow throughout the text.
The authors have used abbreviations for environmental performance p, such as TA, TET) which are fine with the figures and tables. However in the text, the readers those are not in the field would need to return back and check the meaning for the abbreviations. Thus explaining the important outcomes in paragraphs with the longer version of the name would ease reading.
There are several renewable diesel producers in addition to Neste/Finland, which the authors can add examples in line 138.
In line 146, the expression ‘O2 atoms’ can be changed to ‘O atoms’, and also the ‘different reaction mechanisms’ in line 147 can be exemplified with a couple of references.
In Figure 1, C8-C15 product at the end of the process represent not only green diesel, but also jet fuel. The jet fuel oil expression in C5-C8 carbon range should be revisited, as it might not be in this carbon range.
In Table 2 caption, the expression ‘synthesis’ can be changed to ‘production’, or similar.
Author Response
Title of the Article: Obtaining bioLPG via the HVO route in Brazil: a prospect study based on environmental performance assessment
Manuscript Number: sustainability-1974029
Letter to the Reviewer n.2: Comments and Information about changes and adjustments carried out in R1 version
Dear Mr. Reviewer,
First, we would like to express our gratitude for the interventions, comments, criticisms, and suggestions you made during this initial round of evaluation of the study. More than reviewing the manuscript, its analyses were fundamental for improving the research.
We hope that the adjustments (additions and reductions), justifications, and clarifications we have implemented have been sufficient to address these considerations. We remain at your disposal and expect that we have approached the level of excellence that allows this manuscript to be published by Sustainability – MDPI.
Sincerely,
NAM, ILCC, MTS, and LK
Reviewer's Comments n.2
Reviewer #2:
HVO process is commercially promising for the production of renewable LPG, jet fuel, and diesel. First and second generation vegetable oils and fats are used in the process. The authors focus on soybean oil, a first generation vegetable oil feedstock, as this feedstock is readily available in Brazil. Thus, the paper successfully provides insight specifically on soybean fed HVO process in Brazil.
C.: Thank you very much for understanding our proposal for this study. Your comments and suggestions helped us make both its content and communication more understandable and, with this, contribute to the theme dissemination in Brazil. We hope our adjustments and adequation were enough (in quantity and depth) to respond to your comments.
RW2: The authors have used ‘due to’ expressions excessively in the manuscript. Some of these expressions can be exchanged with similar expression with the aim of improving the language flow throughout the text.
R.: After reviewing the manuscript wording, we conclude that you are right. The expression 'due to' was excessively applied. So, we tried to replace it with synonyms, and when that was not possible, we rewrote the excerpt to improve its presentation and fluidity.
RW2: The authors have used abbreviations for environmental performance p, such as TA, TET) which are fine with the figures and tables. However in the text, the readers those are not in the field would need to return back and check the meaning for the abbreviations. Thus explaining the important outcomes in paragraphs with the longer version of the name would ease reading.
R.: Yes, here you are also correct. We must be more precise if we want the article to be read by researchers and professionals outside the Life Cycle Assessment Area. Thus, in the Results and Discussion section, we've replaced the acronyms used to describe all impact categories with their corresponding names or terminologies.
RW2: There are several renewable diesel producers in addition to Neste/Finland, which the authors can add examples in line 138.
R.: Yes, you're right. Thus, we revised this passage and added other renewable diesel producers to the text as an example of how this market behaves. To support these considerations, we have also introduced the following technical reference in the text:
Su, J., van Dyk, S., Saddler, J., Repurposing oil refineries to "stand-alone units" that refine lipids/oleochemicals to produce low-carbon intensive, drop-in biofuels. Journal of Cleaner Production, 376, 134335, 2022. DOI: https://doi.org/10.1016/j.jclepro.2022.134335
RW2: In line 146, the expression ‘O2 atoms’ can be changed to ‘O atoms’, and also the ‘different reaction mechanisms’ in line 147 can be exemplified with a couple of references.
R.: Sorry for this mistake. In addition, to avoid misinterpretation, we have adjusted the term 'O2 atoms' by replacing it with 'oxygen atoms'.
Furthermore, to support the passage that mentions the existence of different mechanisms for removing oxygen atoms from the fatty acid structure, we followed your suggestion and added the following references:
Hilbers, T.J., Sprakel, L.M.J., van den Enk, L.B.J., Zaalberg, B., van den Berg, H. and van der Ham, L.G.J Green Diesel from Hydrotreated Vegetable Oil Process Design Study. Chem. Eng. Technol., 38, 651-657, 2015. DOI: https://doi.org/10.1002/ceat.201400648
Amin, A. Review of diesel production from renewable resources: Catalysis, process kinetics and technologies, Ain Shams Engineering Journal, 10, 821-839, 2019. DOI: https://doi.org/10.1016/j.asej.2019.08.001
Tirado, A., Ancheyta J. Defining appropriate reaction scheme for hydrotreating of vegetable oil through proper calculation of kinetic parameters. Fuel, 242, 167-173, 2019. DOI: https://doi.org/10.1016/j.fuel.2018.12.100
RW2: In Figure 1, C8-C15 product at the end of the process represent not only green diesel, but also jet fuel. The jet fuel oil expression in C5-C8 carbon range should be revisited, as it might not be in this carbon range.
R.: Once again, sorry for this technical failure. We revised Figure 1, reordering and correcting the name (and their output positions) and carbon ranges of fuel products (i.e., green naphtha, jet fuel oil, and green diesel) that leave the hydrocracker.
RW2: In Table 2 caption, the expression ‘synthesis’ can be changed to ‘production’, or similar.
R.: Thanks. In this case, we opted to use ‘production’ instead of ‘synthesis’ in the caption of Table 2.
Author Response File: Author Response.docx
Reviewer 3 Report
The study entitled, “Obtaining bioLPG via the HVO route in Brazil: a prospect study based on environmental performance assessment” has focused on the environmental impacts of obtaining bioLPG from HVO technology by using the Life Cycle Assessment (LCA) technique. This is a good endeavor in the generation of biofuels as a renewable and ecofriendly energy source. I recommend the following changes for improvement of the manuscript:
i. The title of the study, “Obtaining bioLPG via the HVO route in Brazil: a prospect study based on environmental performance assessment” may be revised as, “Obtaining bioLPG via the HVO route in Brazil by using the Life Cycle Assessment technique”. This will encompass all the aspects including ‘cradle-to-gate’ scope as well as environmental impacts and environmental performance assessment. If the authors deem fit then only the word, “prospect” may be replaced with “prospective” in the title and may retain the existing title.
ii. Page 1, Line 18, replace the word “environment-mental performance” with “environmental performance”.
iii. Introduction section, page 2 and onwards, authors have carried out a thorough review of the existing literature on LCA. More focus should be given to the rationale of the study instead of an in-depth literature review.
iv. Materials and Methods section, Page 4, Line 183, the word, “LPF” should be replaced with, “LPG”.
v. Page 5, Line 213, the acronym, “OS” should be corrected as, “SO” otherwise the detailed correct name should be written in the first mention and then may be abbreviated later in the manuscript.
vi. Page 7, Line 251 and onwards, “we based the life cycle modeling on secondary data”. “The temporal coverage for data collection was defined as the entire year of 2018”. Since the work is not based on primary data, the details regarding secondary data as well as the specific time period of the entire year of 2018 needs to be highlighted in the abstract as well as in the introduction section.
vii. Global Warming Potential (GWP) was lowest for fossil LPG (0.62 Kg CO2 eq.) compared with the bioLPG in the 20 scenarios as given in Table 4. Similarly, PED for fossil LPG was 58.3 MJ compared with the bioLPG which was mostly above 60 MJ in most of the scenarios. Fossil LPG better performed in most of the scenarios with respect to EROI, PMF, TA, TET and dLUC compared to bioLPG. Authors should elaborate and emphasize on how to improve the performance of bioLPG compared with fossil LPG with respect to GWP, EROI, PMF, TA, TET and dLUC and for making it more sustainable and ecofriendly.
viii. Page 16, in Nomenclature, correct the complete name of the acronym “EROI” as Energy Return on Investment.
Author Response
Title of the Article: Obtaining bioLPG via the HVO route in Brazil: a prospect study based on environmental performance assessment
Manuscript Number: sustainability-1974029
Letter to the Reviewer n.3: Comments and Information about changes and adjustments carried out in R1 version
Dear Mr. Reviewer,
First, we would like to express our gratitude for the interventions, comments, criticisms, and suggestions you made during this initial round of evaluation of the study. More than reviewing the manuscript, its analyses were fundamental for improving the research.
We hope that the adjustments (additions and reductions), justifications, and clarifications we have implemented have been sufficient to address these considerations. We remain at your disposal and expect that we have approached the level of excellence that allows this manuscript to be published by Sustainability – MDPI.
Sincerely,
NAM, ILCC, MTS, and LK
Reviewer's Comments n.3
Reviewer #3:
The study entitled, “Obtaining bioLPG via the HVO route in Brazil: a prospect study based on environmental performance assessment” has focused on the environmental impacts of obtaining bioLPG from HVO technology by using the Life Cycle Assessment (LCA) technique. This is a good endeavor in the generation of biofuels as a renewable and ecofriendly energy source.
C: We want to thank you for this introductory comment. This indicates that you understand our expectations with this project and its importance for biofuel production in Brazil. Also, we want you to know that we will try hard to respond to your suggestions. We understand they were constructive and that your main objective was to raise the level of research. Thank you very much!
RW3: I recommend the following changes for improvement of the manuscript: The title of the study, “Obtaining bioLPG via the HVO route in Brazil: a prospect study based on environmental performance assessment” may be revised as, “Obtaining bioLPG via the HVO route in Brazil by using the Life Cycle Assessment technique”. This will encompass all the aspects including ‘cradle-to-gate’ scope as well as environmental impacts and environmental performance assessment. If the authors deem fit then only the word, “prospect” may be replaced with “prospective” in the title and may retain the existing title.
R.: Your suggestion is quite interesting. We compared it to the title we had previously formulated and pondered a possible replacement. After reflecting a little, we concluded a mixture of the two proposals could better describe what we intended to do in this study. Therefore, the title of the manuscript in this new version has become:
'Obtaining bioLPG by the HVO route in Brazil: a prospective study based on the Life Cycle Assessment approach’.
RW3: Page 1, Line 18, replace the word “environment-mental performance” with “environmental performance”.
R.: Sorry for this typo. It has already been corrected.
RW3: Introduction section, page 2 and onwards, authors have carried out a thorough review of the existing literature on LCA. More focus should be given to the rationale of the study instead of an in-depth literature review.
R.: Looking at the issue from this perspective, we conclude that you are right. The idea of ​​presenting the reader with the most recent status available in the technical literature on the topic addressed by the study does not seem to have had the effect we had hoped for. This may have occurred eventually due to the lack of clarity regarding the context in which the research is inserted.
Briefly and objectively, the Government of Brazil has made formal and frequent manifestations that it intends to expand the supply of biofuels produced in the country, both in terms of installed capacity and alternatives (i.e., varieties of inputs and processing technologies). The objective of these actions is to resume the movement started in December 2004, with the creation of the National Program for the Production and Use of Biodiesel (PNPB), to stimulate the production of biofuels and support the participation of family farming in its production chain. The strategy's central objective is to increase biodiesel's supply and, therefore, its contribution rate to the fuel mix that drives the national truck front (currently at 10%). HVO biodiesel is seen as a consistent option to meet these purposes due to its degree of technological maturity and the national availability of inputs for fuel production.
To support its intentions, the federal government not only regulated technical specifications for producing HVO biodiesel in Brazil but also outlined plans (medium and long term) to rebalance the internal biofuels matrix, which currently focuses mainly on the FAME process in terms of technology. As an immediate result, the offer of BioGLP will also be expanded, corroborating the government's expectations (to increase the diversity of options) in the gas-chemical segment. However, there is no evidence that HVO biodiesel is produced on a sufficient scale to replace fossil diesel or even FAME biodiesel. Therefore, the same applies to BioGLP concerning LPG from non-renewable sources. The Brazilian government's idea is to correct distortions in the current model and increase the competitiveness of the biofuel production market, eliminating regional monopolies and making it more environmentally sustainable by reducing impacts.
Well, we collected official information that supports this context (and strategy) and prepared a rationale that outlines it, which is now at the end of the Introduction section. Thus, the references on which this reflection was based are presented below:
ANP - National Agency of Petroleum, Natural Gas and Biofuels, Resolution 842, 2021, Available at: https://atosoficials.com.br/anp/resolucao-n-842-2021-estabelece-a-especificacao -do-diesel- green-as well as-the-quality-control-obligations-to-be-fulfilled-by-the-economic-agents-who-market-it-in-national-territory. Access: October 26, 2022.
MME - Ministry of Mines and Energy, EPE - Energy Research Office, Ten-Year Energy Expansion Plan, 2021. Available at: https://www.epe.gov.br/sites-en/publicacoes-dados-abertos/publicacoes/ Pages/PDE-2031---English-Version.aspx Accessed: October 25, 2022.
MME - Ministry of Mines and Energy, EPE - Energy Research Office, RenovaBio: Biofuels 2030 - Technical Note 3: New Biofuels, 2017. Available at: https://www.epe.gov.br/sites-pt/publicacoes- open-data/publications/PublicacoesArquivos/publication-155/EPE%20-%20NT3%20-%20NOVOS%20BIOCOMBUST%C3%8DVEIS %20-%20ARQUIVO%203.pdf Accessed: October 26, 2022.
From this approach, we hope that the reader has a more accurate context of the country's expectations regarding biofuels and the role the HVO process can play in producing green diesel and BioLPG. Also, we hope to have filled the gap you point out.
RW3: Materials and Methods section, Page 4, Line 183, the word, “LPF” should be replaced with, “LPG”.
R.: Also in this case, sorry for the typing failure. We already correct it.
RW3: Page 5, Line 213, the acronym, “OS” should be corrected as, “SO” otherwise the detailed correct name should be written in the first mention and then may be abbreviated later in the manuscript.
R.: Please, sorry again. That adjustment was also implemented.
RW3: Page 7, Line 251 and onwards, “we based the life cycle modeling on secondary data”. “The temporal coverage for data collection was defined as the entire year of 2018”. Since the work is not based on primary data, the details regarding secondary data as well as the specific time period of the entire year of 2018 needs to be highlighted in the abstract as well as in the introduction section.
R.: Yes, you're right. From this comment, we realized that important information about the study's design was specified only in section 2.4. Life Cycle Modeling, when, in fact, they should be disseminated in other elements of the manuscript, such as the Abstract and the Introduction section. Therefore, we reviewed these passages and added information on the type of data (secondary) used in the investigation and on aspects related to their quality, specifically concerning the temporal, geographic, and technological coverages adopted for modeling the product system. Finally, one more correction: the data and information used to describe the product system date from the 2020-2021 biennium, not the full year 2018. This inaccuracy was also corrected during the review of the manuscript.
RW3: Global Warming Potential (GWP) was lowest for fossil LPG (0.62 Kg CO2 eq.) compared with the bioLPG in the 20 scenarios as given in Table 4. Similarly, PED for fossil LPG was 58.3 MJ compared with the bioLPG which was mostly above 60 MJ in most of the scenarios. Fossil LPG better performed in most of the scenarios with respect to EROI, PMF, TA, TET and dLUC compared to bioLPG. Authors should elaborate and emphasize on how to improve the performance of bioLPG compared with fossil LPG with respect to GWP, EROI, PMF, TA, TET and dLUC and for making it more sustainable and ecofriendly.
R.: Our intention with this research was to conduct a prospective trial of how bioGLP HVO processing in Brazil would behave in terms of environmental performance. According to its original conception, the study intended to analyze the possibilities and alternatives of raw materials and macro-level variables associated with HVO technology. In this context, comparing the results obtained with those achieved by fossil LPG would serve mainly as a guideline. We expected to use this data in the next stage of the project when we intend to carry out more specific analyses and test solutions to improve the environmental performance of bioLPG, to be applied to the arrangements that stood out from the others in this initial stage.
On the other hand, this comment made us see the process differently, so we decided to go ahead with the strategy already in this initial manuscript. So, we've included a rationale at the end of the Results and Discussion section in which we describe measures that could improve the lifecycle performance of bioGLP processing in a way that (potentially) makes it more sustainable and eco-friendly, precisely as you mentioned. The extract in question is reproduced below. However (and logically), it must be analyzed within the context in which it is inserted.
‘(…) This exploratory study fulfilled its original objective of verifying the environmental performance of obtaining bioLPG from the HVO route for conditions available in Brazil. However, the initial expectations that fuel from renewable sources would generate minor impacts than its fossil counterpart were not confirmed, even for the arrangements that obtained the best results among the analyzed options. The reasons for this have been exposed and discussed in detail in this section. On the other hand, there are technically robust alternatives (or pathways), which, when implemented at different stages of the bioGLP production chain, could reduce adverse effects on the environment and thus make it more environmentally sustainable and eco-friendly.
An example of conduct within this line of the approach consists of replacing natural gas with bioLPG as a source of heat generation in the oil extraction units (during the pressing of the grains) and in the HVO plant, which could even be designed from of the concept of energy integration (EI). These actions aim to reduce system contributions to Global Warming Potential and Primary Energy Demand.
Another cause of impacts for the same categories lies in the origin of the hydro-gen. Although the electrolysis technology has proved to be more suitable than the steam reforming of hydrocarbons for the generation of this asset, the production of H2 can still be less aggressive. According to the Energy Research Company (EPE), electrolysis can be conducted with an electrical grid consisting only of wind and photo-voltaic sources, thus giving rise to the so-called 'green H2' [41]. The same source also suggested ways to reduce the impacts of Global Warming Potential and Primary Energy Demand, the manufacture of H2 via steam reforming of natural gas, with EI and coupled to a Carbon Capture Usage and Storage (CCUS) system ('blue H2'), and the thermal cracking of methane, also with EI + CCUS ('turquoise H2').
The selection of the most suitable location for implementing the HVO unit is an-other management procedure that tends to yield environmental benefits. In addition to the proximity to fuel consumption centers located in the Southeast region of Brazil, this choice must take into account the sources of production of raw materials, which in the case of soybeans, are concentrated in the Midwest and South of the country. On the other hand, the H2 production technology will also influence this process since the electrolysis should be installed on the coast. At the same time, the logic based on the treatment of natural gas, methane, or hydrocarbons should be close to (or perhaps even inside) refineries. The location of the process units will focus on transport logistics, which in addition to contributing to GWP and PED, emits precursors for Terrestrial Acidification and Fine Particulate Matter Formation. An even longer-term measure would be to explore substituting road for rail for the transportation of soybean grains or oil.
The performance of the process in terms of Terrestrial Ecotoxicity necessarily in-volves the reduction of losses of fertilizers (phosphate and nitrogen) and agrochemicals. For this to occur, it is suggested to implement intercrops between soybean and corn, or even rotational crops, soybean-corn for hot and dry regions (MT, MS, and GO) and soybean-oats, wheat, or barley, for cold areas (PR and RS). In addition to reducing the primary macronutrient needs of crops, these alternatives curb losses and distribute environmental loads (and therefore impacts) among agricultural products [54]. Also, in long-term measures, it would be worth investing in genetic research to generate more pest-resistant strains of soybeans. Finally, effects resulting from direct Land Use Change could be attenuated if soybean crops were installed where pasture areas, as is already occurring in Mato Grosso, or degraded areas [31]. Another possibility, which would also influence the contributions to TE, would be to seek (or develop) management practices capable of increasing agricultural productivity at the regional level (…).’
References:
- ABIOVE – Brazilian Association of Vegetable Oil Industries, Monthly Surveys, 2020. (in Portuguese) Available at: https://abiove.org.br/en/statistics/, Accessed: 11-April-2022.
- Borghi, E., Karam, D., Foloni, J.S.S., Magalhães, P.C., garcia, R.A. Aspectos agronômicos da cultura da soja a serem considerados na implantação do cultivo intercalar antecipado – Antecipe. Empresa Brasileira de Pesquisa Agropecuária – Embrapa. Comunicado Técnico n. 251. 2021. (in Portuguese). Available at: https://ainfo.cnptia.embrapa.br/digital/bitstream/item/226752/1/COT-251-Aspectos-agronomicos-da-cultura-da-soja-no-Antecipe-Emerson-Borghi.pdf. Accessed: October 29, 2022.
RW3: Page 16, in Nomenclature, correct the complete name of the acronym “EROI” as Energy Return on Investment.
R.: Yes, you are right. We review the meaning of the acronyms EROI in the Nomenclature list
Author Response File: Author Response.docx
