Potential and Environmental Impacts of Liquid Biofuel from Agricultural Residues in Thailand

Round 1

Reviewer 1 Report

This study predicted biofuel production based on 3 scenarios which generated based on residue extraction. It can say that this is an updated version of the reference number [22] which published in Sustainability journal in 2013. The manuscript is well written which all the aspects of the scope are already considered. However, there is a big problem with the referencing, as some of them are not included in the text in number order.

I suggest a major revision.

The numbers of keywords are too many.

Line 35: where are the other references? Suddenly reference 11 and 12? What about 2 to 10?

Reference 3 needs to be updated.

Line 65: is reference 35. Suddenly line 75 reference 40. Where are the others?

Line 287: the reference style should be followed by a number in brackets. 

The related text for Tables 4 to 7 should be written in proper place. Now a bit confusing as the text of tables is too far from the tables.

Section 1.2 and 4.1 should be summarized.

Section 4.1 and Table 3 have similarity with published works which should be revised accordingly.

Conclusion flow is not appropriate. The recommendation for future studies should be at the end. 

Author Response

 Reviewer 1 - Review report (round 1)

Comments and suggestions for authors:

: This study predicted biofuel production based on 3 scenarios which generated based on residue extraction. It can say that this is an updated version of the reference number [22] which published in Sustainability journal in 2013. The manuscript is well written which all the aspects of the scope are already considered. However, there is a big problem with the referencing, as some of them are not included in the text in number order.

The numbers of keywords are too many.

Thank you for your comment. I made some revision from [biofuel; bioethanol; biodiesel; Thailand; planning instruments; potential; scenario construction; GHG emissions; economic profit] to [biofuel; Thailand; planning instruments; potential scenario, GHG emissions]

Line 35: where are the other references? Suddenly reference 11 and 12? What about 2 to 10? Line 65: is reference 35. Suddenly line 75 reference 40. Where are the others?

The references I wrote were in alphabetical order, but now I changed.

Reference 3 needs to be updated.

I updated the reference from [Andres RJ, Boden TA, Bréon FM, Ciais P, Davis S, Erickson D, et al. A synthesis of carbon dioxide emissions from fossil-fuel combustion. Biogeosciences. 2012;9(5):1845-71.] to [Landry, Jean-Sébastien and Matthews, H. Damon (2016) Non-deforestation fire vs. fossil fuel combustion: the source of CO2 emissions affects the global carbon cycle and climate responses. Biogeosciences (BG), 13 . pp. 2137-2149. ISSN 1726-4170].

Line 287: the reference style should be followed by a number in brackets.

Thanks for your sharp pointed out. I applied the right form (number) instead of just the name of reference and year.

The related text for Tables 4 to 7 should be written in proper place. Now a bit confusing as the text of tables is too far from the tables.

I moved it to the right place where the below of the sentence mentioned that of contents.

Section 1.2 and 4.1 should be summarized.

I shortened the contents e.g. I removed the contents and made it simple [Previous studies usually used the same extraction rate (20%) to calculate potential biofuel produced. However, since the extraction rate depends on the status of resource utilization by countries, this article will be a feasible research if the same value are applied.] in the sector 1.2 and [Current research focuses on cellulosic ethanol and flexible fuel vehicle (FFV, vehicles which use a bland of ethanol and gasoline) conversion kits. These are not considered to be a type of ‘device,’ as has been suggested by manufacturers. However, there is a certificate system from the EPA (Environmental Protection Agency) that needs to be obtained before selling their kits. Such kits are used for bioethanol and bio-hydrogenated diesel, as well as converting biomass to liquid and algae-based fuel for biodiesel. The production target for second- and third-generation biofuels set by TIEB (2015) for 2036 [17] is 10 kilotonnes of oil equivalent (ktoe) / [The goals are administered based on the challenges of Energy Efficiency (EE) development and production capacity in practice. This energy plan is focused on the yield that would have economic benefit from commercialized technology development. This scenario] in sector 4.1

Section 4.1 and Table 3 have similarity with published works which should be revised accordingly.

In section 4.1, I collected the data from Ministry of energy in Thailand (2016), Vaibhav Dhyani et al (2015), Wai-Honh Leong et al.(2018), and my previous study (Heo and Choi, 2018), GAIN (2017), Hao et al.(2018), and four more articles. The main data is based on Ministry of Energy, however, the structure/frame is mixed and based on different articles. I added REDP contents from different reference (IRENA, 2018) on the table, however, I also revised the tables to figure (below) so make it look differently.

Conclusion flow is not appropriate. The recommendation for future studies should be at the end.

Thank you for your comment. I revised the recommendation part to the end of the conclusion, and put the words ‘In conclusion’ at the second paragraph to separate it. Also, I added some challenges and perspectives in the middle of the paragraph. ‘Further research is needed to estimate the biofuel potential of energetic efficiency that can be expressed as the ratio of energy obtained from some amount of fuel produced to the energy in Thailand. This research focused on the biofuel potential of environmental impact. Also, pre-treatment process to convert residues to biofuel should be investigated’.

Reviewer 2 Report

Your paper "A Prospective Study of Liquid Biofuel from Agricultural Residues in Thailand" is a good piece of paper but I have some advice prior to its publication

1. Limited originality of work

2. Need reference - if anything from the text is not your then must have to have reference

3. Your referencing need to be consistent   

Justification of your paper, aim and objectives are not well presented.

Author Response

Reviewer 2 - Review report (round 1)

: Your paper "A Prospective Study of Liquid Biofuel from Agricultural Residues in Thailand" is a good piece of paper but I have some advice prior to its publication. Justification of your paper, aim and objectives are not well presented.

Limited originality of work

This study estimated liquid biofuel production from agricultural residues in Thailand with three scenarios by different extraction rates. This is updated compared to the previous studies related this sector (S. Kumar et al., 2013; Emmanuel K. Ackom., 2013_Cameroon, etc.). Those articles are based on the data in 2011 and it is needed to be updated. On the other hand, the data used from my paper is based on the year 2017 and added scenarios to make the subject more specific and easier predicting for the future potential.

Need reference - if anything from the text is not yours then must have to have reference

Thank you for your comment. I put every reference if the texts are not mine.

Your referencing need to be consistent  

The references I wrote were in alphabetical order, but now I changed.

Reviewer 3 Report

Submission to be reviewed: A Prospective Study of Liquid Biofuel from Agricultural Residues in Thailand

Journal: Sustainability

This paper deals with the estimation of potential of second-generation biofuel from agri-residues.

This is an interesting topic, which is relevant for the research paper, as well as it is relevant for Sustainability journal.

However, I would point out a few issues, which need to be aimed in order to improve your paper and ensure its publication in a scientific journal.

The comments to be resolved are below:

Firstly, I would like to recommend improving the title. For example, why there is “prospective”. Generally, avoid of the unnecessary words and rather be more specific.

From the title, I would be expecting different study, than you are presenting.

In addition, I have troubles with your chosen format – I would prefer standard IMRAD (Intro, Methods, Results and Discussion). Afterwards, it would be clearer.

For example, figure 3 is quite unclear to me. Especially connection to the mentioned studies?

Few relevant papers, I would recommend you to go through and get inspired by:

Bioenergy Use in the European Union - https://www.mdpi.com/1996-1073/11/10/2703

Tropical Fruit Waste Biomass - https://www.mdpi.com/1996-1073/10/12/2119

Biomass as a Suitable Feedstock for Bioenergy - https://www.mdpi.com/1996-1073/11/12/3366

Low Carbon Power from Biomass - https://www.mdpi.com/1996-1073/8/3/1701

Bio-ethanol production from agro-industrial wastes - https://www.sciencedirect.com/science/article/pii/S1364032118307858

Furthermore, rather add more scientific papers, than reports and various websites, which you are currently referring to.

What could be useful to add is also some Advantages and disadvantages of methods for pre-treatment lignocelluloses materials or comparison of bioethanol and biodiesel plants in their current state in Thailand.

I would recommend you to also more elaborate challenges and future perspectives biofuel in Thailand.

Author Response

Reviewer 3 - Review report (round 1)

: This paper deals with the estimation of potential of second-generation biofuel from agri-residues. This is an interesting topic, which is relevant for the research paper, as well as it is relevant for Sustainability journal. However, I would point out a few issues, which need to be aimed in order to improve your paper and ensure its publication in a scientific journal.

Firstly, I would like to recommend improving the title. For example, why there is “prospective”. Generally, avoid of the unnecessary words and rather be more specific. From the title, I would be expecting different study, than you are presenting.

Thank you for your feedback. I would be expecting that my study is about estimating future potential of liquid biofuel in Thailand and that seems ‘prospective’ to me. However, as you presented your comment, it sounds my study area has a wide-range. So I had decided to change the title from ‘A prospective study of liquid biofuel from agricultural residues in Thailand’ to ‘Potential and Environmental Impact of liquid biofuel from agricultural residues in Thailand’. This new title could be more specific.

In addition, I have troubles with your chosen format – I would prefer standard IMRAD (Intro, Methods, Results and Discussion). Afterwards, it would be clearer. For example, figure 3 is quite unclear to me. Especially connection to the mentioned studies?

That is a good pointed out. I revised the chapter 5 title from ‘Future potential of second generation biofuel’ to ‘Result and discussions’. However, I had been considered about chapter 3 which is titled by ‘research design’ to change as ‘method’. However, I was worried to change it because it is literally close to ‘design of research’ and method sounds more experiment-based article. About figure 3, I was designed to clarify the content of the biofuel potential before evaluating it so that the readers would be more understandable. However, it seems it makes confusion so I revised the figure without the information of references. It could be clearer.

Few relevant papers, I would recommend you to go through and get inspired by:

Bioenergy Use in the European Union - https://www.mdpi.com/1996-1073/11/10/2703

Tropical Fruit Waste Biomass - https://www.mdpi.com/1996-1073/10/12/2119

Biomass as a Suitable Feedstock for Bioenergy - https://www.mdpi.com/1996-1073/11/12/3366

Low Carbon Power from Biomass - https://www.mdpi.com/1996-1073/8/3/1701

Bio-ethanol production from agro-industrial wastes - https://www.sciencedirect.com/science/article/pii/S1364032118307858

Furthermore, rather add more scientific papers, than reports and various websites, which you are currently referring to. What could be useful to add is also some Advantages and disadvantages of methods for pre-treatment lignocelluloses materials or comparison of bioethanol and biodiesel plants in their current state in Thailand.

Thanks for your recommendation. I thoroughly look through those great articles and I got inspired especially the last one ‘Current status and future trends of bioethanol production from agro-industrial wastes in Mexico_Danny Carrillo-Nieves et al.’ Honestly, I was trying to put the contents about pre-treatment and actual production of biofuel in Thailand (Figures below a, b for bioethanol and c for biodiesel_ Source: ThaiOil, 2018_ https://www.thaioilgroup.com/home/business_products.aspx?id=13), however, the study area of this paper would be broad. Because I want to focus on the future potential but the pre-treatment is another field to take a research deeply. In addition, I am also worried that putting the process into this paper that both bioethanol and biodiesel sector and that could be distracted.

_From Carrillo Nieves et al (2018).

                           (b)

        (c)

I would recommend you to also more elaborate challenges and future perspectives biofuel in Thailand.

I added challenges and future perspectives in conclusion section ‘Further research is needed to estimate the biofuel potential of energetic efficiency that can be expressed as the ratio of energy obtained from some amount of fuel produced to the energy in Thailand. This research focused on the biofuel potential of environmental impact. Also, pre-treatment process to convert residues to biofuel should be investigated.  Despite these challenges, …’

Reviewer 4 Report

The majority of statements claim the matter that is known. The analysis performed for the particular country (Tailand) is important, and seems to be a contribution to new knowledge. 

The scenarios discussed show quite large potential of biofuels production in Thailand, and  indicates the perspectives of development of next generations of biofuels production. The economic profit is, however associated mainly with a decrease of carbon dioxide emissions, which is only one of the factors requiring consideration. I understand that discussion of all the factors simultaneously might be difficult, and may be the matter of further analyses. The factor, which is also omitted, is energetic efficiency (or energetic productivity), that can be expressed as the ratio of energy obtained from some amount of fuel produced to the energy needed to produce this particular amount of the fuel . 

Author Response

Reviewer 4 - Review report (round 1)

: The majority of statements claim the matter that is known. The analysis performed for the particular country (Thailand) is important, and seems to be a contribution to new knowledge.

The scenarios discussed show quite large potential of biofuels production in Thailand, and indicates the perspectives of development of next generations of biofuels production. The economic profit is, however associated mainly with a decrease of carbon dioxide emissions, which is only one of the factors requiring consideration. I understand that discussion of all the factors simultaneously might be difficult, and may be a matter of further analyses.

Thanks for your comment. This paper usually focused on the environmental impact and I focused only in the case of Thailand. Currently, a large consumption of conventional fuel (gasoline and diesel) and it should be priority to substitute with the liquid biofuel (bioethanol and biodiesel) (Table 8). In my opinion, the connection with the trading or other expected economic profits from selling biofuel would be proceeded for the further study.

Ex) Table 8. Economic effect on emission trading by scenarios

The factor, which is also omitted, is energetic efficiency (or energetic productivity), that can be expressed as the ratio of energy obtained from some amount of fuel produced to the energy needed to produce this particular amount of the fuel .

Thank you for sharp pointed out. I changed my title as ‘Potential and Environmental Impact of Liquid Biofuel from Agricultural Residues in Thailand’ to be more specific. I plan to do the further research for this paper to measure energetic efficiency. In addition, I add some contents about challenges and perspectives in conclusion section ‘Further research is needed to estimate the biofuel potential of energetic efficiency that can be expressed as the ratio of energy obtained from some amount of fuel produced to the energy in Thailand. This research focused on the biofuel potential of environmental impact. Also, pre-treatment process to convert residues to biofuel should be investigated. Despite these challenges, this study has filled in some data gaps in the current plans and strategies for biofuel utilization …’

Round 2

Reviewer 1 Report

The revised version is acceptable.

Author Response

Comments and suggestions for authors:

: The revised version is acceptable.

è Thank you so much.

Reviewer 2 Report

This seems a paper with good content and a quality presentation. However a further check of English grammar would be useful.

In results - you could add few things related to energy demand and value

Author Response

: This seems a paper with good content and a quality presentation. However a further check of English grammar would be useful.

-          In results - you could add few things related to energy demand and value

è Thanks for your comment. This manuscript has been through English editing by professional editor.

è Instead of adding some contents about energy demand and value in the result section, I mentioned about the further study and challenges in conclusion section of this paper that [Further research is needed to estimate the biofuel potential of energetic efficiency that can be expressed as the ratio of energy obtained from some amount of fuel produced to the energy in Thailand. This research focused on the biofuel potential of environmental impact. Also, pre-treatment process to convert residues to biofuel should be investigated]. Because I was bit worried the contents of this paper would be apart from its intended subject. I will definitely get through about energy demand and value issues deeply related to the liquid biofuel sector in my future study.

Reviewer 3 Report

I acknowledge work done by authors, however, just a few issues to be tackled:

first paragraph does not seem very relevant. 

Line 76 - I / In

Incorporate first paragraph from conclusion into the rest of conclusion.  

Nevertheless, the revised manuscript has adequately addressed the reviewer's concerns and questions, thus it is recommended for consideration for possible publication.

Author Response

I acknowledge work done by authors, however, just a few issues to be tackled (below); nevertheless, the revised manuscript has adequately addressed the reviewer's concerns and questions, thus it is recommended for consideration for possible publication.

-          First paragraph does not seem very relevant. Line 76 - I / In; incorporate first paragraph from conclusion into the rest of conclusion.

è Thanks for pointing out. I removed ‘I’ in front of ‘In’ and the sentence that [Biofuels are not something that only exist in laboratories; they are alternative fuels used in reality] which seems broad from conclusion section so that make it more focused on its own subject of this paper.