Carbon Footprint Analysis for Biomass-Fueled Combined Heat and Power Station: A Case Study
Round 1
Reviewer 1 Report
General Observations and Comments for Author
1. I suggest to rewrite the highlights based on the instructions of the journal to the author
2. Line 13: Avoid using only abbreviations in the abstract, you should write carbon dioxide (CO2) instead of CO2 for very first time.
3. Lines 20-21: You have written CO2e first define it. and clear it for the reviewer. Please try to use full form of abbreviation for the first time in MS.
4. Lines 29-30: write although instead of though whether.
5. Line 46: Give the reference for Figure 1 furthermore color of the figure are poor.
6. Line 55: Write 80 % instead of 80 percent, same sequence should be followed in the complete paper
7. Line 88: Write, Authors (15) conducted instead of authors in
8. Line 91: Write, Researchers (16) quantified instead of researchers in (16) quantified.
9. Line 98: Write one of these terms; assess or identify
10. Line 105: Write LCA of the product instead of life cycle
11. Line 108: Remove it: <To address this issue> it’s not looking suitable
12. Line 112, 113 & 114: I think these lines are not suitable to write here because you are following proper research method, so these lines should be removed
13. Lines 130-131: Put reference
14. Line 133: Write LCA instead of life cycle analysis.. Because you have used full form of this abbreviation before
15. Write references for Figure 2 & 3
16. Line 184: Write power-to-heat instead of pow-er-to-heat
17. Line 194: Write abbreviations of carbon (C), nitrogen (N), sulfur (S) as well
18. Line 213: Use only abbreviation for carbon and carbon dioxide. Try to follow a proper writing sequence
19. Lines 272-273: Follow proper and single writing sequence for all terms. Likewise, ton/hour or ton/h
20. Line 280: It’s not suitable to start a paragraph by using word Whether. You should remove it.
Rewrite the conclusion section according to the finding of the study and give your final recommendation.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The manuscript entitled “Carbon Footprint Analysis for Agricultural Residues Fueled Combined Heat and Power Station: a Case Study” is potentially interesting, however it needs an extensive revision. The remarks are given below.
1. Title needs a change since not all the used materials in manuscript are an agricultural residues
2. The agricultural residues “include rice straw, wheat straw, rice husk, and corn stover, which are mostly left on the fields after harvests and used for fodder and landfill material or burnt in many places. Forestry residues consist of branches, leaves, bark, and other portions of wood.” (Sushil Adhikari, Hyungseok Nam, Jyoti P.Chakraborty Chapter 8 - Conversion of Solid Wastes to Fuels and Chemicals Through Pyrolysis, Waste Biorefinery, Potential and Perspectives 2018, 239-263, https://doi.org/10.1016/B978-0-444-63992-9.00008-2). Therefore wood pellets are neither agricultural nor forestry residues. Pellets are rather biofuel produced from forestry residues.
3. In the Introduction there should be one clear distinction between wastes and residues and the definition of both terms as well as clear distinction between forestry and agricultural residues or wastes.
4. Line 10-11: this sentence suggests that greenhouse gases emissions and pollution are generated only from open burning of biomass residues. GHG and air pollution also become from fossil fuels used in power and heat plants. Therefore this sentence is misleading.
5. Line 16: if the wood chips are not the subject of the study there is no need to mention them in Abstract, because this is confusing.
6. Line 15: The environmental impacts among of various…
7. Line 16: What do you mean by “the richest domestic…”?
8. Line 21-22. The sentence needs to be reworded.
9. Why the environmental benefits of transition from coal to biomass or natural gas is controversial. Please add the examples of studies or analyses which show the benefits or show environmental burden of biomass used in CHP plants instead of coal.
10. Lines 34-41: In the same paragraph wood pellets and chips are once agricultural residues and a few lines later are wood-based fuels. Forestry wastes/residues are not agricultural residues. This must be clearly defined in Introduction.
11. Lines 59-67: I suggest to move this paragraph to Methods. The Introduction can be more overall.
12. Line 68: what do you mean by “(aside from waste)”? What do you mean by waste? Agricultural waste? Or other waste? The terms residues and waste must be clarified. This sentence is contradictory to the table 1.
13. Lines79-82: this sentence suggests that LCA is used only to industrial activities based on the raw materials from agriculture. Please clarify this idea. LCA can be used to any industrial activity or service including the energy production from biomass.
14. Lines 88-97: please avoid the wording/style such as “Authors in [15]” or “Ref [17]”. It would be better: The LCA study for electricity generation by coal alone, biomass alone, and biomass and coal co-firing showed that the….
15. What were the results of studies described in lines 91-97?
16. Since the LCA boundary is from biomass production to slag utilization on the field why in aim the emission hotspots are only considered for biomass supply chain?
17. Figure 3: “2” in CO2 should be in subscript.
18. Is the collecting, transport and production of pellets considered in this study?
19. Line 168: please check this sentence “machine that feats the boiler” Shouldn’t it be: machine that feeds…?
20. Line 170: it should be “chips are fed into..”
21. Line 169-171: This description is not a pellet production. Wood pellets are produced by maturing, drying and compacting of sawdust or wood shavings etc. The wood has to be grind into dust and then compressed into small cylinders called pellets. Heat is applied to the process and the end product is dry and highly compressed. Yours description looks like the beginning of pellets production or production of wood chips.
22. Wheat or any other straw is baled in large round bales on the arable field after grain harvest and then the bales are transported for example to heat and power station. So the transport distance is not from pretreating plant but from arable field and should be assumed on average.
23. Line 175 and 176: do you mean nautical miles? If not, please recalculate the distance to kilometers and the emissions to g per km. Is it a truck or ship because in one sentence there is ship in another a truck.
24. How the biomass is fed to the boiler? Is it the same boiler as it was for coal or it must be changed? Since the coal is crushed and added with air how the bales are fed into a boiler? Are the bales shredded prior to feeding the boiler?
25. Line 184: it should be “power-to-heat”
26. The references are needed for the moisture and LHV assumed for straw and pellets.
27. How the emissions or other environmental impacts were calculated for pretreatment and for transportation.
28. Table 2: in what unit are the values? Please rename the title of the table. Delete (DRY MATTER) and add this information to the unit.
29. Ton is not a metric unit, there should be tonne with abbreviation t.
30. Please use one abbreviation for CO2 equivalents in the whole manuscript. There are at least two different ways used in manuscript and figures.
31. Please use the SI unit e.g kg t-1
32. Did you use the labor in your LCA?
33. In Methods I miss clear information how and what was calculated for acquisition, pretreatment, transportation and slag utilization.
34. Line 223: reword the sentence.
35. Table 3. Why the title is written with capital letters? Please extent the title to make it more describing the table.
36. Table 3: Baling and handing (?) – is it correct?
37. What assumptions were made to calculate the transport of bales and the transport of coal? Truck, train, type of fuel etc.? Be more specific about the assumptions made, please.
38. How the emissions from preparation of pellets were calculated? Be more specific about the assumptions made, please.
39. How the emissions of baling and chopping of straw were calculated? Be more specific about the assumptions made, please.
40. Please unify in whole manuscript: wood pellets or wood pellet.
41. The Results should be more self-explanatory and should include more details.
42. If you consider the straw as an agricultural residue and the soil preparation, sowing and harvest are not included in the LCA because these agricultural treatments are done for grain production, the addition of fertilizers and plant protection products and herbicides also should be excluded from the LCA Inventory. The addition of fertilizers to soil is mainly due to obtaining high grain production.
43. What do you mean by “emissions from machinery” in case of coal? Do you mean the emissions from fuel or emissions from machinery production and usage?
44. Line 237: the sentence needs to be rewritten.
45. Line 247: The combustion of biomass is considered as carbon neutral but the emissions for biomass production originated from at least fuel used for its cultivation is not considered as neutral and can make a huge difference depending on the biomass type and agricultural practices.
46. Line 260: this paragraph is a part of discussion.
47. In discussion please check the words for unnecessary hyphens e.g. eco-nomic, porta-tion
48. The discussion has to be significantly extended. The literature on this issue is large so only 31 references is very little. In Discussion the results should be compared to more references, the explanations in differences between the Authors’ results and those from references should be given. It would be interesting to know how big area of wheat should be cultivated to obtain the amount of straw which is needed for this CHP station. Perhaps the area needed for storage space and how pellets or straw should be store to stay dry in Danish climatic conditions. The discussion should also describe different emission factors and explain why you used these factors and you rejected others. The uncertainty should be shown and discussed.
49. The Conclusions should not be so generic and repetitive respect to previous sentences and concepts. The Conclusions should be written comparing objects of the study and the results obtained.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Please see the attached file.
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.docx
