1. This below is a longer-than-usual recommendation for a new lengthy Chinese biochar paper:
“ Review of Carbon Fixation Evaluation and Emission Reduction Effectiveness for Biochar in China “ Dongdong Feng, Shizhang Wang, Yu Zhang, Yijun Zhao, Shaozeng Sun,* Guozhang Chang, Xiaoyong Lai, Heping Tan, and Yukun Qin Cite This: Energy Fuels 2020, 34, 10583−10606
It does a better job of both introducing biochar - and providing new economic analysis.justification than I can recall from the last few years. And especially because from and about China - now clearly the world leader in biochar activity of all kinds Unfortunately still behind a paywall - but I believe well worth while finding a copy at local library or checking with friends.
2. Below I give a briefly-annotated outline of this paper - as the shortest way to explain how much is covered. I’ve written with the intent to encourage future list dialog and to promote biochar - as I think his paper also does (and is rare in technical papers). I don’t give more of the abstract as that is available at:
ABSTRACT: “As the world’s largest energy consumer (i.e., 24% of the world) and one of the largest biomass resource reserve countries (i.e., total reserves of 73.42 × 108 t a−1), for China, using biomass to prepare for biochar and store it in soil to realize the “carbon sequestration and emission reduction” is of great significance. …..
……. Finally, the existing bottlenecks of the technology are analyzed; the corresponding prospects are put forward; and the existing biomass utilization balance issues are discussed.”
1. INTRODUCTION (4.1 pages, 10 figures, 3 Tables, first 78 cites)
1.1. Current Status of Biomass Resources in China.
1.2. Carbon Fixation Effect of Biochar.
1.2.1. Definition of Biochar.
1.2.2. Carbon Sequestration Potential of Soil Carbon Pool.
1.2.3. Biochar Carbon Fixation Technology.
1.3. Research Status of Biochar Carbon Fixation and Emission Reduction.
“In 2007, Lehmann45 calculated that global biomass resources could achieve a CO2e emission reduction capacity of 1.28−1.36 × 109 t a−1 and forecasted that it could reach 20.1−34.9 × 109 t a−1 by 2100. ………..view [RW
[RWL1a: Very aggressive and not usually quoted - in line with their thinking. perhaps. This paper is probably the best I have seen for justifying large future biochar use. I have not yet read it twice - but have been pleased to learn a bit more about biochar research happenings in China.]
1.4. Research Methods.
“On the basis of the physical/ chemical characteristics of biochar, this paper explores the micro-principles and macro-effects of carbon sequestration and …..
…….The economic gap is calculated, to obtain the strength of requiring government subsidies.
[RWL1b: Pretty rare to see economics in biochar papers! This would be a worthy biochar summary paper if they stopped here. But this first section all apparently mostly meant to justify choices in the last half of the paper. - but there are some nice figures and tables I have not seen elsewhere.
2. CARBON SEQUESTRATION AND EMISSION REDUCTION: BIOCHAR CHARACTERISTICS (4.5 pages, 3 Easy equations; 4 Figures, 3 Tables, Cites 79-142)
2.1. Biochar Structure and Physical and Chemical Properties.
2.1.1. Structural Characteristics of Biochar.
2.1.2. Physical/Chemical Properties of Biochar.
220.127.116.11. High pH.
18.104.22.168. Surface Functional Groups.
22.214.171.124. Cation-Exchange Capacity (CEC).
2.1.3. Influencing Factors.
2.2. Preparation Method of Biochar.
2.3. Stability of Biochar.
2.4. Carbon Sequestration and Emission Reduction of Biochar.
2.4.1. Impact of Biochar Properties.
2.4.2. Effect of the Application Rate on the Application Effect.
2.4.3. Influence of Soil Factors.
2.4.4. Management Measures for Carbon Sequestration and Emission Reduction.
[RWL2 A continuation of Section 1’s preparation for the following sections. Again could be a paper all by itself.
3. BIOCHAR CARBON FIXATION AND REDUCTION POTENTIAL ASSESSMENT
(5 Pages, 5 more easy equations, Figures 14-17 , Tables 6-9 - all for the model, No new cites.)
3.1. Assessment Method.
3.2. Model Building.
3.2.1. Energy Balance and Green- house Gas Balance.
3.2.3. Plant Construction and Application Model.
3.3. Evaluation Results and Discussion.
3.3.1. Energy Balance.
3.2.2. Biochar Yield Model.
3.3.2. CO2e Balance.
3.4. Analysis of Carbon Sequestration and Emission Reduction Results.
[RWL3: I like the way this last half of the paper is basically a detailed description of a spread sheet. No need here for any new citations. They refer to earlier Life Cycle Assessments (LCAs) and build on them. If anyone can supply their spread sheet, that can save us all a lot of time. I have not yet checked it at all - but the results (with one exception) all look reasonable.
4. ECONOMIC FEASIBILITY ANALYSIS. (1.5 pages; Equations 9-14 are all easy; Table 10 with 16 assumption lines and Table 11 with 17 final spread sheet results - ending at line #92, )
4.1. Economic Evaluation Method.
4.2. Economic Evaluation Model
4.2.1. Pyrolysis Plant Evaluation Model.
4.2.2. Farmer Income Evaluation Model
4.2.3. Some Basic Assumptions.
4.3. Evaluation Results and Discussion.
[RWL4: Quite easy to follow - and ALL of the assumptions and method are here. I’ll come back later to a concern I have for not giving enough credit to improved NPP . They may have under-sold biochar.
5. FUTURE RESEARCH PERSPECTIVES (1.5 pages, No new figures, tables, or cites)
5.2. Problem Analysis.
5.3. Other Considerations.
[RWL5: A good list for our future discussion. As noted above, I’d like to see more on biochar’s benefits over 30 and/or 100 years. And how best to do financial discounting for farmers?
6. CONCLUSION ( 1/2 page)
(1) Reasons for carbon sequestration and emission reduction of biochar:
(2) Benefits of carbon fixation and emission reduction from different raw materials:
(3) Economic evaluation of biochar carbon fixation and emission reduction:
[RWL6: In a subsequent comment, I’ll give this final section in its entirety. This paper-recommendation is already too long. Again - a very rare combination of background, LCA with pricing, and China.
REFERENCES (142). (RWLr : A good selection - especially on LCAs and biochar financials)
Again apologies for length. Looking forward to other thoughts on the paper.