Lithium Supply Chain Optimization: A Global Analysis of Critical Minerals for Batteries
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis article discusses current and important issues related to optimizing the lithium supply mechanism to build an efficient energy storage system.
In recent decades, significant qualitative changes have occurred in the composition and structure of electric power systems (energy systems). First of all, this is due to a significant and steadily increasing share of generation using renewable energy sources and the development of distributed generation. Considering the stochastic nature of renewable energy sources - generation, its complete dependence on weather conditions, as well as due to the unstable nature of electricity consumption throughout the day, to guarantee a power balance, an appropriate amount of reserve power is required, which is currently implemented mainly through traditional generation.
High demand for lithium is a global trend driven by the rapid development of electric transport, primarily in China. Supply has not yet kept pace with demand. In addition, due to the experience of the pandemic and anti-Russian sanctions, there are concerns about the safety of the supply chain. As a result, there will be a sharp increase in lithium prices in 2022. In mid-November 2022, the lithium price reached an all-time high of $84,500 per ton. For comparison, in 2018, lithium cost an average of $25,000 per ton, and in 2020 the price fell below $6,000 per ton. The price of spodumene (a lithium-containing mineral from which lithium hydroxide and carbonate are produced) increased from $598 per ton in 2021 to $2,730 in 2022. In mid-September 2022, the price exceeded $7,800 per ton. Lithium-ion batteries have become the main technological elements of energy storage systems for electric vehicles and renewable energy networks. The resources and technologies required for their production and implementation will determine the leaders of the energy transition economy, which is very different from the modern energy consumption economy.
The results obtained in the article are of undoubted interest to readers in the field under consideration.
However, there are the following issues that should be clarified:
1. The article could provide a comprehensive diagram of the location of lithium deposits in various regions of the world in order to more clearly outline the problem being solved with the presentation of the corresponding projected values of lithium production in the future, which is of great importance for the development of the production of electric vehicles, the efficient operation of nuclear power plants and in general to create energy storage systems.
2. In section “2.2. Energy Storage Potential for Climate Mitigation” could list the main sources of carbon dioxide emissions into the atmosphere. In particular, show the impact of the mining industry, in particular coal mines, on greenhouse gas emissions.
3. In section “2.3.1. Lithium-Ion" it would be possible to consider the main factors affecting the service life of batteries, such as charge and discharge currents, self-discharge current, temperature, number of cycles, depth of discharge, operating range of charge level, etc. when modeling the real movement process (https://doi.org/10.3390/en14238072, https://doi.org/10.1016/j.est.2024.110580).
4. The technological supply chain of lithium should be presented in the form of a diagram (section “2.5. Lithium Supply Chain”) to make it more clear how lithium supplies will then be optimized.
5. It is necessary to dwell in more detail on the software used for the experimental results.
6. Based on the dependencies presented in the figures, a regression analysis should be carried out with the presentation of specific mathematical models that allow the calculation and forecasting of carbon dioxide emissions. It should also be explained how the predicted values were obtained and whether machine learning methods based on the use of artificial intelligence were used.
7. A generalized methodology for considering different lithium supply scenarios should be presented that could be patented and that could be applied to similar studies in other regions of the world.
8. In section “5.1. Future Work" it was possible to present proposals for further research on the study of technological supply chains for specific types of minerals in various regions of the world.
Author Response
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Author Response File: 
Author Response.docx
Reviewer 2 Report
Comments and Suggestions for AuthorsThe author should consider the below comments to improve the paper.
1. The abstract should be enriched with numerical data and findings of the study. In the current form, as structure and content, the abstract is more appropriate for a review paper than for a research article (as it is).
2. From a similar perspective as in the previous comment I recommend that sections 1 and 2 should be united and condensed. There are too many literature information but less discussion on what did the authors do different to emphasize the novelty of the study. It is very important to present a solid background for the study by applying a comprehensive literature review but this is not a REVIEW paper it is a research paper...Please reduce this part of the manuscript.
3. Please add some references to the text defined in the introduction section. Currently there are none...
4. The first two paragraphs from the methods section should be integrated into the introduction section or deleted because they present a literature review which is not required to define the applied methodology.
5. I my opinion in the figures the units on y axes should be removed and added instead to the legend of the figures to ease the identification and understanding of the represented data.
6. In the notations please modify the subscript “,t,t” which is confusing.
7. In my opinion there are too many figures. Maybe some should be converted in tables.
8. It seems that captions for figures 5,6. does not correspond to the content of the figures?!
9. Please insert a list of abbreviations and nomenclature which would be useful considering the notations and equations used in the paper. Please specify the unit of measurement for all parameters defined in the equations in accordance with SI.
10. In conclusion section numerical data should be added as well.
Comments on the Quality of English Language
Author Response
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Author Response File: Author Response.docx
Reviewer 3 Report
Comments and Suggestions for AuthorsThis work develops a mixed integer programming framework to optimize critical mineral supply chains for clean energy technologies, with a focus on lithium for EVs. It examines various aspects of the supply chain and presents scenarios comparing costs and emissions. Despite assumptions of perfect knowledge, trade-offs persist, suggesting real-world decision-making complexities. However, the framework offers scalable analysis and aids decision-makers in understanding and navigating supply chain dynamics. Overall, it provides valuable insights into the intersection of energy storage, critical minerals, and climate mitigation. In my opinion, the work is worth publication on this journal after addressing the following major revisions:
1. Too much description in background, too detailed, because this manuscript is an Article, so it needs to be streamlined.
2. Why is the starting year for Total Production by Year and Stage 2020, when it would be better to have the data 10 years earlier?
3. What is the significance of the data in Figure 4 Mine: Production by Technology? and does the curve need to be smoothed?
4. From figure 5, is the range of data from 2020-2100 too wide, and can the above problem be completely solved with the development of nuclear miniaturisation technology in the next 20 years?
Author Response
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Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors have made the necessary changes, I recommend the article for publication.
