Transition Pathways for Low-Carbon Steel Manufacture in East Asia: The Role of Renewable Energy and Technological Collaboration

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper establishes a model to study the role of renewable energy and technological cooperation in the process of achieving near-zero-carbon transformation of the steel industry in China, Japan and South Korea. It examines the impacts of technological progress, resource endowments and policy support on the production of hydrogen-based direct reduced iron (H-DRI), and takes the Levelized Costs of Energy (LCOE), the Levelized Cost of Hydrogen (LCOH) and the Levelized Cost of Steel (LCOS) as the key indicators for evaluating the economic feasibility of steel production based on green hydrogen. At the same time, corresponding conclusions are drawn, which have certain guiding significance.

Meanwhile, there are still some aspects of this paper that need to be further improved. For details, please refer to the attachment.

Comments for author File: Comments.pdf

Author Response

Please provide a more detailed explanation of how the above factors affect the scenario setting in Table 1.	Revised. Renewable energy plays a critical role in shaping the scenario settings for H-DRI and EAF steel-making process. The cost of renewable energy largely depends on technological advancements. As these technologies mature, the cost of renewable energy is expected to decline significantly. By 2050, ISI is projected to achieve near-zero emissions, and the development of renewable energy technologies will be a critical factor influencing the cost of zero-carbon steel production. Varying degrees of technological progress will lead to different production pathways toward zero-carbon steel.
The raw materials for steel production are also of great importance and should be given attention.	Yes, since green hydrogen is the key raw material of the steel production, and it is produced from renewable energy. Renewable energy will be the basic for the production.
First of all, there is missing data in the table.   Secondly, the text mentions that Busan in South Korea, as well as the Tokyo Bay, Nagoya, and Hiroshima regions in Japan are the main steel production areas. Regarding the data of Japan and South Korea in this table, which specific region of each country do they correspond to, or are they the average values of the aforementioned regions?	Revised the table. Busan is located in South-West of Korea, and regions in Japan’s data is used the average one.
Are there appropriate and adequate references to related and previous work?
How does the calculation formula of LCOH reflect the two influencing factors of LOCE and operating efficiency?	Electricity cost (LCOE) is a dominant term in LCOH, and the operating efficiency impact the total production.
What does "Electricity" in the formula mean? What is the difference between it and the "Electricity" in Table 3?	Yes. “Electricity” means the total cost of electricity consumption, and in this study, the electricity cost is the LCOE.
Please provide a quantitative calculation formula.	Sorry Since the transportation data is from the website directly, there is no relevant formula.

 

Reviewer 2 Report

Comments and Suggestions for Authors

This paper has the potential to be accepted, but, in its current form, the paper has several shortcomings, as summarized as follows:

1) The introduction section of the research lacked a sufficient literature review. Which gap in the literature does this study intend to fill and what is its contribution to the literature?
Regrettably, I was unable to find an answer to these questions in the article.

2) Justification is required for the solution proposal. Idea are good, but the analyses are not in-depth.  What kind of innovation will be realised with the integration of offshore wind energy and hydrogen production technologies.

3) Although the paper's structure was determined to be adequate, a discussion should be included. Not enough discussion of the analysis presented in Figures in the article

4) Especially the references of the equations are incorrect, please fix them

Author Response

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

1) The introduction section of the research lacked a sufficient literature review. Which gap in the literature does this study intend to fill and what is its contribution to the literature?
Regrettably, I was unable to find an answer to these questions in the article.

The paper mentioned that: “there is a lack of detailed analysis on the potential for future zero-carbon steel production in China, Japan and South Korea, considering regional resource differences and international collaboration”.

 

 

2) Justification is required for the solution proposal. Idea are good, but the analyses are not in-depth.  What kind of innovation will be realised with the integration of offshore wind energy and hydrogen production technologies.

Thanks. This study estimates the Levelized Cost of Hydrogen (LCOH) for offshore wind in Japan and South Korea. Unlike previous studies, it considers the potential of importing equipment from China, and the results demonstrate its economic feasibility. Under future uncertainties regarding imported green products, this provides an alternative pathway for Japan and South Korea.

 

 

3) Although the paper's structure was determined to be adequate, a discussion should be included. Not enough discussion of the analysis presented in Figures in the article

 

Thank you, part 3 is the result and discussion. All the discussion are shown after all results.

4) Especially the references of the equations are incorrect, please fix them

Thanks, I fix the references.

 

Reviewer 3 Report

Comments and Suggestions for Authors

This paper discusses the transformation path of low-carbon steel manufacturing in East Asia, especially the economic feasibility of hydrogen based direct reduction iron (h-dri) technology, filling the gap in the analysis of resource differences among China, Japan and South Korea in the existing literature. However, before the paper is published, several questions are put forward to the author.

1. There is less discussion on "international technical cooperation" in the study. It is suggested to further specify the cooperation mechanism (such as policy coordination, technology sharing platform, etc.) and supplement case or data support to enhance the practical significance of the study.
2. The technical cost data quoted in this paper (such as wind power capex) is mainly based on the literature from 2020 to 2023, but some forecasts (such as the cost decline in 2025) lack recent empirical support. It is recommended to update the latest reported data of international agencies.
3. The research adopts levelized cost (Lcoe, Lcoh, LCOS) as the core index, and the method is reasonable, but the model assumption does not consider the energy storage problem and the coupling effect of electrolyzer and wind power. In the future, we can consider supplementing sensitivity analysis to explore the impact of these factors on the results.
4. Figure 1-3 shows the cost trends under different scenarios. Will the differentiation of relevant driving factors (such as labor costs and policy subsidies) affect the results?
5. The conclusion mentioned that China, Japan and the Republic of Korea should strengthen bilateral cooperation. Is it necessary to supplement relevant cooperation barriers (such as trade barriers and intellectual property issues)?
6. The marking of Figures 4 and 5 should be optimized. For example, the specific year should be clearly marked when comparing "local advanced" with "import". Some terms (such as "Dr grade iron ore") need to be defined when they first appear.

Author Response

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

2. Reply

2.1 There is less discussion on "international technical cooperation" in the study. It is suggested to further specify the cooperation mechanism (such as policy coordination, technology sharing platform, etc.) and supplement case or data support to enhance the practical significance of the study.

Reply: The article includes a discussion on the potential for international cooperation. However, this paper only explores the potential collaborative pathways for achieving zero-carbon production in the steel industries of Japan and South Korea from a technical perspective. The mechanisms for future cooperation will be further discussed in the next paper.

 

2.2 Add relevant references in the article, including the latest 2024 reports from BNEF, IRENA, and IEA

 

2.3 A sensitivity analysis could be considered for the future, but it will not be included in this paper.

2.4 In this study, labor costs are considered as part of the operational costs and have been thoroughly evaluated. After discussions with experts in the field, it is expected that labor involvement in the construction of wind farms and hydrogen production processes will significantly decrease in the future, thus having a limited impact on the cost structure. This section has also been incorporated into the discussion part.

2.5 Revised

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

All the comments are revised in the submitted manuscript. This paper can be accepted.

Author Response

All the comments are revised in the submitted manuscript.