Quantitative Assessment of Coal Phaseouts and Retrofit Deployments for Low-Carbon Transition Pathways in China’s Coal Power Sector

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1.The title 'Coal Power Transition' can be more specific, for example, changed to 'Low Carbon Transition Pathways for China's Coal Power Sector' to more accurately reflect the research content. The abstract section can be further streamlined to highlight the core findings (emission reduction potential) and key methods (multi criteria evaluation framework), avoiding excessive technical details.
2. Transparency of data sources, with multiple references to databases (such as Global Coal Power Tracker, EDGAR) in the article but no specific access links or DOIs provided. Suggest supplementing complete data source information, such as clearly indicating the availability of the dataset in the references, or adding appendices to explain the data acquisition method.
3. The color differentiation of the legend in Chart Optimization Figure 3 (Provincial Carbon Emissions and Capacity Distribution) is insufficient. It is recommended to use a brighter color scale or add annotations.
4.The layout of Table 1 (Unit Classification) is too dense and can be split or switched to a horizontal layout to improve readability.
5. It is recommended to directly indicate the time range in the title of the year label (2025-2032) in Figure 8 (Technology Deployment Forecast) to avoid readers misunderstanding it as a single year.
6.Section 4.1 only mentions a 0.63% uncertainty in the sensitivity analysis of weight allocation, but does not discuss its actual impact on policy-making. Suggest adding specific cases (such as changes in the priority retirement sequence of units in a certain province) to enhance practicality.
7. More specific policy recommendations can be added to the conclusion, such as proposing a regional collaborative retirement mechanism for small capacity units (<300 MW). Emphasize the key role of reducing the cost of green hydrogen in ammonia co combustion technology, and suggest that the government subsidize pilot projects. Supplement the financing model for the large-scale deployment of CCUS.

Comments on the Quality of English Language

The English could be improved to more clearly express the research.

Author Response

Please find the revision in the attachment.

 

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

General comments:

The paper proposes an integrated data-driven framework to support the low-carbon transition of China’s coal power industry, covering strategies for unit retirement, new construction, and retrofitting, while quantifying emission reduction potential and costs based on scenario analysis. The study holds practical policy reference value, but certain sections require further refinement and substantiation. It is recommended to revise and resubmit.

 

Detailed comments and suggestions:

 

 

1. The abstract needs to be condensed to emphasize core contributions. The current abstract is lengthy. It is recommended to streamline it and clearly outline the following points: the proposed innovative framework (e.g., "integration of unit-level databases and multi-criteria evaluation methods"), key results (emission reductions, costs, technological contributions), and scientific value (e.g., "providing policymakers with dynamic planning tools").

 

2. In the Introduction, the final paragraph clarifies the study’s objectives but is overly verbose. It is suggested to use more concise language, for example: "This study aims to develop an integrated framework to coordinate unit retirement, new construction, and retrofitting strategies, quantifying emission reduction pathways and cost-effectiveness under different scenarios."

 

3. In Section 3.2 (Analysis of Carbon Emissions), when decomposing emission reduction mechanisms (M1-M3), it is necessary to compare findings with related studies and highlight this study’s distinctions.

 

4. In Table 2, the use of both "gce/kWh" and "%" units for the same technical metrics is inconsistent. It is recommended to unify the units. The same applies to Table 3.

 

5. In Figure 3(b), excessive annotations hinder readability. It is suggested to consolidate labels for certain unit types.

Author Response

Please find the revision in the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

This is comprehensive assessment analysis on the coal power unit transition under the carbon policy. In general, the structure was well organized and status was deeply and quantitatively  calculated. It can be accepted after minor revision. 

1: as an international submission, the authors are encouraged to discuss the relation between the coal power transition in Chinese market and the international side. this will be helpful  to attract more attention of readers outside China. 

2: in figure 4, add legend to the different colors

 3: figure 11, please give more expression how to compare the normalized data with 3D figure?
such as the data at 0.5,0.5 0.5, what is the meaning of this point?

4: for the natural retirement units, how many such units in China, after 2000, more new units were constructed in China, some small scale units, still in lifespan, have to be stopped  due to policy, not technical reason. 

Author Response

Please find the revision in the attachment.

Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

The paper is well written and well organized.

It introduces a hot topic on Assessment of Coal Phaseouts in China, which contributes around 32% of total emissions in 2024.

Also the problem formulation is presented in a comprehensive manner. I think few points need to be enhanced in the revised version.

1-There are many symbols in the paper and many abbreviations. Please add a list of symbols and list of abbreviations.

2-The conclusion section recommended to be enhanced with study limitations specially the economic effect.

3- Resolution of some figures to be enhanced.

Author Response

Please find the revision in that attachment.

Author Response File: Author Response.docx

Reviewer 5 Report

Comments and Suggestions for Authors

This paper presents a comprehensive analytical framework to support China’s low-carbon transition by combining phased retirement, greenfield construction, and retrofitting. We use an updated unit-level database (4708 units) and a multi-criteria assessment to plan plant retirements, taking into account natural aging (lifespan 25–40 years) and policy constraints (e.g. heating radius). The BCNS and ICNS scenarios based on the China Energy Transformation Outlook (2024) project coal-fired generation capacity curtailment to 299.5 GW (BCNS) and 287 GW (ICNS) by 2060. Optimizing the technology portfolios (T1–T11) through LCOC minimization reveals that CCUS and co-firing provide 52.9–61.3% of the emission reductions (10–14.9 GtCO₂), but require 65–76% of the retrofit investment. The total cost of the transition is estimated at CNY 6.2–6.7 trillion, with 64–66% going to renewable energy. Sensitivity analysis confirmed the robustness of the methodology (error <0.63% for mitigation potential). The critical factor was identified as the reduction in the cost of green hydrogen for ammonia co-firing. However, regional cost heterogeneity and regulatory risks could be taken into account, which requires further research.

 

However, the work has the following comments:

 

1. The article lacks a detailed comparison of the proposed scenarios (BCNS and ICNS) with similar studies in other countries, which reduces the value of the findings for an international audience.
2. The initial data for modeling (e.g. emission factors, technology parameters) should be described in more detail.
3. The simulated annealing algorithm is mentioned, but its parameters (temperature, cooling rate) are not disclosed, which is important for assessing the reliability of the optimization.
4. The work should focus on the principles of the circular economy. In particular, the demonstration of cross-sector synergies for carbon neutrality seems interesting (https://doi.org/10.1016/j.ijpe.2024.109178, https://doi.org/10.1016/j.rcradv.2024.200224). A section on "Cross-sectoral Synergies" could be added to enhance the practical relevance of the work.
5. It is not specified which software was used for data processing and visualization (e.g. Python, MATLAB).
6. For technologies T9-T11 (CCUS, co-firing), no experimental data or references to pilot plants confirming the declared parameters are provided.
7. In section 4.1, the sensitivity analysis is only performed for 2036, which is insufficient to assess the sustainability of the model in the long term.
8. An error estimate for key indicators should be provided (e.g. ±X% for LCOC).
9. Regional differences in the cost of implementing technologies are not taken into account (e.g. CCUS in coastal inland areas).
10. Implementation barriers (e.g. regulatory risks for green ammonia) and possible compensation mechanisms are not discussed.

Author Response

Please find the revision in the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 5 Report

Comments and Suggestions for Authors

All comments have been corrected. I recommend the article for publication in the form presented.