An Overview of Waste-to-Energy Incineration Integrated with Carbon Capture Utilization or Storage Retrofit Application

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In the manuscript entitled “An overview of Waste-to-Energy incineration integrated with Carbon Capture Utilization or Storage retrofit application”, the authors have tried to summarise and report an overview of the integration of Carbon Capture, Utilization or Storage (CCUS) technologies with waste-to-Energy (WtE) incineration plants in retrofit applications. While this topic can attract the interest of the Sustainability readers, there are some issues that should be addressed, as follows:

1.     What is the most significant difference between the current review and other published ones?

2.     The authors should explain the current and newly developed CCS technologies in detail.

3.     The authors should explain the current and newly developed CCU technologies in detail.

4.     The economical aspect should also be considered since CCUS are not cheap and easily accessible.

5.     Add a recommendation for future study and solution to current limitations.

Comments on the Quality of English Language

Need English language editing.

Author Response

Rebuttal of the Manuscript: “An overview of Waste-to-Energy incineration integrated with Carbon Capture Utilization or Storage retrofit application.”

 

Michele Bertone, Luca Stabile, and Giorgio Buonanno.

 

We sincerely thank the reviewer for the thorough review and valuable comments on our manuscript. In response, we have carefully considered each comment and have accordingly made substantive modifications to our manuscript. Below, we provide a detailed point-by-point response to the reviewer’s comments, including references to the specific changes made in the revision. We hope that these revisions adequately address the concerns raised and that our manuscript is now deemed suitable for publication in the journal Sustainability.

 

In the manuscript entitled “An overview of Waste-to-Energy incineration integrated with Carbon Capture Utilization or Storage retrofit application”, the authors have tried to summarise and report an overview of the integration of Carbon Capture, Utilization or Storage (CCUS) technologies with waste-to-Energy (WtE) incineration plants in retrofit applications. While this topic can attract the interest of the Sustainability readers, there are some issues that should be addressed, as follows:

 

1. Comment: What is the most significant difference between the current review and other published ones?

Response: Following your comment, we have expanded the Introduction Section in order to define our research in the context of existing literature. Our review differs from previous publications in its focused approach toward presenting all aspects related to the integration of CO₂ capture technologies in existing WtE plants. Our work highlights that the integration of capture technologies is not only a technical and economic issue but is also linked to the availability of a developed CO₂ market that can receive part of the captured CO₂ and the presence of suitable permanent storage. Additionally, our study explores the differences between different countries in adopting such technologies. For instance, in the Netherlands, the presence of a well-developed CO₂ market and proactive sustainability policies have opened the way for the integration of CO₂ capture and utilization systems in their WtE plants. Conversely, in Italy, the absence of a developed CO₂ market and permanent storage infrastructure presents a significant barrier.

 

2. Comment 2 and Comment 3: The authors should explain the current and newly developed CCS technologies in detail. The authors should explain the current and newly developed CCU technologies in detail.

Response: We have revised our manuscript to provide a more detailed discussion of post-combustion capture technologies in Section 5.1 and an extended storage analysis in Section 5.4. Regarding post-combustion technologies, we have included physical methods, such as membrane separation, cryogenic condensation and physical absorption, and chemical methods, such as chemical absorption. We have explained why certain technologies may not be ideal for CO₂ capture from flue gases in WtE plants. Regarding Storage, we have extended the discussion to cover the entire storage process, including CO₂ conditioning, transport, and permanent storage. Regarding Utilization, we have made slight modifications to better distinguish between direct use and indirect (conversion) uses of captured CO₂ in Section 5.3. However, we would like to clarify that we do not go into specific technologies in detail, as this goes beyond the scope of this article. Our goal is to provide a broader perspective that considers the complexities, regulatory framework, and differences between countries (mainly The Netherlands and Italy), regardless of the specific destination of CO₂ captured.

 

3. Comment: The economical aspect should also be considered since CCUS are not cheap and easily accessible.

Response: Our paper focuses on the integration of CCUS within WtE frameworks, primarily examining the regulatory, technical, and infrastructural challenges involved. Although the economic perspective is significant, it is not within the primary scope of this review and should be analyzed (as now stated in the conclusions) in future works.

 

4. Comment: Add a recommendation for future study and solution to current limitations.

Response: As mentioned in the previous comment, we have now highlighted in the conclusions that the paper is focused on the integration of CCUS within WtE frameworks from a regulatory, technical, and infrastructural points of view. No details from the economic perspective were provided. Future studies should be focused on the economic criticalities in order to provide an overall evaluation of the issue of integrating CCUS within WtE.

 

In order to increase the readability of the revised version of the paper, all the modifications have been clearly evidenced in the “red” color.

We hope that all the referee’s comments have been well addressed through the modifications made to the paper.

 

Kind regards,

Michele Bertone

Reviewer 2 Report

Comments and Suggestions for Authors

1. "Affiliation 2" in line 6 may be an error that needs to be deleted, please check.

2. Please note the subscript of "CO2" in line 12, 16， and carefully review it throughout the entire manuscript（Especially in the references）.

3.  “left，middle and right” in line 226-227 can be replaced by "(a), (b), (c)" inserted in figure 1. 

4. Why "Figure 2" in line 239 bolded， but "Figure 1, Figure 3, Figure 4" in line 217, 251 284 not? Please check the same issue in "Table 1, Table 2 and Table 3"

5. The font in Table 1 is too large than that in other table.

6. "Figure 4" in line 289 and "Table 3" in 414 should be bold.

7. Line style of Table 1-3 is inconsistent and inappropriate. Please use unified format, such as a three line table.

8. Is it normal that Figures 2 and 3 are not referenced? Please check.

9. The technical details and characteristic regarding CCUS, CCU, and CCS need to be further enriched. What's the advantages of CCUS over other technology, please provide a specific and concise explanation.

10. Missing '.' in the end of line 384.

11. Indent the first line by 2 characters （line 459）.

Comments on the Quality of English Language

The professionalism of language need to be improved. 

Some text, figure and table formatting issues should be given attention.

Author Response

Rebuttal of the Manuscript: “An overview of Waste-to-Energy incineration integrated with Carbon Capture Utilization or Storage retrofit application.”

 

Michele Bertone, Luca Stabile, and Giorgio Buonanno.

 

We sincerely thank the reviewer for the thorough review and valuable comments on our manuscript. In response, we have carefully considered each comment and have accordingly made substantive modifications to our manuscript. Below, we provide a detailed point-by-point response to the reviewer’s comments, including references to the specific changes made in the revision. We hope that these revisions adequately address the concerns raised and that our manuscript is now deemed suitable for publication in the journal Sustainability.

 

1. Comment: "Affiliation 2" in line 6 may be an error that needs to be deleted, please check.

Response: "Affiliation 2" was an error and has been removed from the manuscript.

 

2. Comment: Please note the subscript of "CO2" in lines 12 and 16 and carefully review it throughout the entire manuscript (Especially in the references).

Response: Thank you for pointing this out. We have carefully reviewed and corrected the subscript formatting for "CO2" throughout the entire manuscript, including references.

 

3. Comment: “left, middle and right” in line 226-227 can be replaced by "(a), (b), (c)" inserted in figure 1. 

Response: Based on your suggestion, we have removed “left, middle, and right” in the description of Figure 1.

 

4. Comment: Why "Figure 2" in line 239 bolded, but "Figure 1, Figure 3, Figure 4" in line 217, 251 284 not? Please check the same issue in "Table 1, Table 2 and Table 3".

Response: This inconsistency was a mistake. We have standardized the formatting across all references to figures and tables in the text.

 

5. Comment: The font in Table 1 is too large than that in other table.

Response: We adjusted the font size in Table 1 to match that of other tables.

 

6. Comment: "Figure 4" in line 289 and "Table 3" in 414 should be bold.

Response: "Figure 4" and "Table 3" have now been bolded in the manuscript.

 

7. Comment: Line style of Table 1-3 is inconsistent and inappropriate. Please use unified format, such as a three line table.

Response: We have revised Tables 1-3 to a unified three-line table format.

 

8. Comment: Is it normal that Figures 2 and 3 are not referenced? Please check.

Response: We added a reference to Figure 2, but did not add one to Figure 3 as it was prepared without a reference.

 

9. Comment: The technical details and characteristics regarding CCUS, CCU, and CCS need to be further enriched. What's the advantages of CCUS over other technology, please provide a specific and concise explanation.

Response:  We have expanded Section 5 of our paper to provide a more detailed discussion on post-combustion capture technologies (Section 5.1) and Storage (Section 5.4) or Utilization (Section 5.3). Regarding post-combustion technologies, we have included physical methods, such as membrane separation, cryogenic condensation, and physical absorption, and chemical methods, such as chemical absorption. We have explained why certain technologies may not be ideal for CO₂ capture from flue gases in WtE plants. Regarding Storage, we have extended the discussion to cover the entire storage process, including CO₂ conditioning, transport, and permanent storage. Regarding Utilization, we have made slight modifications to better distinguish between direct use and indirect (conversion) uses of captured CO₂. However, we would like to clarify that we do not delve into specific technologies in detail, as this goes beyond the scope of this article. We made this choice because the aim of this work is to provide an overview of the integration of CCUS technologies into the WtE incineration plant, showing that it is a complex issue that involves technical, regulatory, and economic considerations. To achieve success, it is necessary to understand not only the technical and economic aspects but also the regulatory frameworks, applicable incentives, and the CO₂ market (especially in terms of tons), within the host country, as described in the introduction paragraph.

 

10. Comment: Missing '.' in the end of line 384.

Response: The missing period at the end of line 384 has been added.

 

11. Comment: Indent the first line by 2 characters (line 459).

Response: We have added an indent to the first line by 2 characters as suggested.

 

In order to increase the readability of the revised version of the paper, all the modifications have been clearly evidenced in the “red” color.

We hope that all the referee’s comments have been well addressed through the modifications made to the paper.

 

Kind regards,

Michele Bertone

Reviewer 3 Report

Comments and Suggestions for Authors

This manuscript has a clear, logical structure and rigorous research methods. It introduces the basic principles of WtE incineration and CCUS technology and discusses the integration of CCUS technology with WtE incineration technology. It also provides a list of the current application status of this technology. This manuscript is informative and can serve as a reference for advancing the practical industrial application of CCUS technology. However, it should be slightly revised before publication.

1.      Section 2 introduces the basic principles of waste incineration power generation but lacks an overview of the waste incineration power generation process. It would be helpful to provide a visual representation similar to Figure 3, which illustrates the process flow.

2.      Similar to question 1, sections 3 and 4 only contain textual descriptions and lack corresponding tables and images. For example, in section 3, the carbon emissions and their proportions from fossil fuel combustion can be better illustrated using a table. Relying solely on textual descriptions is not conducive to readability.

3.      The manuscript only mentions the amine-based chemical absorption method when discussing carbon capture technology, which is entirely one-sided. In the field of chemical absorption, there are also efficient ionic liquid absorbents and phase-change absorbents. Additionally, solid CO₂ adsorbents have been extensively researched in recent years. Surprisingly, none of these carbon capture technologies are mentioned in this manuscript.

Similarly to question 3, section 5.3 only discusses the direct utilization of captured CO₂. However, it is crucial not to overlook that CO₂, as a high-quality carbon source, can be converted into economically valuable products through various pathways, such as methane, syngas, methanol, etc. Unfortunately, this manuscript also fails to mention these crucial aspects.

Comments on the Quality of English Language

Minor editing of English language required

Author Response

Rebuttal of the Manuscript: “An overview of Waste-to-Energy incineration integrated with Carbon Capture Utilization or Storage retrofit application.”

 

Michele Bertone, Luca Stabile, and Giorgio Buonanno.

 

We sincerely thank the reviewer for the thorough review and valuable comments on our manuscript. In response, we have carefully considered each comment and have accordingly made substantive modifications to our manuscript. Below, we provide a detailed point-by-point response to the reviewer’s comments, including references to the specific changes made in the revision. We hope that these revisions adequately address the concerns raised and that our manuscript is now deemed suitable for publication in the journal Sustainability.

 

This manuscript has a clear, logical structure and rigorous research methods. It introduces the basic principles of WtE incineration and CCUS technology and discusses the integration of CCUS technology with WtE incineration technology. It also provides a list of the current application status of this technology. This manuscript is informative and can serve as a reference for advancing the practical industrial application of CCUS technology. However, it should be slightly revised before publication.

 

1. Comment: Section 2 introduces the basic principles of waste incineration power generation but lacks an overview of the waste incineration power generation process. It would be helpful to provide a visual representation similar to Figure 3, which illustrates the process flow.

Response: We have added Figure 1 to Section 2, which visually represents the waste incineration power generation process. Along with this figure, we have also added a description to help readers understand the process.

 

2. Comment: Similar to question 1, sections 3 and 4 only contain textual descriptions and lack corresponding tables and images. For example, in section 3, the carbon emissions and their proportions from fossil fuel combustion can be better illustrated using a table. Relying solely on textual descriptions is not conducive to readability.

Response: As suggested by the reviewer, we have now included Table 1 in Section 4, which presents a clear summary of the directives and procedures in the regulatory framework section. Regarding Section 3, we have decided not to include any more figures as we believe that the existing textual descriptions are sufficient to explain the required information.

 

3. Comment: The manuscript only mentions the amine-based chemical absorption method when discussing carbon capture technology, which is entirely one-sided. In the field of chemical absorption, there are also efficient ionic liquid absorbents and phase-change absorbents. Additionally, solid CO₂ adsorbents have been extensively researched in recent years. Surprisingly, none of these carbon capture technologies are mentioned in this manuscript.

Response: Following your comment, we have expanded Section 5 to include a discussion on post-combustion capture technologies. We have also better explained the reason why specific technologies may not be suitable for CO₂ capture from flue gases in WtE plants.

 

4. Comment: Similarly to question 3, section 5.3 only discusses the direct utilization of captured CO₂. However, it is crucial not to overlook that CO2, as a high-quality carbon source, can be converted into economically valuable products through various pathways, such as methane, syngas, methanol, etc. Unfortunately, this manuscript also fails to mention these crucial aspects.

Response: Following your comment, we have made slight modifications to better distinguish between direct use and indirect (conversion) uses of captured CO₂ in Section 5.3. However, we would like to clarify that we do not go into specific technologies in detail, as this goes beyond the scope of this article. Indeed, the main aim of the paper is to provide a broader perspective considering the complexities and regulatory framework, independently of the specific destination of CO₂ captured. This aspect is now clearly explained in the Introduction section: “Given the large number of plants in Europe, exploring the integration of CCUS technologies with WtE incineration in retrofit applications becomes particularly interesting. However, integrating CCUS technologies into the WtE incineration plants is a complex issue involving technical, regulatory, and economic considerations. To be successful, it requires an understanding of the regulatory frameworks, applicable incentives, and CO₂ market (especially in terms of tons) within the host country. Some countries have already implemented this technology, like the Netherlands, whereas in most of the other countries worldwide, e.g. Italy, there are no examples of this implementation.”

 

In order to increase the readability of the revised version of the paper, all the modifications have been clearly evidenced in the “red” color.

We hope that all the referee’s comments have been well addressed through the modifications made to the paper.

 

Kind regards,

Michele Bertone

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The author has provided sufficient responses to the comments, and the manuscript can be accepted after minor modifications (especially references format).

Author Response

Rebuttal of the Manuscript: "An overview of Waste-to-Energy incineration integrated with Carbon Capture Utilization or Storage retrofit application."

Authors: Michele Bertone, Luca Stabile, and Giorgio Buonanno.

We thank the reviewer for the review on our manuscript. Regarding the request for minor modifications, we have carefully reviewed the manuscript and made necessary modifications to ensure that it complies with the journal's guidelines.