Environmental and Social Impacts of Renewable Energy-Driven Centralized Heating/Cooling Systems: A Comparison with Conventional Fossil Fuel-Based Systems

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In the manuscript entitled “Environmental and social impacts of renewable energy-driven centralized heating/cooling systems: a comparison with conventional fossil fuel-based systems”. The authors assessed RES-integrated district heating in Bucharest, Luleå, and Córdoba. Results revealed a 67% reduction in greenhouse gas emissions but increased mineral resource use. Socially, local employment and safety improved, yet wage disparities and inadequate inclusion of vulnerable groups remained, which highlighted the need for governance that harmonized environmental and social objectives. This manuscript can be published in “Energies” after major revisions. The authors should refer to the following comments:

1. The treatment of the “avoided burden” in environmental outcomes required further elaboration, particularly regarding the rationale behind the negative carbon footprint in the Luleå case. It is recommended to discuss its methodological limitations and practical implications.
2. The manuscript contained an error in section numbering, where Section 3.1.1 was incorrectly followed by Section 3.4.2. This should be revised and reordered according to the manuscript content.
3. The S-LCA results relied heavily on qualitative descriptions and lacked quantitative support. It is recommended to try using a weighted or scoring system to convert qualitative data into comparable numerical values.
4. The description of data sources lacked transparency, particularly for subjective indicators such as “perceived improvement” in the S-LCA. And the manuscript proposed specifying the data collection tools, sample size, and response rate to enhance the credibility of the results.
5. The manuscript mentioned the indicators of “consumer health” and “information transparency” in the S-LCA section, but did not explain how the data was obtained. It is recommended that the authors clarify the source of the data.
6. In the Córdoba case, the metal consumption of renewable energy systems in the manuscript was 4.2 times that of fossil systems, but the proportion of key metals was not specified. It is recommended that the authors to supplement.
7. The manuscript mentioned in the conclusion section that “renewable energy systems reduce 63% -67% of carbon emissions” but did not mention that this benefit relies on “avoiding the burden of grid electricity”. It is recommended that the authors supplement this.
8. The manuscript proposed a circular economy strategy to address the “metal resource pressure”, but the suggestions were relatively general. It is recommended that the authors be specific.
9. There is a formatting error in the reference section of the manuscript. It is recommended that the authors check the entire text and make revisions.

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Is there a weight reason which explains why in only two of three assess scenarios WEDISTRICT + avoided burden condition is considered?  Why not in all conditions??

Just please, let me suggest some ideas to be considered when results are presented. It´ll be grateful if quality of images 1 to 3 would be increase.  Graphs must be clearer than presented. Ordinate axes present no legend in figure 4 and figure 6, it would be clearer for readers if adequate legends are included. It can be noticing a mixture from coma and point to separate decimals number in tables. There is a homogeneity lack when graphs are presented, in figure 4, labels under baseline are presented, not in other 5 or 6.

In lines

82 references must be included

99 TRL capitals must be described

145 Redundat leyend after number two presentation

164 Is there a reason to explain why only indicator selection are considered and not all ones available?

324  Acidification units are H⁺ with superindex of +

 

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

In my opinion, the proposed paper in its current form offers a lot of text of very limited and uncertain added value.

First of all, it suggests an analysis of “RES-powered DHC solutions” while in practice, it focuses on solutions which are local and limited to a small group of buildings. It should be precisely defined in the abstract and the introduction.

The title and abstract suggest an analysis focused on RES solutions, whereas the demo sites are actually hybrid solutions that still use fossil fuels. In addition to RES, waste heat recovery is considered.

Table 1, with the case scenarios definition, is difficult to read. It would be better to define the study cases in plain text.

Figures 1, 2 and 3 are very generic and insufficiently support the methodology. For example, mass and energy flows are not sufficiently defined, and the control volume of the studied systems is not depicted. Therefore, it is not possible to understand the Functional unit (FU) definition. Moreover, the calculation scheme and relevant mass and energy balances are not presented in the methodology section. For example, it is not known if the “1kWh of energy delivered to the system” is heat, cold or electricity, and where is the entry point. In my opinion, the calculations should be supported by clearly defined equations.

Results presented in tables 8 to 11 cannot be verified nor appropriately interpreted do to the weakly presented methodological approach.

In my opinion conclusions are very generic. Some parts can be deleted, and some should be moved to the discussion section. The conclusions should focus on the actual value of the results and their further use (e.g. recommendations for policy shaping).

Author Response

Please see the attachment

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have addressed all of my comments. I would recommend it for publication.

Reviewer 3 Report

Comments and Suggestions for Authors

In my opinion the text has been sufficiently improved and in th ecurrent version can be considered for publishing in Energies. It provides interesting insights from demo sites, and shows how the society can benefit from different heating and cooling soultions.