Mapping the Energy Flows and GHG Emissions of a Medium-Size City: The Case of Valladolid (Spain)

Round 1

Reviewer 1 Report

The paper describes an evaluation of medium-size city decarbonization. It is potentially interesting, but it is poorly structured and poor written and it is too long. Many citations were not proper cited. Therefore, it requires a major revision to be evaluated fairly.  

Author Response

We have made a deep review of the paper to correct the issues that you pointed out. We have modified the structure of sections: the subsections in methodology part are reorganised, the result section only represents the results and we introduce new subsections in the Discussion section to compare with the literature and the state-of-the-art. Also, the longest parts in methodology section have been removed and replaced by two synthetic tables including the same information (Tables 1 and 2), in order to reduce the text length. For the sake of clarity, we include a new Figure 1 which depicts the workflow of the analysis. We have also done a style and English language corrections (by a professional English corrector, which is one of the reasons for the delay in the resubmission).

We believe that these changes enhance the paper and make easier to follow the research done. So, we thank the opportunity to make this improvement.

Reviewer 2 Report

1. You write that “we propose and apply a novel method to estimate the evolution of GHG emissions”. Later you indicate that you use an approach used by other researchers [16-18]. Thus, is the method (methodology) new? If not, what is the contribution and novelty of your research? What is the scientific problem (as it is a scientific paper)?
2. Another remark is related to the objective of your research. First, there cannot be two objectives (the main and a secondary). Second, the objective “to identify the main local energy flows” is too poor for a scientific paper.
3. Check numbering of sub-sections (there are several 1.1 and 1.1.1 sub-sections) and links to the tables or figures (Error! Reference source not found).
4. What is Ud units (Table 1)?
5. You write “To admit the hypothesis proposed, the CORES data [47] for the period 1997-2019 for the 53 Spanish provinces have been analysed” (page 10). What hypothesis do you mean?
6. You write “We obtained a strong correlation between the different oil products consumption for transport and the provincial population (R² > 0.88 for Gasoline…)”. Correlation coefficient is marked by r and R² is coefficient of determination. What is R² here?
7. You use lots of assumptions that can significantly change the results of your calculations, e.g. “Energy consumption due to urban mobility was calculated based on the mobility data collected in the 2015 mobility survey”, but mobility data can significantly change during the decade (2010-2019). To what extent the assumptions used in your research can change your final conclusion that the GHG reduction by 2019 was ~11% with relation to 2010?
8. Why 2016 is the central data for the decade (2010-2019) (page 14)?
9. I missed the authors’ recommendations how the exponential decrease of GHG emissions (~13%/year) till 2050 can be achieved.

Author Response

See point-by-point response in attachment. Many thanks for your review.

Author Response File: Author Response.pdf

Reviewer 3 Report

Main Comment

The model presented is novel and innovative method to estimate the evolution of GHG emissions due to energy consumption for the period 2010-2019 for the case of Valladolid, combining top-down and bottom-up data following a physical energy flows approach which is hallmark of the paper. The method steps are well described and mathematical concepts in graphs are described in good detail. Unfortunately, the manuscript with the current presentation is not publishable since a thorough english redo is necessary.

Author Response

Thank you for your remarks. We have done a style and English language corrections (by a professional English corrector, which is one of the reasons for the delay in the resubmission).

Round 2

Reviewer 1 Report

The paper has been improved. Please check the following two points. 

1. Tables have numbers with many digits, but effective digits should be smaller for the accuracy needed for the paper.
2. Annual decline rate of CO2 emission in %  should also be given with the number annual decline amount of CO2 emission. If you use ratios,  in earlier years you need to reduce a lot but later years very little. So, you can also provide number of average annual CO2 emission reduction amount to 2050. 

Author Response

Thank you very much for your comments.

Before starting, just a short explanation about the code used for replying:

• Replies: normal text.
• Text being originally in the manuscript: italic.
• Additions/changes to the text in the manuscript: italic+bold.

With relation to your two points:

1. We have reduced the number of digits in tables 5, 6 and 7.
2. We have also included the average annual reduction objective in the discussion part, so it shows the estimated reduction on average:

Reaching GHG neutrality in 2050 requires a reduction in the GHG emissions at local level of at least ~13% per year (Figure 11), which is 20x faster than the aforementioned 2010-2019 average of 0.6%/year. That means to reach an annual reduction of -62,300 tonCO₂eq on average between 2020 and 2050 (starting from -242,971 ton CO2eq annual reduction in 2020 to -3,240 ton CO2eq in 2050).

Reviewer 2 Report

The paper has been improved. Here is just small remark: please check the numbering of chapters (e.g., Conclusions).  

Author Response

Thanks. We’ll amend it in the proofs phase, if the paper is finally accepted, given that it seems we are having issues with the template.