Capacity Value from Wind and Solar Sources in Systems with Variable Dispatchable Capacity—An Application in the Brazilian Hydrothermal System

Round 1

Reviewer 1 Report

The paper is interesting from Energies point of view, nevertheless there are several aspects that should be addressed before its publication. Find those comments below:

Major comments

• Paper novelty should be bold in the abstract, introduction and conclusions
• The introduction should be expanded and provide the proper energy context for this research, aspects such as the relevance of the energy storage systems coupled to renewable energy sources is vital for meeting load curve with power sources and to increase dispatch flexibility. There are many research works regarding flexible dispatch of solar energy systems when introducing storage (for example “Flexible electricity dispatch for CSP plant using un-fired closed air Brayton cycle with particles based thermal energy storage system”, Energy 173, 971-984) but there are many other research works for solar CSP and also coupling energy storage systems for wind power plants. Those topics could be discussed in the introduction to provide a wider picture of the paper relevance.
• The authors should clearly indicate the perspectives and prospects of the obtained results in conclusions section
• Provide list of keywords
• The abstract should be focused into paper findings and methodology rather than providing energy general background (that’s for the introduction)

Minor comments

• Provide full reference details
• Reconsider paper title modification in order to include hydropower relevance given in the manuscript
• Avoid using “we / our” in the manuscript
• Consider modifying Figure 1 units
• Figure 19 & 20 should have same axis limits for comparison purposes, clarify why ELCC exceeds 100% in Figure 19

Author Response

Dear, Reviewer.

Thank you for your comments and thorough revision.

We have made changes in the first manuscript version to answer your observations. We have attached our responses to the raised points in the file below. 

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Authors,

Thank You for the opportunity of reading this article.

General statements about the article:

-> article discusses a methodology to calculate the capacity value from RES when the dispatchable generation units have variable capacity. Then the case study for solar and wind sources in Brazil was performed. Thus the article's aim is actual and researches in this area are desirable.

-> The article content suite to Energies journal scope.

-> the organization of the article is correct (contain 5 sections). Section are ordered in correct manner.

-> abstract is adequate to article content

-> Literature review is based on 16. They are related to article content.

-> quality of figures and tables is sufficient.

 

  However, I indicate some issues that require additional clarification:

#1 Keywords

Please propose the keywords to this research.

 

#2 Literature review

Generally, the literature review must be extended. Additionally, there is a lack of actual ones. Thus please add at least 10 related articles not older than 2015 (at least 4 from 2020-2021 range).

 

#3 Methods presentation

For Section 2, Please introduce the proposed research framework more effectively, i.e., some essential brief explanation vis-à-vis the text with a total research flowchart or framework diagram for each proposed algorithm to indicate how these employed models are working to receive the experimental results. It will increase the value of the presentation.

 

 

#4 English

Please also revise the manuscript regarding the personal way of addressing in the text. Please avoid and replace we" or "our" with the impersonal manner of addressing. The text will sound much more professional.

#5 Conclusions

Please extend the conclusions part with future research direction.

 

Technical issue

-> Please revise correspondence information.

Author Response

Dear, Reviewer.

Thank you for your comments and thorough revision.

We have made changes in the first manuscript version to answer your observations. We have attached our responses to the raised points in the file below. 

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors should avoid the use of footnotes.

In Equation 2 FOH, EUDH, SH, OECH and SRH are used and their explanation given as a footnote. It is confusing.

Equation 3, same comment as before.

Line 116. If n stands for the number of generators, why is the Acum. Prob not P_1 on the first line, P_2 on the second line, etc.

Line 117 and 118. There is a discrepancy between the table and the text. The capitalized letter N is used in the table while n is used in the text. Please use the same notation, i.e. change the n for the accumulated probability to another letter.

The authors mix t and t, n and n, N and N. It is very confusing. Please correct that.

In line 202, the authors cite a paper from a Brazilian team in order to show the intra-year and inter-year variations of renewables. Many other sources would be relevant. The authors should justify the choice of this particular reference.

In figure 1, the authors should insert the location in the caption. This figure can be confusing for north hemisphere residents.

Line 240. The authors mention the average wind generation of 2019. Please insert a reference for that value. Is it for the whole Brazil?

Figure 3 to 8. Increase the size of the axis labels and legends.

Line 244. What region of Brazil does SIN refer to?

Line 245. The authors mention that figures 3,4,5 indicate three patterns but the explanation is not substantial enough. The explanation should be extended so that we clearly can see that there are three different patterns.

Line 254-255. How come the load decrease in the winter time?

Figure 6. How can it be that there is no PV generation between January to may 2017?

Figure 14. Same question.

Paragraph line 382-392. Isn’t there a way to “normalize” the ELCC so that it reflects the installed capacity? It seem that it is given a false image when comparing PV to wind, when there is such adiscrepancy in installed capacity between both resources.

Line 369. Shouldn’t it be figures 19 and 20?

Line 370. Shouldn’t it be figure 19?

Line 385. What does FONTES-ONS mean?

Line 395. Shouldn’t it be figure 20?

Line 508. An appendix to the paper is inserted, but its relevance is not justified. Remove the appendix or justify its presence.

Author Response

Dear, Reviewer.

Thank you for your comments and thorough revision.

We have made changes in the first manuscript version to answer your observations. We have attached our responses to the raised points in the file below. 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Dear Authors,

Thank You for the deep revision. All my previous comments were included. Thus I recommend publishing this article.

Good luck in future research.

Best regards,

Reviewer